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ELSA Cable User's Manual

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1. N umber of buffers available Number of buffers in use N umber of buffers available Number of buffers in use Number of bridge packets from the LAN Number of bridge packets from the WAN Number of ARP packets in the query queue Number of ARP packets in the normal queue N umber of IP packets in the normal queue Number of IP packets in the secured queue Number of ICM P packets Number of TCP packets ELSA MicroLink Cable Description of the menu options Queue statistics Statistics on the queue TFTP server queue packets DHCP server queue packets DHCP client queue packets IPr RIP queue packets TFTP queue packets Cable tx M AC queue packets Cable rx M AC queue packets SNM P queue packets TFTP client queue packets DNS tx queue packets DNS rx queue packets IP M asq tx queue packets IP M asq rx queue packets ELSA MicroLink Cable ro N umber of packets in the receive queue of the TFTP server Number of packets in the receive queue of the DHCP server Number of packets in the receive queue of the DHCP clients N umber of packets in the receive queue of the IP RIP module for RIP queries RIP propagations Number of TFTP packets Number of packets to be sent in the M AC chip queue Number packet buffers for reception in the M AC chip queue Number of SNM P packets N umber of p
2. 2 Operating modes and functions 29 Security for VoUrconrigurattofias iaa tanda 29 PassWord protection ssrin teet ap 29 d a 29 Access control via BEP DX e 30 ELSA Cable M Content Security for yur LAN a odes add 30 stum 31 31 The hiding place IP masquerading NAT 31 er 32 ThelProuting table ba bs me e etit noc 32 Dynamic routing with IP RIP ansa ted PI DR 34 Local dae 35 IP masquerading NAT PA 36 Stetit Rl eh den 38 E 39 Automatic address administration With DHCP eenee 40 The DACP Client seeded des atate teas ara 41 The DHCP esa 41 DACP odas e eto dA 42 How the addresses 5510 42 Technical 47 Cable mogaemtechinolgy acd pu oeste 47 Standards 47
3. Server with Headend Cable TV net ELSA icroLink Cable DHCP work as router with DHCP server In this example several computers are connected to the ELSA M icroLink Cable and thus to the Internet using a hub In principle however a single computer can also be connected directly to the ELSA M icroLink Cable 1 Start up ELSA LANconfig by clicking Start gt Programs gt ELSAlan gt ELSA LANconfig ELSA MicroLink Cable Installation and configuration 2 In order for a device to be able to assign addresses to other devices on a TCP IP network it first needs an IP address valid in the LAN itself LAN IP address Click the entry in the device list to open the configuration dialog If an entry doesn t exist yet create a new one using Device gt New Forthe IP address enter 10 0 0 254 or 254 in which x x x stands for the addresses previously in use in your network if applicable Switch to the TCP IP configuration section and on the General tab enter the LAN IP address and the associated netmask f you have not used any IP addresses on your network so far you can assign any address you like from the address space reserved for private use e g 10 0 0 1 with the subnet mask 255 255 255 0 You are thereby also defining the address space that the DHCP server will use for the other devices on the network f you have already configured IP addresses on the computers on the LAN
4. 47 Registration in the cable network eene 48 Network on n ten 50 The network and IIS 50 c 50 52 52 IP routing and hierarchical IP 0 51 0 55 Expansion through local fle WOFKS Ord vertus 57 Appendix A dn DER RU CC 63 Technical data tut 63 Warranty conditions cn qtu DR RUD 65 Declaration of e rh bo deii 67 Description of the menu options sssrin 73 15 Status Operating t Me oie a pce nte RUE 16 SEALS MN 16 bless tatis LCS nde 76 ud 77 Status bridge statistics edema 78 5 5 5 5 5 79 ELSA Cable Modem Content Stat s IP ro ter statistitS abe node tede t nnda 03 config SEGEISEICS T 85 Status QUELIC SEGEISIICS pon eed i aa 85 Status 87 87 Status DHCP client statistics pat slay 88 SOLD 88 89 Set p 89 Seup bridge Oodula accolunt d door tte dandis 90 Setup 5 OCU Ie ci eed
5. 25 Source addresses 91 SOURCE POM 100 Start address err 42 101 Static POURING 32 Statio ous edit c man alto 15 Config Statistics tereti Cote d 08 IP routersS tat SES scatto indi tU S 03 Operating 76 Queue statistics 85 87 79 55 System administrator 101 System location 101 T Table RIP acsi m tentia tege bet 97 jr Geo CENE 99 TCP lt 94 TOP Sciatis 17 32 52 TGPAMPISEQCE Oeo 52 TCP aging minute s sacan obo 94 63 Telnet 93 17 93 oe 76 103 TUS dnte detta usum bai pid 96 Trace code and parameters 21 22 Starting a 21 21 ELSA icroLink Cable 27 Upload System 106 E 101 SiR ih ORE 105 Type of service 96 U RE 99 ae ELSA MicroLi
6. 104 sth 30 31 36 Period of 41 43 Physical medium 50 Point to multipoint connection 51 Point to Point connection 50 POPE BU DBE cra esce erede eroi 38 PPP negotiation 92 Private address spaces 54 Prohibited address ranges 95 PROLOG MN E 52 ARP cn one aate 95 R tota dt hes mid 97 Registered IP address 54 92 Remote 90 but 97 97 nae 50 Otter rt td 33 55 Routing table reor cesare ra cre ch 55 S SOCUMEY eode ete utin 29 30 32 np nt ofc mde 24 Service table oer caben 98 Setup bridge module 90 DHCP module 101 IP router module 94 LAN module aee rediit 89 TCP IP module cus osos tinet Pas 91 WAN module sitet hid 89 Shared M ediUm ssassn 52 57 Single user ACCESS rreren 3l SNMP st osito dedit 24 101 IR d 24 Manager aedem ad 24
7. SS LAN j knows only the LAN with router function address of the LAN In contrast the host is confronted with a more difficult task than the router In case of an interface with a point to point cable the host knows that all packets that it sends through the interface automatically arrive at its router for example In case of the point to multipoint connection to the LAN it has to distinguish two cases how ever A packet with an address outside the LAN is passed on to a router in the LAN that takes care of the further processing of the packet The sending host must send a packet with an address within the LAN directly to the target host since the router in the network does not know the addresses of all the different hosts Data transfer within the LAN Let s use an example to explain this Imagine the hosts of the subnet in the marketing division are linked via a LAN The hosts have IP addresses from the numerical space 137 226 4 1 to 137 226 4 254 the addresses 137 226 4 0 and 137 226 4 255 are reserved the network address is 137 226 4 0 and the netmask is 255 255 255 0 router connected to the LAN provides access to the wide world of the Internet Its LAN interface has the IP address 137 226 4 1 and the M AC address 00 80 C7 6D A4 6E Imagine wanting to send an IP packet from host Smith with IP address 137 226 4 10 and MAC address 00 10 5A 31 20 DF to host M with IP address 137
8. tiae s 57 aeo rrt p gu 89 addresses 58 esci metit carent 58 M anagement Information Base 2 Manager cod nue io epa bran 2 Masquerading 92 98 Masquerading table 99 Media Access 57 50 25 M lt as ec 90 M ultipoint cabling ancien 57 M ultiprotocol capability 58 N 99 NAT cub tumidi 30 31 36 emp 53 NetWork Rund ite dm add 50 Network 50 Network address 53 Network Gables rere tato 50 Network Connection 89 Network Information Center 36 Network 0 52 NIC attesa agde adidas 36 Node ttd Rte 4 0 25 On line media 17 Operating 90 92 94 Operating mioUBS 29 106 50 Password ereere 93 Password protection 29 PaseWord Fequired
9. ier 50 Internet bosco eta rw ino d 31 52 _ p dete 52 Inverse masquerading 98 pav 96 IP acess 17 IP adafess adea i fs RR 17 32 92 ades SES cosi amma te inscio da 53 IP DEORUE t 97 ne tao uci ve DR da 96 IP masquerading 30 31 36 98 simple masquerading 37 supported protocols 38 IP multicast oa ear aaa 97 NetWork ncns 52 IP routing FE annei 31 31 Taller eos od 31 IP routing table 32 95 du nid 92 19 ORE TROP E REOR SUM 52 ISDN HER ORK rdum ot 53 L MT 52 57 3 ases 17 18 23 ELSA MicroLink Cable events 96 Language sou ous sic da aries 104 3 uve ecd edes 3 TAG 3 1 Link Status PED 4 cmi aro 96 Local Area 0 52 local 52 Were SIM CERES 104 lesse turmis erm 23 30 Login DITTO es 29 104 104
10. 91 Setup lP router module roti pied tu 94 Setup SNP OCU scd bdo 101 Setup DHCPssarver module t setenta mid 101 Set p ContiQ n eua dec Erit 103 dC ct 104 ONE PM ede 106 ELSA Cable M Content ELSA Cable O Introducing the ELSA M icroLink Cable E Introducing the ELSA MicroLink Cable Internet access is the main application for the ELSA M icroLink Cable The operator of the cable network to which you have connected your modem may offer additional services or regional information This chapter describes the display elements and connections of the modem accessing the Internet and the characteristics and techniques that ensure fast secure data exchange The precise use of the ELSA M icroLink Cable s features will be explained the following sections and with the aid of the examples in the W orkshop The term router as used in the remainder of the manual refers to the router functions of our ELSA M icroLink Cable The ELSA MicroLink Cable takes the stage This section introduces the unit s hardware It covers the unit s display elements and connection options W hat does the unit look like We would first like to familiarize you with the device You will find a number of LEDs as display elements on the front panel n ELSA MicroLink Cable Introducing the ELSA
11. 7 Installation and Configuration sssini 9 HSCS TED anni E 10 Quick Start Quick configurations sse tima tatis H ure oT 11 Conriguratiofi asia cdit pot lan 11 COMMOUPALION AS tnfra fo eta deer toas 13 Set up the workstation computers Windows 95 or 98 15 Configuration mod s tn n Erasaer ar E Nub E E 17 The user friendly method 17 Requirements for inband 17 Alternatively addresses can be managed by the DHCP server 17 Starting inband configuration using ELSA LANconfig 18 Start up inband configuration using telnet eene 18 Configuration COMMAaNdS voto 19 What s happening on the susciter rn te cre ru ua Cam 21 Trace OULDULS aet Da eain acd adel rie rct 21 New firmware With FirMmSafe lt patefecit mp ae to itin 22 This is how FirmSafe ir rtt eT repu t ertet e utet 22 How to load New SoftWare coenae at edere rene 23 Configuration using SNMP aos oi cadi d etit Pado dd tbe oh 24 24 Accessing tables and parameters using 5 25 The M anagement Information Base M 1
12. 1 This menu allows you to display the statistics from the remote configuration area It allows you to retrieve information on the number of past and present configuration sessions at any time The informaton is broken down into the categories LAN WAN and outband port Config statistics Remote configuration statistics LAN active connections LAN total connections Cable active connections Cable total connections Login errors Login locks Login rejects Delete values Status Queue statistics Current number of active configuration connections from the LAN Total number of configuration connections from the LAN up until the present Current number of active configuration connections from the cable network Previous number of active configuration connections from the cable network Total number of defective logins Number of login locks Number of login attempts while the login lock was active Deletes the config statistics These statistics allow you to observe the flow of the individual packets through the various modules of the devices Queue statistics Statistics on the queue LAN heap packets LAN queue packets Cable heap packets Cable queue packets Bridge internal queue packets Bridge external queue packets ARP query queue packets ARP queue packets IP queue packets IP urgent queue packets ICM P queue packets TCP queue packets
13. This colossal performance is shared by up to 2000 users connected to the same cable section however This is referred to as the use of a shared media The data flow in the cable network does not take place at a constantly high volume but in irregular intervals Also it s unlikely that all 2000 participants will be using the network simultaneously so the available bandwidth is certainly adequate to ensure the fast transfer of data The cable network operators have the option of limiting the available bandwidth for individual participants or offering several channels with 43 M bps each Please contact your network operator for further information on transfer rates and pricing models ELSA MicroLink Cable Backbone direct connection to the Internet Introducing the ELSA M icroLink Cable 5 Backbone The simple transfer rate betw een the network operator and participant does not by itself determine the speed at which the Internet can be accessed The network operator must also forward data destined for the Internet to a backbone The dimensioning of this connection ultimately determines the speed at which you can surf The backbone can become a bottleneck if a large number of participants want to access Internet data simultaneously and the network operator does not have an adequately dimensioned connection to the Internet Internet at all times always online One of the biggest advantages of cable modem technology is the continuous
14. 6E The router extracts the IP packet from the LAN packet and finds out about the IP address of host External In the routing table the router then looks for the network address of this host and thus finds the interface through which to pass on the IP packet LAN coupling on MAC basis You know how LANs simplify the connection of computers to a local network Nearly all house networks are thus LAN based In some cases a LAN is covers such a large area that the physical characteristics of the cable prohibit the connection of any more computers This results in the necessity to couple up several LANs in such a way that electrically and in terms of the M AC protocol they act as independent LANs but for the IP protocol look like one big LAN This coupling of LANs is carried out using bridges A bridge works somewhat like a router but uses only M AC addresses for routing not IP addresses Since M AC addresses do not give any information on the structure of the network the way IP addresses do every bridge has to know all M AC addresses in the entire LAN And so we encounter the same problem that we had with the routers before the introduction of subnets As the LAN expands it will at some point exceed the capacity of the address tables of the bridges So one cannot use bridges to connect an infinite number of LANs On the other hand the unstructured M AC addresses allow the bridges to learn automatically about the location of computers in the net
15. Broadcast multicast destination M AC address source M AC address automatic filtering of local and remote stations TCP UDP port filtering source and destination net Work filter Internet access using a single IP address via IP address and port implementation static dynamic IP address assignment via DHCP masking of TCP UDP ICM P and FIP DNS forward ing inverse masquerading for intranet IP services Cable network operator User Via SNM P and TFTP transfer of configuration files and firmware updates Via the cable TV network or LAN with TCP IP pass word protection ELSA LANconfig SNM P telnet LEDs for LAN and cable TV network status factory default button reset button 12 V AC with AC adapter for 230 V US version 110V 10 VA Temperature 5 40 C humidity 0 8096 non condensing Rugged metal case LEDs on front panel connections on rear panel Dimensions 158 x 32 x 135 mm W x H x D ELSA icroLink Cable TE Appendix Technical data ELSA MicroLink Cable Package contents Accessories AC adapter F to IEC169 2 adapter connector cable for cable TV network 10Base T cable Software Configurations software ELSA LANconfig TFTP client Documentation Comprehensive manual and ELSA CD ROM Installation Guide German English French Italian Dutch Spanish Service Warranty 6 years ELSAcare In the event of a warranty claim within the first 100 days following the purchase replacement product will
16. VALUE or TABLE cd M ENU or lt TABLE gt set VALUE set VALUE del VALUE do ACTION parameters passwd repeat sec ACTION time language language exit quit x Calls up help text Displays the contents of M ENU VALUE or TABLE Switches to the M ENU or TABLE specified This resets the VALUE Insert a space between all entries in table rows An leaves the entry unchanged Shows you which values can be specified here Deletes a table row Executes the ACTION according to any parameters specified Allows a new password to be specified The old password if there is one must be entered first The new password must then be entered twice and con firmed each time with Repeats the ACTION at an inter val of the number of seconds specified Any key can be used to terminate the repetition Sets the system time and date Sets the language for the cur rent configuration session Configuration is terminated dir status wan statistics displays the current WAN statistics cd setup tcp ip module or cd se tc short switches to the TCP IP mod ule set IP address 192 110 120 140 sets a new IP address set setup name AACHEN assigns the name AACHEN to the device del se wan AACHEN Deletes the entry for the remote sta tion AACHEN do firmw are firmw are upload starts the upload of new firmware repeat 3 dir status wan statistic
17. allocate a free address to the device from the address space you used previously 3 tab enable the Router option cablemodem Configuration Configure R General DHCP Routing Fiter Masquerading P outer active Local routing active IP routing normal m ICMP routing normal z Onthe M asquerading tab enable the M asquerading function This will conceal the IP addresses in use in your local network from the Internet This protects your network from intruders and avoids conflicts with other networks that may be using the same addresses internally also see IP addressing and IP masquerading 5 Go tothe tab and set the DHCP server to Auto mode This lets the unit handle the local IP address administration by itself The ELSA M icroLink Cable determines the valid address pool by itself unless you specify otherwise cablemodem Configuration HES Configure General DHCP Routing Filter Masquerading DHCP server Maximum lease time fE 000 minutes Default lease time 500 minutes ELSA MicroLink Cable FIO Installation and configuration 6 Go then to the Bridge section and deactivate the option Bridge the General tab 2 Save the configuration with OK The ELSA M icroLink Cable is now ready for use in router mode Open your W eb browser and off you go into the W
18. be provided Support Via hotline and Internet ELSA MicroLink Cable Warranty conditions The ELSA AG warranty valid as of 01 1998 is given to purchasers of ELSA products in addition to the warranty conditions provided by law and in accordance with the following conditions 1 2 Warranty coverage The warranty covers the equipment delivered and all its parts Parts will at our sole discretion be replaced or repaired free of charge if despite proven proper handling and adherence to the operating instructions these parts became defective due to fabrication and or material defects Also we reserve the right to replace the defective product by a successor product or repay the original purchase price to the buyer in exchange for the defective product Operating manuals and any supplied software are excluded from the warranty M aterial and service charges shall be covered by us but not shipping and handling costs involved in transport from the buyer to the service station and or to us Replaced parts become property of ELSA ELSA are authorized to carry out technical changes e g firmware updates beyond repair and replacement of defective parts in order to bring the equipment up to the current technical state This does not result in any additional charges for the customer A legal claim to this service does not exist Warranty period The warranty period for ELSA products is six years E
19. das Erzeugnis den folgenden Schutzanforderungen entspricht This is to confirm that this product meets all essential protection requirements relating to the Niederspannungs Richtlinie 73 23 EW Low Voltage Directive 73 23 EEC EMV Richtlinie 89 336 EW G EMC Directive 89 336 EEC Zur Beurteilung der Konformitat wurden folgende Normen herangezogen The assessment of this product has been based on the following standards EN 50082 1 1992 Teile parts EN 61000 4 2 3 4 6 11 EN 50081 1 1992 Teile parts 550228 A 1 1995 A2 1997 EN 60950 1992 A1 1993 A2 1993 A3 1995 4 1997 11 1997 Diese Erkl rung wird verantwortlich f r den Hersteller Importeur On behalf of the manufacturer importer ELSA AG Sonnenweg 11 D 52070 Aachen abgegeben durch this declaration is submitted by Aachen 19 uli 1999 l Aachen J 19 1999 i V Peter Wieninger Bereichsleiter Entwicklung VP Engineering ELSA icroLink Cable ELSA MicroLink Cable Index A ACCESS pauio NN RR 30 ACCESS 010 0 5_ 57 ACCESS 90 Access 93 Address Administration 17 Address administration 40 42 102 Address ranges 95 OIE Well k 52 ARPICSCDB erased ament ma ur tarii Fra 93
20. or in cases of intentional act or culpable negligence Claims for compensation of lost profits indirect or consequential detriments are excluded ELSA is not liable for lost data or retrieval of lost data in cases of slight and ordinary negligence In the case that the intentional or culpable negligence of ELSA employees has caused a loss of data ELSA will be liable forthose costs typical to the recovery of data where periodic security data back ups have been made The warranty is valid only for the first purchaser and is not transferable The court of jurisdiction is located in Aachen Germany in the case that the purchaser is a merchant If the purchaser does not have a court of jurisdiction in the Federal Republic of Germany or if he moves his domicile out of Germany after conclusion of the contract ELSA s court of jurisdiction applies This is also applicable if the purchaser s domicile is not known at the time of institution of proceedings The law of the Federal Republic of Germany is applicable The UN commercial law does not apply to dealings between ELSA and the purchaser ELSA MicroLink Cable Declaration of conformity KONFORM ITATSERKLARUNG DECLARATION OF CONFORM ITY Diese Erkl rung gilt f r folgendes Erzeugnis This declaration is valid for the following product Gerateart Modem Type of Device Typenbezeichnung MicroLink Cable Product Name Hiermit wird best tigt
21. which also means all computers S st S end Source port range that is to be filtered A range of 0 to 0 means that no source port is affected by this filter Dst address Dst netmask A subnetwork of the local network for which the filter is valid can be entered here A destination address of 0 0 0 0 means that the filter is applied to all computers A network mask of 0 0 0 0 means that the filter is applied to all networks which also means all computers D st D end Destination port range that is to be filtered A range of 0 to 0 means that no destination port is affected by this filter Action The filter can discard not forward or accept forward packets Interface Select whether the filter should apply to the LAN interface the interface to the cable TV network or both Direction Select whether the filter should apply to incoming outgoing or all packets Broadcast Select whether all broadcast packets including unicast or only multi broadcast packets should be filtered Number matches Number of packets that fit the filter The table entries are sorted in a similar fashion to the IP router table The longest network mask is placed on top For two network masks of equal length the one with the smallest IP address is placed on top ELSA MicroLink Cable Send Traps IP Trap Table Administrator Location Operating Description of the menu options 9 Network masks and IP addresses of 0 0 0 0 can be used as wildcar
22. which knows the route to the destination network this response is known as an ICM P redirect The workstation computer then accepts this address and sends the data packet straight to the other router Certain computers how ever do not know how to handle ICM P redirects To ensure that the data packets reach their destination anyway use local routing in ELSA LANconfig in the TCP IP configuration section on the Router tab the Setup IP Router ELSA icroLink Cable Operating modes and functions Module Local Routing menu This tells the router in your device to send the data packet to the other responsible router The router will then no longer send any ICM P redirects This may seem to be a good idea in principle but local routing should still only be used as a last resort since this function leads to doubling of the number of data packets being sent to the destination network required The data is first sent to the default router and is then sent on from there to the router in the local net which is actually responsible IP masquerading NAT PAT One continually grow ing problem for the Internet is the limited number of generally valid IP addresses available In addition to this the allocation of fixed IP addresses for the Internet by the Network Information Center NIC is an expensive process What is more obvious than having several computers share one IP address This particular solution is called IP ma
23. ARP Gr Chat RR 93 ARP aging minute s eene 94 m de cds re toten t ut 102 B 30 106 Bridge filtering data packets 40 ua tee 39 abad 90 Bridge 90 0 astute teen in b us 90 Broadcast address 54 Broadcast data packets 90 Broadcast 5 57 Brute ice 29 50 Cable NetWork socer etu dunt mem 53 91219 93 CE M 1 Celle DN 50 COMMUNITIES 25 5 104 Configuration Commands hb nmn 19 SNMP 24 Configuration options 103 Index Ej D Data 50 Default oed den iae 95 Destination addresses 91 Destination network eene 95 Destination t 100 DHCP 40 101 nico MY Arden 41 DHCP SIT atas enda eid 17 41 101 Display elements 1 Distance of a route 3
24. Description of the menu options Overview of the menus Setup Status Name 9 Operating time Cable module 9 Current time LAN module 7 Cable statistics Bridge module LAN statistics TCP IP module Bridge statistics IP router module TCP IP statistics SNM P module IP router statistics DHCP server module Config statistics Config module Queue statistics SYSLOG module M CNS statistics Firmware Init status Version table DHCP client status Table firmsafe Output internal status messages c Mode firmsafe Delete values Timeout firmsafe Other Em Test firmware Em Boot system Em Firmware upload Factory default system g Upload system ELSA MicroLink Cable Status Description of the menu options The Status menu contains information on the current status and the internal sequences of operations in the LAN and in the cable network which can relate to the data transmission route e g registration with the headend or to statistics e g number of data blocks received and transmitted The statistics displays are an important aid for verifying correct operation and optimizing parameter settings In addition they provide valuable information for error analysis when malfunctions occur M ost status displays are continually updated and can be deleted with a value or set to 0 in
25. availability of the Internet While normal Internet connections need to be established as required all cable modem users on a cable section can be permanently registered with the headend The multiport capabilities of the remote stations ensure that other participants are not blocked due to a lack of connections The advantages of this permanent Internet connection Immediate availability of all information Your e mail comes to you directly not just when you pick it up To view a Web page just open your browser and don t worry about connecting to your provider Your own Internet server Until now running your own Internet server generally meant having an extremely expensive leased line to the provider Now you have one If you would like to set up your own W eb server for your company you can now do so and have it accessible at all times via the cable modem at no additional cost More than just Internet Together with the appropriate remote stations cable modems form the connection between network participants private or business and the network operator Very high throughputs and thus very fast data transfers can be realized using such a connection In addition to providing fast Internet access this creates a number of other interesting options for the evolution of network operators into information service providers Regional content Cable network operators generally have a local or regional orientation due to the stru
26. be received by one specific recipient unambiguous connection ELSA MicroLink Cable Point to multipoint connection Technical basics Host Host 5 Data packet 4 a EE c 7 kE M edium 7 Access to the Internet is also established through point to point connections Even though the data packets are sent from the host at the Internet user to the host at the Internet provider Server via several routers every data packet still has its own specific destination Furthermore the routers will only forward the data packets to one recipient That s why we also call this connection unambiguous Connections to other Host routers Host z JC y Internet user Web server Strictly speaking the term point to point connection is not quite correct For our purposes though it is sufficient to distinguish this kind of connection from the following point to multipoint connections Generally speaking it would be uneconomical to directly connect all computers in a network via point to point connection cables as the computers would then require multiple interfaces Computers in a network are therefore plugged into a joint medium shared by all hosts The sender simply sends its packet with instructions concerning the recipient to the medium to which other hosts are connected The data packet arrives at every host in the network Each host
27. computers IP address Network mask Broadcast address DNS NBNS Default gatew ay Period of validity for the parameters assigned The DHCP server takes the IP addresses either from a freely defined address pool or determines the addresses automatically from its own LAN IP address ELSA icroLink Cable Operating modes and functions DHCP off or The DHCP server in the devices of ELSA can be set to three different states The DHCP server is permanently active The configuration of the server validity of the address pool is checked when this value is entered When correctly configured the device will be available to the network as a DHCP server n the event of an incorrect configuration e g invalid pool limits the DHCP server is disabled and switches to the off state off The DHCP server is permanently disabled auto The server is in automode In this mode after switching it on the device looks for other DHCP server within the local network The device then disables its own DHCP server if any other DHCP servers are found This prevents the unconfigured router from assigning addresses not in the local network when switched on The device then enables its own DHCP server if on other DHCP servers are found Whether the server is active or not can be seen in the DHCP statistics The default state is auto How are the addresses assigned IP address assignment Be
28. describe the path of the data packet This procedure is also called static routing since you make these entries yourself and they remain unchanged until you either change or delete them yourself Naturally there is also dynamic routing too The routers use the routes in this way to exchange data between themselves and continually update it automatically The static routing table can hold up to 64 entries the dynamic table can hold 128 The IP router looks at both tables when the IP RIP is activated The routing table can be found in the configuration tool ELSA LAN config in the TCP IP configuration section on the Router tab or in the Setup IP router IP routing menu This then is how an IP routing table might look IP address IP netmask Router Dis tance 192 168 0 0 255 255 0 0 0 0 0 0 0 172 16 0 0 255 255 0 0 0 0 0 0 0 10 0 0 0 255 0 0 0 0 0 0 0 0 ELSA MicroLink Cable Operating modes and functions IP address IP netmask Router Dis tance 224 0 0 0 224 0 0 0 0 0 0 0 0 255 255 255 255 0 0 0 0 CABLE 1 192 168 130 0 255 255 255 0 191 168 140 123 1 W hat do the various entries on the list mean IP addresses and IP network masks This is the address of the destination network to which data packets may be sent and its associated network mask The router uses the network mask and the destination IP address of the incoming data packets to check whether the packet belongs to the destination network in question The
29. device operates as a DHCP server ELSA MicroLink Cable L Description of the menu options A Start address pool End address pool Netmask Broadcast M ax lease time minute s Off The device does not operate as a DHCP server Auto The device regularly checks whether there is another DHCP server in the LAN If not it operates as a DHCP server and issues IP addresses to local clients If there is no cable or LAN IP address entered in the TCP IP module e g factory setting the cable modem will issue IP addresses from the address range 10 0 0 2 10 0 0 253 to all DHCP clients in auto mode The IP address assigned is taken from the address pool selected Start address pool to End address pool Any valid addresses in the local network can be entered here If 0 0 0 0 is entered instead the device will determine the appropriate addresses start or end from the settings under Setup TCP module The procedure is as follows If only the cable or LAN IP address is entered the start or end of the pool is determined by means of the associated network mask If both addresses have been specified the LAN IP address has priority for determining the pool The start address of the pool is either the address given in the DHCP module or the first valid address in the local network The end address of the pool is either the address given in the DHCP module or the last valid address in the local network A valid address
30. down according to the various TCP IP sub protocols The TCP IP statistics contain the following parameters TCP IP stati Statistics from the TCP IP area stics ARP statistics 3 Statistics from the ARP area IP statistics Statistics from the IP area ICM P statistics Statistics for ICM P packets TFTP statistics Statistics for TFTP operations TCP statistics Statistics for TCP packets from TCP sessions to the router DCHP statistics Statistics from the DCHP server Delete values g Deletes TCP IP statistics The substatistics then provide you with further parameters for the individual menus Status TCP IP statistics ARP statistics These statistics include the following values ARP LAN rx Number of ARP requests and responses received from the LAN ARP LAN tx Number of ARP requests and responses sent to the LAN ARP LAN errors Number of ARP requests incorretly received from the LAN ARP cable rx Number of ARP requests and responses received from the cable network ARP cable tx Number of ARP requests and responses sent to the cable network ARP cable error Number of ARP requests incorrectly received from the cable network Table ARP Displays ARP table Delete values Deletes ARP statistics Table ARP There are 128 entries with ARP information in the ARP table It has the following layout IP address Node ID Last access Connect IP address that has previously been Associated MAC Time si
31. eb with a whole new sensation of speed If necessary filters can be defined to restrict the exchange of data packets between the local network and the Internet This lets you define restrictions on the workstations that can access the Internet or on specific pages of the Internet that cannot be view ed Setup the workstation computers Window s 95 or 98 We will now briefly show you how the workstation computers must be set up e g under Windows 95 and Windows 98 to ensure problem free communication between the computers on the TCP IP network and the router if this has not already been done TCP IP installation Install TCP IP by clicking Start gt Settings gt Control Panel gt Network gt Add Protocol Select icrosoft under M anufacturers and TCP IP under Network Protocols Obtain IP addresses automatically use DHCP Here s how to set individual workstations to automatically obtain an IP address Start gt Settings gt Control Panel gt Network gt TCP IP gt Properties gt IP Address gt Obtain an IP address automatically Delete any existing entries for DNS servers and gateways on the Gateway and DNS Configuration tabs and disable the DNS option When rebooting the workstation will look for a DHCP server in the network and will allow the server to assign it an IP address and a netmask Configuring fixed IP addresses not using DHCP If you do not wish to use a DHCP server on your network you should con
32. lt lt _ k m amp 5 l d SS z7 PERLES s As an example think of a company with one large network in which the different divisions are incorporated as small subnets The address of the network for the marketing division is made up hierarchically from the address of the company and that of the department Whenever a host external to the company network sends a packet to a host in the Example Inc this is what happens The sender gives the packet the destination address host Smith M arketing Example Inc All an external router that establishes the connections to other networks has to know is how to reach Example Inc As soon as it receives a packet with the address for Example Inc it passes the packet on to the router responsible for Example Inc The router at Example Inc receives the packet and extracts from the address the information that it is directed at Example Inc Since it is itself part of Example Inc it takes a closer look at the address to find the name of the division It then passes the packet on to the router in the marketing division The router in the marketing division receives the packet and extracts from the address the information that it is directed at the marketing division of Example Inc Since it is itself part of this division it takes a closer look at the address to find the name of the host It then passes the packet
33. network You can imagine that as they grow these tables may exceed the capacity of the router the Internet as a worldwide linking up of publicly accessible IP computers contains several millions of hosts For this reason hierarchical IP addresses were introduced This means dividing the IP network into subnets in which IP addresses are appointed from a coherent numerical range It is possible to establish several hierarchy levels so that different subnets can be merged The principle is similar to the hierarchical address used by paper mail consisting of a country a city a street and a number The consequences of this hierarchical IP addressing Since all hosts within one network have the same network address the host address is sufficient for the hosts within this network to communicate with one another A router has to know both the addresses of the hosts that are directly connected to it and the addresses of all networks and subnets that are reachable via adjacent routers It 15 not necessary for a router to know all other possible IP addresses ELSA icroLink Cable Technical basics Host Smith Ha gu External host A Marketing 60 Example Ll HJ co mg LSS a Inc s router C mE gt Superordinate network ul e m Example Inc o gu External router as a Development connection to other net
34. network i e IP networks can use the physical connections of the LAN to establish connections between the hosts and the routers LAN refers to a limitation of the area covered by the network not a restriction of the number of workstations connected to it ELSA icroLink Cable E Technical basics M AC address IP in the LAN Specific LAN addresses hardwired into the interfaces by their manufacturers are used to manage the transfer in the LAN Since the LAN addresses are used for communication via the M AC protocol they are called MAC addresses They can be thought of as the fingerprint of the interface hardware M AC addresses can look like this for example 00 80 7 60 4 6 M AC addresses are independent of IP addresses IP host whose interface works through a LAN has an IP and a M AC address W hereas the structure of IP addresses with its similarity to postal addresses is supposed to simplify routing in enormous IP networks the fingerprint like M AC addresses are designed to make the connection to a LAN as easy as possible Transfer in LAN is also packet oriented Every M AC packet contains the M AC addresses of the source and of the recipient Although every packet is received by all computers it is processed only by the target computer There is an additional M AC broadcast address that is processed by all computers in the LAN Every LAN packet contains an entry with the type of the network protocol An IP packet can
35. or edit the data on your computers A ELSA M icroLink Cable offers you various ways of restricting access from outside Data encryption Data packet filtering IP masquerading also known as NAT or PAT ELSA MicroLink Cable Operating modes and functions Encryption Since cable modems transfer data via a cable shared by many participants data should be encrypted to prevent access by the other participants All data between the modem of the provider and the modem of the end users is automatically transferred in an encrypted state This is where the DES encryption Data Encryption Standard with a code length of 56 comes in In addition the code in use is repeatedly changed during the transfer of data This guarantees the highest level of protection TCP IP packet filters You can use your entries in the routing table to determine quite precisely which data should be transferred Additionally you can use a special entry in the Router name field to reject whole groups of IP addresses Occasionally you may wish to restrict a transmission even further You can do this using a characteristic of TCP IP which is to send port numbers for destination and source as Well as the source and destination IP addresses with a data packet The destination port in a data packet stands for the service to be addressed in the TCP IP network The destination ports are fixed for the various services on the TCP IP network The source ports on the other han
36. packet that it sends directly to host 5mith the M AC address 00 10 5A 31 20 DF of host Smith is extracted from the sender field in the ARP request packet Host 5mith recognizes this as an answer to its request extracts the M AC address 00 10 5A 31 20 EB from the ARP response packet and enters it into its ARP table Host 5mith a a M iller E ARP response 137 226 4 20 00 10 5 31 20 Then it can finally turn to its original task sending the IP packet to host M It now finds the entry IP address 137 226 4 20 corresponding to M AC address 00 10 5A 31 20 ELSA MicroLink Cable Technical basics in the ARP table and tells its LAN interface Send this IP packet to the computer with the M AC address 00 10 5 31 20 Data transfer from the LAN onto the Internet Imagine the second task sending an IP packet from host Smith to the remote host External with IP address 151 189 12 43 Host Smith compares the IP address with its network address and realizes that host External is located outside the LAN So host External can only be reached through the router Host Smith finds out the MAC address of the router 00 80 C7 6D A4 6E by looking up the router s IP address in the ARP table if necessary another ARP request is made So host Smith tells its LAN interface Send this IP packet to the computer with the LAN address 00 80 C7 6D A4
37. sends a packet to the Internet simple masquerading If on the other hand a computer sends a packet from the Internet to for example an FTP server on the LAN from the point of view of this computer the router appears to be the ELSA icroLink Cable ELM Operating modes and functions FTP server The router knows the IP address of the FTP server in the LAN from the entry in the service table in ELSA LANconfig in the TCP IP configuration section on the tab or in Setup IP Router Module Masquerading Service Table menu The packet is forwarded to this computer All packets that come from the FTP server in the local network answers from the server are hidden behind the IP address of the router The only small difference is that Access to a service port in the user s LAN from outside must be defined in advance by specifying a port number The destination port is specified with the LAN IP address of for example the FTP server on a service table to achieve this When accessing the Internet from the LAN on the other hand the router itself makes the entry in the port and IP address information table The table concerned can hold up to 2048 entries that is it allows 2048 simultaneous transmissions between the masked and the unmasked netw ork After a specified period of time the router however assumes that the entry is no longer required and deletes it automatically from the table Which protocols can be tra
38. table is automatically created and managed by means of a hash procedure It comprises max 512 entries Entries in the bridge table may appear as shown below when the bridge has acquired local and remote M AC addresses over time Node ID Last access Forw Filter Flag 00a05702000a 4 tics local 0800096483D 4 105073354 tics local 00001b157de0 105079059 tics remote The last access time to occur since the system was switched on is stored as a multiple of 9 ms tics The forward flag reflects the location of the M AC address An entry in the form 00 057 is the unique M AC address of the device The forward flag column is output for remote configuration only This column is not included in the display This option allows you to specify whether broadcast data packets are to be transmitted always pos default never neg or only when a connection exists sem This option allows you to specify whether multicast data packets are to be transmitted always pos default never neg or only when a connection exists sem ELSA MicroLink Cable O Filter type Filter table Description of the menu options The pos setting for broadcast or multicast may lead to higher charges depending on the pricing model of the cable network operator during due to the higher data volume transferred Setup Bridge module LAN configuration Dest addresses This menu item enables all settings required to filter des
39. the Configure 72 button or the Edit gt Edit Configuration File option reads the device s current settings and displays the general device information The remainder of the program s operation is essentially self explanatory or covered in the online help You can click on the question mark top right in any window or right click on an unclear term at any time to call up context sensitive help Start up inband configuration using telnet Start inband configuration using telnet with the command from a DOS box telnet 10 1 80 125 Telnet will then establish a connection with the device using the IP address After the entry of the password if you specified one to protect the settings all commands from the Configuration Commands section are available ELSA MicroLink Cable Configuration commands Configuration modes EJ Enter commands and path specifications using the normal DOS or UNIX conventions if you are using telnet or a terminal program to configure the device Enter a forward slash or backslash to separate the path specifications You do not need to write out commands and table entries in full an unambiguous abbreviation will do The entries for the categories M ENU VALUE TABLE TABINFO ACTION and INFO will be displayed while configurations are made and may be modified You can use the following commands to do this This command means this for instance or help dir list Il Is M ENU
40. thus sends everything that it cannot forward or transfer over other routes to the cable network operator s headend To route all data packets to a specific network e g via an ISDN router in your LAN to another enter the IP address of the other network and the netmask in the table and enter the local IP address of the router under Router The following assumes that your local network is using the IP addresses in the address range 10 1 0 0 netmask 255 255 255 0 The ISDN router has the local IP address 10 1 0 99 the other local network that of your branch office uses 10 2 0 0 netmask 255 255 255 0 With the following entries the cable modem will forward all data packets for the other network to the ISDN router and ELSA MicroLink Cable Description of the menu options A Loc routing Routing method ICM P routing method sends all other data packets into the cable network insofar as these are not in forbidden areas IP address IP netmask Router name Distance 192 168 0 0 255 255 0 0 0 0 0 0 0 172 16 0 0 255 240 0 0 0 0 0 0 0 10 2 0 0 255 255 255 0 10 1 0 99 0 10 0 0 0 255 0 0 0 0 0 0 0 0 255 255 255 255 0 0 0 0 Cable 0 Enable local routing for this function Local routing enables the router to forward data packets via the local network The local routing is necessary if the router as the default gateway for the workstations receives packets for destination networks to which it cannot establish a connect
41. transferred insofar as that computer has already sent data to the Internet It s thus not necessary to worry about the assignment of IP addresses The computers in your local network receive their IP addresses directly from the DHCP server of the cable network operator ELSA MicroLink Cable Installation and configuration Computer workstation in LAN IP address assignment 1 UE SSS Z 4 a m Server with Headend Cable TV net ELSA M icroLink Cable DHCP Work as bridge In this example only one computer is connected to the Internet via the ELSA M icroLink Cable In principle however several computers can be connected to the ELSA M icroLink Cable using a hub for example if the network operator permits O 1 Start up ELSA LANconfig by clicking Start gt Programs gt ELSAlan gt ELSA LANconfig 2 Click the entry for the ELSA MicroLink Cable in the device list to open the configuration dialog If an entry doesn t exist yet create a new one using Device New Forthe IP address enter 10 0 0 254 or x x x 254 in which x x x stands for the addresses previously in use in your network if applicable Go to the Bridge section and activate the option Bridge on the General tab cablemodem Configuration 2 x Configure Bridge v Bridge active Bridge aging 30 minutes 3 Go to the TCP IP configuration section and on the Router tab disable the Router option Also deactivate the
42. tx bytes LAN rx broadcasts LAN rx multicasts LAN rx unicasts WAN rx broadcasts Number of data packets received Number of data packets sent Number of data packets incorrectly received Number of data packets incorrectly sent N umber of packets without a suitable receive module bridge router Number of data packets discarded by the NIC Number of buffers available Number of buffers in use Number of packets discarded due to a lack of buffers Number of collisions during a send procedure Number of bytes received from the LAN Number of bytes sent to the LAN Number of broadcast packets received from the LAN Number of multicast packets received from the LAN Number of directly addressed packets received from the LAN Number of broadcasts received from the WAN ELSA MicroLink Cable Description of the menu options Table bridge LAN statistics Running status displays WAN rx multicasts 9 Number of multicasts received from the WAN WAN rx unicasts 9 Number of unicasts received from the WAN Delete values E Deletes LAN statistics Status B ridge statistics This option allows you to display statistical information relating to the bridge The bridge statistics contain the following parameters Bridge statistics Running status displays Brg LAN rx Brg LAN tx Brg LAN filters Brg LAN broadcasts Number of data packets received fro
43. users share a single cable Bandw idth Throughput transfer capacity Node or hub Please check the position of the Node Hub switch when connecting the unit to the LAN As the factory default the switch is set to Node In this setting the device acts as a node on a network It can in this case only be connected to a hub not directly to the network card of a computer Set the switch to Hub if you do not wish to connect the device to a hub but directly to a workstation In this setting the lines for sending and receiving the data are crossed Look at the link status LED Link to check if the node hub switch is set correctly The highlights of the ELSA MicroLink Cable The cable modem is a new Internet access technology that is now competing with conventional modems Internet modems and small ISDN routers To take maximum advantage of your ELSA M icroLink Cable you should know the areas and characteristics in which cable modems have the technological edge Fast Internet Cable modems use a split transfer rate depending on the direction of the signals Downstream refers to the transfer of data from the network operator to the participant upstream is the opposite direction This asymmetrical split is quite acceptable since users generally receive far more information from the Internet than they send to it Cable netw ork Up to 43 M bps can be transferred downstream upstream transfer speeds reach up to 10 M bps
44. what happens 192 168 0 0 255 255 0 0 0 0 0 0 0 Excludes transmission of all data 172 16 0 0 25525500 0000 10 0 0 0 255 0 0 0 0 0 0 0 0 224 0 0 0 224 0 0 0 0 0 0 0 0 255 255 255 255 0 0 0 0 CABLE 1 All data packets which cannot be allocated to the entries listed above are transmitted into the cable network Dynamic routing with IP RIP In addition to the static routing table ELSA routers also have a dynamic routing table containing up to 128 entries Unlike the static table you do not fill this out yourself but leave itto be dealt with by the router itself It uses the Routing Information Protocol RIP for this purpose This protocol is used by all devices with RIP to exchange information regarding the reachable routes W hat information is propagated by IP RIP A router uses the IP RIP information to inform the other routers in the network of the routes it finds in its own static table The following entries are ignored in this process Rejected routes with the 0 0 0 0 router setting Routes referring to on other routers in the local network Which information does the router take from received IP RIP packets W hen the router receives such IP RIP packets it incorporates them in its dynamic routing table which looks something like this IP address IP netmask Time Distance Router 192 168 120 0 255 255 255 0 1 2 192 168 110 1 192 168 130 0 255 255 255 0 5 3 192 168 110 2 192 168 140 0 255 255 255 0 1 5 192 1
45. 00000 10101000 01111000 11111101 Netmask 255 255 0 0 11111111 11111111 00000000 00000000 Network address 192 168 0 0 11000000 10101000 00000000 00000000 You can see from this that an IP address alone is not enough A host can only be identified unambiguously in combination with a netmask ELSA MicroLink Cable Technical basics And you can also see that there are more bits available to identify the individual hosts in a connected network if there are fewer bits in a netmask that contain a one While only 254 different addresses could be allocated in the first example with the netmask 255 255 255 0 the second example has as many as 254x254 64516 different addresses available The first and the last digit of an address space are reserved for the network address and the broadcast address addresses for packets to all hosts in an IP network In the netmask 255 255 255 0 this is the 0 forthe network address and the 255 for the broadcast address A new notation of the netmask simply attaches the number of bits available for the network address to the IP address 137 226 4 101 24 The number after the slash tells us that the first 24 bits indicate the network address This notation reduces the length of the entries in the routing tables IP address The IP addresses must be unique within a specific network in order to avoid confusion management Since the Internet is based on TCP IP and thus uses IP addresses for its millions of connecte
46. 226 4 20 and M AC address 00 10 5A 31 20 EB Using the network address and the netmask host 5mith recognizes that host is located in the own network It therefore has to send the packet through the LAN directly to host Miller Unfortunately the LAN interface cannot say Send the IP packet to IP address 137 226 4 20 because the LAN interface only understands M AC addresses This is why every host has to manage a table that translates IP addresses to MAC addresses But how do the entries end up in the table They could be entered manually but that would not satisfy the objective of making the connection of a new computer to the LAN as easy as possible Therefore the LAN has a special mechanism that automates this process the Address Resolution Protocol ARP The table itself is called the ARP table Whenever a host does ELSA MicroLink Cable Technical basics not find an entry in the table for a particular IP address in our example 137 226 4 20 it sends an ARP request packet to all hosts in the LAN with the LAN broadcast address as a target address Host Smith ARP requestto _137 226420 lt a plur ID EY Be 3 m Pap Ms ost miter d This ARP request packet is simply a question to all hosts listening to the IP address 137 226 4 20 Host M iller receives the packet feels addressed and answers with an ARP response
47. 3 DNS cce nha md died dann 38 93 DNS Forwarding saevi perc etes 38 DNS Servei bte 40 43 Domain Name Service 38 alodus ed cutting diste 100 Dst netMaSk s a bono ra 100 Dynamic Host Configuration Protocol 40 Dynamic IP routing table 97 Dynamic 32 messi abt tt i andi 30 ENG quae SS eos vertente f uum t 42 5 5 001 101 Exclusion TOMOS 33 7 30 Filterta hl E 91 Filter 91 Firewall FUNCION 32 22 105 eo ic vto ctv ccn 104 Firmware Upload with LANConfig 23 Firmware 1 23 USING 5 9 4 Firmware upload 104 ROM anten nobi dabis RR 22 ELSA icroLink Cable E G Gate Way 32 40 43 H Heap iet ru ak 90 Hierarchical IP addresses 55 M ttt rop Rt eae 50 HUD a coni rre n Dr 4 ANA 54 OM P 96 99 Nhani prse 17 Require melle dr Ree bn o 17 using ttt e bra 18 Install software 22
48. 68 110 3 W hat do the entries mean IP addresses and network masks identify the destination netw ork the distance indicates the number of routers between sender and receiver the final column indicates the router which announced this route This leaves the Time The dynamic table thus shows how old the relevant route is The value in this column acts as a multiplier for the intervals at which the RIP packets arrive A 1 therefore stands for 30 seconds a 5 for about 2 5 minutes and so on New information arriving about a route is of course designated as directly reachable and is given the time setting 1 The value in this column is ELSA MicroLink Cable Operating modes and functions automatically incremented when the corresponding amount of time has elapsed The distance is set to 16 after 3 5 minutes route not reachable and the route is deleted after 5 5 minutes Now if the router receives an IP RIP packet it must decide whether or not to incorporate the route contained into its dynamic table This is done as follows The route is incorporated if it is not yet listed in the table as long as there is enough space in the table The route exists in the table with a time of 5 or 6 The new route is then used if it indicates the same or a better distance The route exists in the table with a time of 7 to 10 and thus has the distance 16 The new route will always be used The route exists in the table The new ro
49. 8 entries and has the following layout Intranet addr S port Protocol Timeout 10 1 1 10 1234 10 The different columns have the following meaning Intranet addr IP address of the computer in the local network S port Source port for this entry Protocol Protocol used TCP UDP ICM P Timeout Time in seconds until the entry is removed from the table Setup IP router module firew all The filters for the IP packets are set in this menu The IP filters are defined in a table with the following layout Idx Active Prot Src address Src netmask S st S end Dst address WIN YES 255 255 255 255 0 0 0 0 137 139 0 0 0 0 Dst netmask D st D end Action Direct MBUcst Matches 0 0 0 0 53 53 The table fields have the following meaning Idx Unique index This entry is required to distinguish the filters The index may be four characters long and selected as desired Active Activates or deactivates the filter Prot Protocol that is to be filtered Possible entries are TCP UDP ICMP and all ELSA MicroLink Cable Description of the menu options The setting all filters out every packet from the specified source network or to the destination network Src address Src netmask A subnetwork of the local network for which the filter is valid can be entered here A source address of 0 0 0 0 means that the filter is applied to all computers A network mask of 0 0 0 0 means that the filter is applied to all networks
50. Activate the Display MIB Table item in the Manage menu of Castlerock SNM Pc ELSA MicroLink Cable Configuration modes 2 Open the corresponding table If the table is empty then empty columns will be displayed 3 Click on Edit It is now possible to display the values for every single column in the table 4 Enterthe index of the table and the value for the column to be subsequently placed and click on Setat the right hand side of the latter column A new column with the new index and the value for another column should now appear It is also possible to enter values for all columns of the row and simultaneously place all columns using Set This procedure can also be carried out using Edit M IB Vars in the Manage menu In this case click through to the table single click on the column to be placed enter the index in the field Variable Name after the name of this column and the new value in Variable Value After clicking Set a new table row should appear Error messages via SNMP trap Error or warning messages can be sent to a manager using the SNMP mechanism The SNM P agent contained in the router permits traps to be sent to up to 20 SNM P managers The IP addresses of these managers are configured in the Configuration menu under setup SNMP module IP Trap Table You can enable and disable the trans mission of trap messages using the setup SNMP module Send Traps switch The Management Information Base M
51. CM P LAN checksum errors ICM P LAN service errors ICM P Cable rx ICM P Cable tx ICM P Cable checksum errors ICM P Cable service errors Delete values ELSA MicroLink Cable Number of ICM P packets received from the LAN Number of ICM P packets sent to the LAN N umber of ICM P packets incorrectly received from the LAN Number of non supported ICM P packets received from the LAN Number of ICM P packets received from the cable network Number of ICM P packets sent to the cable network Number of ICM P packets incorrectly received from the cable netw ork Number of non supported ICM P packets received from the cable netw ork Deletes ICM P statistics Description of the menu options Status TCP IP statistics TCP statistics These statistics include the following values TCP LAN rx TCP LAN tx TCP LAN tx repeats TCP LAN checksum errors TCP LAN service errors TCP LAN connections TCP Cable rx TCP Cable tx TCP Cable tx repeats TCP Cable checksum errors TCP Cable service errors TCP Cable connections Delete values Number of TCP packets received from the LAN Number of TCP packets sent to the LAN Number of TCP packets repeatedly sent to the LAN N umber of TCP packets incorrectly received from the LAN N umber of TCP packets received from the LAN for an incorrect port Current number of TCP connections from the LAN Number of TCP packets received from the cable network Number of TCP packets sent to the cable netwo
52. DHCP server of your ELSA M icroLink Cable on the DHCP Server tab as well as the Masquerading function on the asquerading tab 4 Save the configuration with OK ELSA MicroLink Cable O Installation and configuration The ELSA M icroLink Cable is now ready for use in bridge mode Open your W eb brow ser and off you go into the W eb with a whole new sensation of speed If you can only access the Internet with a single computer while using this configuration your cable network operator may have placed a limit on the maximum number of connected computers Either ask your network operator to increase the number or configure your ELSA MicroLink Cable as a router with DHCP server and IP masquerading If necessary filters can be defined to restrict the exchange of data packets between the local network and the Internet Configuration as a router In addition to bridge mode the ELSA M icroLink Cable can also serve as an IP router In this mode the ELSA M icroLink Cable pays careful attention to the IP addresses of the computers exchanging data with the Internet The exchange of data with the Internet can thus be set up with much greater precision in this mode The DHCP server and IP masquerading functions will assist you with the administration of IP addresses in the LAN IEAS Computer workstation in IP address assignment 4 MES pe SS 1 IP address assignment 9 F 8
53. ELSA MicroLink Cable 1999 ELSA AG Aachen Germany While the information in this manual has been compiled with great care it may not be deemed an assurance of product characteristics ELSA shall be liable only to the degree specified in the terms of sale and delivery The reproduction and distribution of the documentation and software supplied with this product and the use of its contents is subject to written authorization from ELSA We reserve the right to make any alterations that arise as the result of technical development ELSA is DIN EN ISO 9001 certified The accredited T V CERT certification authority has confirmed ELSA conformity to the worldwide ISO 9001 standard in certificate number 09 100 5069 issued on J une 15 1998 Trademarks Windows Windows and Microsoft are registered trademarks of icrosoft Corp All other names mentioned may be trademarks or registered trademarks of their respective owners The ELSA logo is a registered trademark of ELSA AG Subject to change without notice No liability for technical errors or omissions ELSA AG ELSA Inc Sonnenweg 11 2231 Calle De Luna 52070 Aachen Santa Clara CA 95054 Germany USA www elsa com Aachen October 1999 No 20840 1099 Preface Thank you for placing your trust in this ELSA product With the ELSA M icroLink Cable you have chosen a modem that will open the door to the Internet for you with unparalleled speeds and rema
54. Firmw are Management gt Upload New Firmware or click directly on the Firmw are Upload button Then select the directory in which the new version is located and mark the corresponding file ELSA LANconfig then tells you the version number and the date of the firmware in the description and offers to upload the file The firmware you already have installed will be replaced by the selected release by clicking Open You also have to decide whether the firmware should be permanently activated immediately after loading or set a testing period during which you will activate the firmware yourself To activate the firmware during the set test period click on Edit Firmware Management gt Upload New Firmware ELSA MicroLink Cable Configuration modes O O TFTP W ith TFTP you can use the w riteflash command to install new firmware To send a new firmware version which for example is in the LC_1000U 130 file to a router with the IP address 194 162 200 17 you would enter the following command under Windows NT for example tftp i 194 162 200 17 put Ic 1000 130 writeflash This command sends the corresponding file to the router using the writeflash parameter Binary file transfer must be set for TFTP However many systems have the ASCII format preset This example for Windows NT shows you how to achieve this by using the parameter The device is booted up following a successful firmware upload and this activates the new firmw
55. IB A textual representation of the configuration structure the so called private M IB must be supplied with the ELSA M icroLink Cable so that the SNM P management system can access its configuration The syntax of this MIB complies with ASN 1 Abstract Syntax Notation One ISO 8824 There is usually a so called MIB compiler included with the SNMP management software This compiler converts the M IB file into a form that can be used by the manager The current ELSA M IB can be found both included with the product on CD and in the ELSA online media ELSA icroLink Cable Configuration modes ELSA MicroLink Cable Operating modes and functions Operating modes and functions This section is an introduction to the functions and operating modes of your device It includes information on the follow ing points Security for your configuration Security for your LAN IP routing Bridging DHCP server Along with the description of the individual points we will also give you information to support you as you configure your device Detailed sample configurations can be found in the W orkshop Please refer to the electronic documentation for a detailed description of all parameters and menus Security for your configuration A number of important parameters for the exchange of data are established in the configuration of the device These include the security of your network monitoring of costs and the authorizations for the indiv
56. LI Description of the menu options Protocol The protocol table also supplies valuable information on the volume of packets table transferred to the LAN or cable network These values are broken down according to the various IP protocols such as ICM P TCP UDP A protocol table might have the follow ing appearance Protocol LAN tx Cable tx tcp 14 30 udp 15 50 icmp 60 40 Status IP router statistics RIP statistics This option allows you to display the IP RIP packets received by the device These Substatistics provide you with the following entries RIP rx Number of IP RIP packets received RIP request Number of IP RIP request packets received RIP response Number of IP RIP response packets received RIP discards Number of IP RIP packets discarded RIP errors Number of damaged packets RIP entry errors N umber of erred entries in IP RIP packets RIP tx Number of IP RIP packets sent Table IP RIP Routing table of routes learned through RIP broadcast Delete values Deletes RIP statistics The associated IP RIP table contains all of the routes learned from the network The router itself maintains this table you cannot modify it manually An IP RIP table might have the following appearance IP address IP netmask Time Distance Router 2232452540 255 255 255 0 1 1 192 389 100 223 245 257 0 255 255 255 0 1 1 1192 38 9 200 ELSA MicroLink Cable Status Config statistics Description of the menu options
57. M icroLink Cable ON This LED flashes once when the power supply is switched on After the self test either an error is output by a flashing light code or the device starts and the LED remains lit Off Unit switched off power supply plugged in red 1 x short Boot procedure test and load started red flashing Display of a boot error flashing light code red Device ready for use Standby This LED shows that the unit is in stand by mode The ELSA M icroLink Cable is registered with the cable network provider in this state but there is no active connection to the local network In other words no data can be exchanged between the Internet and the LAN in this state The ELSA MicroLink Cable can be switched to this mode by configuring the function of the power switch correspondingly and then actuating this switch on the rear of the unit Cable Tx Rx These LEDs display the status of the interface to the cable network Sync Reg d Cable Tx yellow Data packet sent from the device to the Internet Cable Rx green Data packet received from the Internet Cable Sync green The device has found a channel on which it can communicate with the cable network operator s headend Cable Reg d green The registration and all required negotiations between the unit and the headend have been completed and the registration confirmed by the hea dend The unit is ready to exchange data with the Internet in this state Blink codes The Sync and Reg d LEDs
58. P configuration Check the current IP configuration of the computer under Windows 95 or Windows 98 by selecting Start gt Run gt winipcfg Among other information you can see the IP address assigned to the computer by the DHCP server and the addresses conveyed for the DNS server and gateway E IP Configuration ie Host Information Host Name ST171 DNS Servers Hybrid NetBIOS Scope Id IP Routing Enabled WINS Proxy Enabled NetBIOS Resolution Uses DNS Ethernet Adapter Information JELN K3 Ethernet Adapter Adapter Address 00 20 99 3 IPAddress 193 103 233 171 Subnet Mask 2552552550 Default Gateway DHCP Server Primary WINS Server Secondary WINS Server Lease Obtained Lease Expires Release All Renew All ELSA MicroLink Cable Lo Configuration modes Configuration modes ELSA cable modems are always delivered with up to date software in which a number of the settings have already been prepared for you It will nevertheless be necessary for you to add some information and configure them to your specific needs These settings are made as part of the configuration process This section will show you the programs and routes you can use to access the device and set it up And if the team at ELSA has produced firmware with new features we will show you how to load the new so
59. SA LANconfig on the computer that will be used to set up the device If the setup program does not start up automatically after insertion of the CD start Windows Explorer click on autorun exe on the ELSA M icroLink Cable and follow the instructions in the install program Configuring the ELSA MicroLink Cable The first time ELSA LANconfig is run the new modem is automatically detected on the TCP IP network and can immediately be configured When configuring the router with ELSA LANconfig you can use the setup wizards to quickly and conveniently guide you through the required settings ELSA MicroLink Cable Installation and configuration Quick Start Quick configurations We re sure that after you ve installed the hardware and software you ll want to get going quickly without bothering with technical details In the following sections we ll show you how to set up your ELSA MicroLink Cable quickly for the most common applications without bothering with the whys and wherefores After the preparations that you should check in any case we will introduce the configuration of the unit as a bridge and IP router Further information on the bridge and router functions can be found in the Operating M odes chapter Preparations The Internet is based on the TCP IP network protocol The individual devices in the Internet workstations servers routers etc are identified using unique IP addresses computers exchanging data on th
60. This setting an IP address registered in the Internet with a fully assigned network mask can be used for masquerading via a raw IP access With such an access an IP address is not assigned to the router by a PPP negotiation but it must have a fixed IP address registered in the Internet The netmask associated with the IP address as transmitted by the headend during the registration is displayed here The LAN side IP address for the device can be entered here The second IP address enables the device to be used as a router for two logical IP networks and also this address has a specific meaning with the use of IP masquerading In this case all computers that are in the network linked by the LAN side IP address and IP netmask are hidden behind the address assigned by the provider or the cable IP address The network mask belonging to the IP address of the local network must be entered here The default setting is 255 255 255 0 class C network If no LAN IP address has yet been specified the device responds to a default IP address the first three digits of which are identical to the first three digits of the sending device XXX XXX XXX YYY The device can then be reached by dialing the IP address XXX XXX XXX 254 ELSA MicroLink Cable Access list A ARP table Description of the menu options If such an IP address already exists in the network shut down the device using the address for the duration of the configuration and a
61. a part of the LAN of the cable network operator and forms a LAN together with the headend and all connected cable modems The cable network operator assigns the IP addresses to the participants via DHCP On the other side the cable modem forms a separate LAN with one or more connected computers DHCP can also be used to manage addresses within your own LAN The cable modem thus functions as a DHCP client and as a DHCP server W henever IP addresses of the cable modem are mentioned in the following paragraphs this is a reference to the LAN IP address of the ELSA M icroLink Cable unless something else is explicitly stated The DHCP client The cable IP address for the exchange of data in the cable network is assigned via DHCP by the network operator during registration at the headend i e the network participant has no influence on this process Apart from the IP address used by the cable modem when active on the cable network additional information is transmitted such as the cable network operator s gateway into the Internet or the time server Since this assignment via DHCP from the cable network to the cable modem is mandatory it is not necessary to configure the DHCP client Current assignments can be read at any time Status DHCP client status menu The DHCP server As a DHCP server the ELSA M icroLink Cable can manage the IP addresses in its TCP IP network In doing so it passes the following parameters to the workstation
62. ackets in the receive queue of the TFTP clients Number of packets to be forwarded to DNS or NBNS servers N umber of packets that come from DNS or NBNS ser vers and are to be forwarded to the host N a of packets to be sent masked to the Inter net Number of packets received from the Internet and have to be demasked Status M CNS statistics M CSN statistics Description of the menu options M CNS T1 timeouts 9 Number of timeouts while waiting for the upstream channel descriptor M CNS T2 timeouts 9 Number of broadcast ranging timeouts M CNS T3 timeouts 9 Number of ranging response timeouts M CNS T4 timeouts 9 Number of unicast ranging timeouts M CNS T6 timeouts 9 Number of registration response timeouts M CNS upstream channel des 9 Number of received upstream channel descriptors criptors M CNS ranging requests 9 Number of ranging request packets were sent M CNS ranging responses 9 Number of ranging response packets received M CNS ranging aborts 9 of ranging aborts M CNS registration requests 9 Number of registration request packets sent M CNS registration responses 9 Number of registration response packets received CNS SYNCS 9 Number of SYNC packets received M CNS M aps 9 Number of M AP packets received Delete values E Deletes M CNS statistics Status Init status Cable statistics Current dow nstream frequency 9 Display of the downstream frequency in Hz Channel found 9 Channel of the curre
63. adcaster continuously transmits a selection of information in the form of individual pages over the cable network The user can then choose a page by entering a number for example How ever the user is restricted to the broadcaster s selection and cannot send data back upstream Standards Two standards get around this problem The first solution accepts the restriction of the cable network to downstream transfers and handles the upstream using normal telephone lines The disadvantage is obvious it requires an additional line on the telephone network through a normal modem for example subject to telephone connect charges A standard that was successfully applied in the USA equips the cable network with suitable amplifiers and remote stations for the transfer of data back to the provider These remote stations are called headends or CM 155 Cable Modem Termination System Connections using the MCNS standard Multimedia Cable Network System no longer need an extra telephone connection Access to the Internet is thus no longer subject to time related connect charges in effect providing the user With a permanent connection to the Internet Access To clarify access to the Internet through the cable network using a simplified description let s have a look at both sides of the connection On one side we have the user who would like to connect to the Internet with a local network or an individual ELSA icroLink Cable LE Technic
64. al basics computer On the other side is the operator of the broadband cable network who would like to provide more than just radio and TV A headend can accommodate up to 2000 individual users with cable modems like the ELSA M icroLink Cable The headend functions as a multiport how ever giving every user access to the cable network at any time Unlike access through analog or ISDN modems there are no connection attempts that could fail because all of the provider s ports are already in use No further hardware is needed for the connection between the Internet user and the network operator as long as both the cable modem and the headend use the bidirectional M CNS standard On the other side the network operator has to establish a connection to the Internet He can either act as an Internet service provider ISP himself and directly establish access to the Internet or he can outsource this task on to another ISP or an online service Computer workstation in LAN En 2 pa 4 Mess ES z Server with Headend ELSA M icroLink Hub DHCP Cable Network of the cable netw ork Cable TV net operator Work Network of the user This connection to the backbone is of little relevance to the user However the greater the performance of the network operator s backbone line the quicker the users receive information from the Internet Registration in the cable netw ork In comparison to other data transfer media
65. also checks whether the address selected is still available in the local network As soon as the uniqueness of an address has been established the requesting computer is assigned the address found Netw ork mask assignment The network mask is assigned in the same way as the address If a network mask is entered in the DHCP module this mask is used for the assignment Otherwise the network mask from the TCP IP module is used Broadcast address assignment Normally an address yielded from the valid IP addresses and the network mask is used for broadcast packets in the local network In special cases however e g when using subnetworks for some of the workstation computers it may be necessary to use a different broadcast address In this case the broadcast address to be used is entered in the DHCP module The default setting for the broadcast address should be changed by experienced network specialists only DNS server assignment The addresses of the DNS servers are negotiated and entered during the registration at the headend Default gatew ay assignment The router always assigns the requesting computer its own IP address as a gateway address If necessary this assignment can be overwritten with the settings on the workstation computer Period of validity for an assignment The addresses assigned to the computer are valid only for a limited period of time Once this period of validity has expired the computer can no longer
66. are switch directly If an error occurs during the upload w rite error in the flash ROM TFTP transmission error or similar the device also boots and FirmSafe activates the previous firmware The configuration remains in operation It will only be possible to configure the device locally i e via the outband interface if it is switched off during TFTP upload The device will expect a firmware upload via the serial port when it is switched back on You should therefore be sure to carry out a firmware upload only when you have a secure stable connection With TFTP other configuration commands can also be executed The syntax is best demonstrated with the following examples tftp 10 0 0 1 get readconfig filel Reads the configuration from the device with the address 10 0 0 1 and saves it as in the current directory tftp 10 0 0 1 put filel writeconfig Writes the configuration from file1 to the device with the address 10 0 0 1 tftp 10 0 0 1 get dir status verb file2 Saves the current connection information in file2 Configuration using SNMP General The Simple Network Management Protocol SNM P V 1 as specified RFC 1157 allows monitoring and configuration of the devices on a network from a single central instance This instance is commonly termed the M anager while the devices become Agents The structure permitted for SNM P information exchange is relatively simple A manager can access all SNM P capable devices and s
67. be transferred through a LAN by packing it in a LAN packet and adding the IP protocol type to it Because of the IP entry the LAN interface at the receiving host recognizes that the LAN packet contains an IP packet extracts it and processes it as an ordinary IP packet In this way IP packets and packets of other network protocols like IPX can be transferred simultaneously through the same LAN without conflicts this is why a LAN is called multiprotocol capable To an IP host a LAN behaves as if it were an independent network with a router The hosts gives the packets to the LAN which handles the further distribution of the data packets This is why only IP addresses from the numerical space of the specific network should be used for the internal communication of the hosts in a LAN through the IP protocol IP host IP host in the LAN in the LAN e IP host in the p LAN with router function 1 distributes the LAN packets E To a router in the LAN a host in its own LAN seems to be located behind another router So the task for the router is very simple all it has to know for operating in the IP netw ork are the IP addresses of the directly connected hosts and of the available networks and subnets ELSA MicroLink Cable ARP Technical basics E i e all it has to remember is the network address and the netmask of the subnet in the LAN IP host IP host in the LAN in the LAN 19 19
68. ble The use of inverse masquerading makes services e g a file server selectively visible in the Internet by entering specified ports in the service table in the IP network while all other services and computers remain invisible from the local network see also IP Masquerading NAT on page 31 The service table also called the static masquerading table can contain up to 16 entries and has the following layout D port Intranet addr 20 101110 21 101110 The different columns have the following meaning D port Destination port for the particular entry Intranet addr Destination IP address for the computer in the local network Through this assignment it is possible for example to address the relevant service directly via telnet Enter the IP address of the router and attach the port number separated by a colon to the address You can use the command ELSA MicroLink Cable Table masquerading Description of the menu options L telnet 192 38 50 100 27 to connect directly to a news server that can be reached via a router with the IP address 192 38 50 100 W ith IP masquerading the IP addresses of computers in the local network are rendered invisible to external devices by means of a conversion of addresses and ports in the router The dynamic masquerading table displays the IP addresses from the local network that the router is currently masking The dynamic masquerading table can contain up to 204
69. can display the various phases of the cable modem registration through combined blink codes thus offering configuration troubleshooting information The meanings of the specific blink codes SYNC REG d has been achieved so What is the modem trying to do ar off off TE search with 64 256QAM chan ne 1 pulse off QAM lock FEC lock 2 pulse off FEC lock TRC lock on off TRC lock initial ranging on 1 pulse initial ranging DHCP on 2 pulse DHCP ToD on 3 pulse ToD Configuration file on 4 pulse Configuration file Registration on on Registration ELSA MicroLink Cable Introducing the ELSA M icroLink Cable LAN Tx Rx These LEDs show the corresponding network controller status LAN Coll Link LAN tx yellow Data packet sent from the device to the LAN LAN Rx green Data packet received from the LAN LAN coll red Sending collision LAN Link green Connection to LAN is established and ready N ow turn the whole thing around and take a look at the rear Beginning again on the left hand side you have Connector for the cable TV network CATV Reset switch performs a hardware reset Factory Default button the unit s factory defaults are restored after holding this button for approx 15 seconds 10Base T network connection Node hub selector switch Connection for power supply unit 92000 868 On standby switch ELSA MicroLink Cable Introducing the ELSA M icroLink Cable O Shared media M ultiple
70. cture of the cable network The headends that have to be additionally integrated into the network with their restriction to around 2000 participants results in further area limitations ELSA MicroLink Cable 6 Introducing the ELSA M icroLink Cable Proxy Stand in Network operators can take advantage of this structure to provide regional content in addition to the Internet This can be accomplished by setting up W eb servers that do not need to be accessible from the Internet These can then be used for special information services for network participants such as the programs of local cinemas regional news information for clubs and special interest groups and so on essentially everything that is of interest to the regional cable network participants but that might be superfluous on the W eb Proxy servers The network operator can also use local servers to speed up access to the Internet These proxy servers are used for the intermediate storage of information from the Internet Every page requested from the Internet by participants in the local cable network section is stored in this proxy server for a specific period of time As a rule the storage period on the proxy server is determined by the cable network operator If another participant requests the same page the proxy server can serve the page directly without having to find it on the Internet first This is generally beneficial for example by speeding up downloads consid
71. d may be selected freely within certain ranges The IP router can check the source and destination ports of data packets using the TCP or UDP protocols It can then deduce the purpose of the data from these ports For example FTP accesses or Telnet sessions can be identified The appropriate filter table can be used to determine that certain data is not to be transferred from the LAN to the remote station Data for particular ports can also be blocked from entering the LAN in the same way In addition to the definition of the port range and the associated protocols the filter table can be used to determine whether the data packet concerned will be accepted or rejected Both interfaces of the cable modem for the cable network and for the LAN can be set separately for incoming and outgoing data transfer This filter table can be found in the configuration tool ELSA LANconfig in the configuration section on the Filter tab orinthe Setup IP router firewall menu The hiding place IP masquerading NAT PAT One of today s most common tasks a for cable modem is connecting the numerous workstation computers in a LAN to the ultimate network the Internet Everyone should have the potential to access the WWW from his workstation and be able to fetch bang up to date information for his work ELSA icroLink Cable Operating modes and functions But this provokes objections from the network manager responsible for the s
72. d computers all Internet addresses must also be unique Bodies exist that manage and distribute these publicly accessible addresses Since the number of IP addresses theoretically available is limited these distributing bodies charge high rates for the addresses Private address range of IP addresses are reserved for use free of charge private address spaces so PACES that companies do not have to purchase individual IP addresses for every workstation In a closed network these addresses can be used as desired in a private network or company for example The same address can be used in other closed networks e g in different companies but the addresses within one network must be unique However these reserved IP addresses must not be made public on the Internet Only those devices in a network that are connected to a public network e g the router at the interface to the Internet must have a registered IP address The allocation of IP addresses by the IANA Internet Assigned Numbers Authority permits the following address ranges to be used for private use IP address Netmask Remark 10 0 0 0 255 0 0 0 10 networks All IP addresses beginning with 10 and whose mask begins with 255 belong to the address range reserved for private use 172 106 0 0 255 240 0 0 AIL IP addresses beginning with 172 16 172 31 which are associ ated with a net mask greater than or equal to 255 240 0 0 are within the address range reser
73. dapter Documentation CD containing ELSA LANconfig and electronic documentation Computers to be connected to the Internet using this device must fulfill the following requirements Any operating system that supports the TCP IP network protocol such as Windows 95 Windows 98 Windows NT 4 0 05 2 Linux BeOS Windows 95 Windows 98 or Windows NT 4 0 and a CD ROM drive on the computer on which you would like to install the ELSA LANconfig configuration software Ethernet netw ork adapter TCP IP network protocol installed and bound to the network adapter First we will show you how to connect your new ELSA M icroLink Cable how to install the ELSA LANconfig configuration software and perform the initial configuration The unit will then be ready to connect your computer or network to the Internet If this is all going too fast for you or you re not familiar with the technical terms you can also find further information in this documentation such as detailed descriptions of the unit and its functions sample configurations descriptions of the software glossaries etc This unit is designed to be connected to the broadband cable TV network The connection is made using the supplied coaxial cable or the appropriate adapter ELSA MicroLink Cable EJ Installation and configuration Q O First Steps 1 Give itsome power First give your device the power it needs through the power supply unit Onto the net Connect the unit
74. dress IP netmask 192 234 222 0 255 255 255 0 With this entry all IP addresses in the class C network 192 234 222 0 are authorized to use internal functions of the router This option allows you to display the ARP table ARP cache which is managed automatically for the purpose of mapping IP addresses onto physical terminal addresses Individual entries can be removed from this table but no new entries can be entered manually ELSA MicroLink Cable GELI Description of the menu options ARP aging min TCP aging min TCP max conn Operating Q The entries in the ARP table might for example have the following appearance if different devices with different IP addresses 192 168 139 20 192 168 130 30 communicated with the router IP address Node ID Last access Connect 192 168 130 20 0000 0717860 6780443 tics local 192 168 130 30 0800091 4 6214514 tics This option allows you to enter a time from 1 to 99 minutes the end of which the ARP table is automatically updated i e all IP addresses that have not been accessed since the last automatic update are removed The default setting is 15 minutes If data transfer stops during a TCP connection to the router e g if the user does not enter any more data during the remote configuration it will automatically release the TCP connection on expiry of the time entered here Possible settings are from 1 to 99 minutes The default setting
75. ds Specified computers and networks may be simultaneously subjected to targeted filtering while others pass the router unfiltered The tables are processed from top to bottom As soon as a matching filter is found the packet is handled accordingly Setup SNM P module This menu allows you to enter settings for configuration of the device via SNMP The menu has the follow ing layout SNMP module SNMP module settings Send Traps Switch for issuing SNM P traps IP Trap Table Table with 20 destination addresses for trap messages Administrator r Device administrator Location Device location This entry controls trap output No Yes Specifies the IP addresses to which the trap messages will be sent Administrator s name Device location Setup DHCP server module This menu allows you to enter settings for the DHCP server The menu has the following layout DHCP server module DHCP server settings Operating amr Switch for activating the DHCP module Start address pool my Start address for the address pool End address pool End address for the address pool Netmask my Network mask for the address pool Broadcast address cy Broadcast address for the LAN M ax lease time minute s aximum period of validity for the address assignment via DHCP Default lease time minute s Default period of validity for the address assignment via Table DHCP Table of current assignments via DHCP On The
76. e Internet therefore must have the TCP IP network protocol installed and must be assigned a valid IP address IP addresses can either be manually entered permanently for each computer or assigned automatically by a different computer a so called DHCP server Your cable network operator has such a DHCP server and one is also contained in the ELSA M icroLink Cable itself For this quick start we prefer using the automatic assignment of an IP address by a DHCP server The cable network operator s DHCP server will be used when configuring the unit as a bridge in router mode the integrated DHCP server of the ELSA M icroLink Cable will be used The following settings are required regardless of the operating mode you intend to use with your ELSA M icroLink Cable Install the TCP IP network protocol on all computers on the network Activate the automatic assignment of IP addresses via DHCP for the workstations generally the default setting Just how you do that will be explained in section How to set up the workstation computers towards the back of this chapter Configuration as a bridge Bridge mode is the simplest configuration for the ELSA M icroLink Cable In this mode the unit does not take IP addresses into consideration and transfers all data that is not destined for workstations in the local network directly to the Internet In the opposite direction all data coming from the Internet for a specific computer in the local network is
77. e changed by the cable network operator as operation within the cable network will be impossible otherwise The relevant menu items are therefore not covered in this documentation Setup LAN module This menu item displays the connection values relevant for the local network The menu has the following layout LAN module LAN settings Connector 9 Network connection Node ID 9 M AC layer address of the device This option allows you to display the router s own Ethernet address The value displayed here was set at the factory and cannot be changed The Ethernet address is displayed as a 12 digit hexadecimal value with the first six digits 00 057 standing for an ELSA device ELSA MicroLink Cable 2 Description of the menu options Operating Q Bridge table Q Broadcast M ulticast Setup Bridge module This menu allows you to select the settings necessary for bridge mode The menu has the follow ing layout Bridge module Bridge settings Operating Bridge active or inactive Bridge table Displays bridge table LAN config Settings for the LAN side Cable config Settings for the cable side This option allows you to activate or deactivate the bridge In the default configuration the bridge is activated If the device is used just as an IP router connection the bridge should be deactivated This option allows you to display the entries in the current bridge table The
78. e desired information from this server If no DNS server has been entered in the cable modem it tries to reach the network operator s DNS server to retrieve the IP address associated with the name The address of the DNS at the network operator is transferred during the registration of the cable modem by the headend This procedure does not require you to have any knowledge of the DNS server address Entering the LAN IP address of the cable modem as the DNS server for the workstation computers is sufficient to enable name associations This procedure also automatically updates the address of the DNS server Your local network always receives the most current information even if for example the provider sending the address changes the name of his DNS server or you change to another provider Bridging A bridge connects two or more LANs in such a way that they appear to be a single large network When bridging via cable modems the LAN of the cable network operator with the headend is on one side and the LAN of the network participants with the cable modem and the local workstations on the other LAN ofthe cable network ope further connected cable LAN ofthe user rator modems Cable TV net ELSA M icroLink Hub Work Cable In the bridge operating mode the ELSA M icroLink Cable transfers all data to computers without locally assigned M AC addresses between the local network or another local area network LAN ora workstat
79. e in the first column to its current value Example You want to delete the 3rd row from following IP routing table IP address IP netmask Router name Distance 192 168 0 0 255 255 0 0 0 0 0 0 0 172 16 0 0 255 240 0 0 0 0 0 0 0 10 0 0 0 255 0 0 0 ROBERT 0 224 0 0 0 224 0 0 0 0 0 0 0 0 The entry 10 0 0 0 i e the first cell of the third row is amended in the manager to its current value i e to 10 0 0 0 and the Set command is sent off The SNMP SetRequest now contains the command to amend the first cell of the third row to 10 0 0 0 The SNM P software recognizes that this assignment to the index is redundant and interprets it as a delete command Appending rows to tables using SNMP There are two ways of inserting rows in a table Using the set command will result in a new row through setting a new index entry By using the command in the syntax someTable 1 2 2 row with index 2 will be generated in the table someTable with the entry xyz in its second column The 1 after the table name is constant for this command and stands for someEntry in the SNM P Syntax When using SNM P managers that do not allow the entry of index values it is possible to amend any existing index entry to the new index value of the new row The row which has been used as the source for the amendment will itself remain unchanged If we take Castlerock SNMPc as an example the first possibility can be realized as follows D
80. ecurity of data on the company s network Every workstation computer the WWW Surely this means that anyone can get in from outside Not true IP masquerading provides a hiding place for every computer while connected with the Internet Only the router module of the unit and its IP address are visible on the Internet The computers in the LAN then use the router as a gateway so that they themselves cannot be detected To do this the router separates Internet and intranet as if by a wall Therefore IP masquerading is also called a firewall function For further information see the IP Routing IP masquerading section IP routing This chapter describes the function of the cable modem as an IP router Whenever the IP router or simply the router is mentioned in the next paragraphs this is a reference to the corresponding operating mode of the cable modem O An IP router works between networks which use TCP IP as the network protocol This only allows data transmissions to destination addresses entered in the routing table This chapter explains the structure of the IP routing table of an ELSA router as well as the additional functions available to support IP routing The IP routing table Use the IP routing table to tell the router which remote station which other router or computer it should send the data for particular IP addresses or IP address ranges to This type of entry is also known as a route since it is used to
81. erably How ever when calling up information subject to frequent changes such as stock prices accessing the current W eb page is usually a must In such a case the version of the page stored on the proxy server can already be out of date or incorrect If this could be relevant to you please check with your network operators whether they deploy proxy servers Clicking the Refresh button will download the current information directly from the Internet however ELSA MicroLink Cable A Introducing the ELSA M icroLink Cable CE conformity and FCC radiation standard CE This equipment has been tested and found to comply with the limits of the European Council Directive on the approximation of the laws of the member states relating to electromagnetic compatibility 89 336 EEC according to EN 55022 class B and EN55024 FCC This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to Part 15 of the Federal Communications Commission FCC Rules Operation is subject to the following two conditions This device may not cause harmful interference and Q This device must accept any inteference received including interference that may cause undesired operation The FCC ID of this device is GM LCABLE CE and FCC These limits are designed to provide reasonable protection against radio frequency interference in a residential installation This equipment generates uses and can radiate
82. ervices agents on the network The access rights are controlled via Communities ELSA MicroLink Cable Configuration modes SNM P V 1 has only a very limited set of commands at its disposal as the table below shows Command Target Source Function GetRequest M anager Agent retrieves information from the agent GetNextRequest M anager Agent retrieves the information contained in the following M IB from the agent SetRequest M anager Agent modifies a setting in the agent GetResponse Agent M anager returns the queried value to the man ager Trap Agent M anager reports on an error or special status These commands can be used for central monitoring and configuration of SNM P capable devices on a network The SNMP capabilities of the agents are specified in so called IBs M anagement Information Bases The firmware of ELSA routers includes an implementation for an SNMP V 1 agent in accordance with RFC 1157 A part of M IB 2 and a private M IB included in the product as a separate file are supported This M IB must be loaded and translated by an SNMP manager HP OpenView for example to allow you to manage a device completely using SNM P menus and parameters of the remote configuration will then be available to you on a single branch of the SNM P management tree Accessing tables and parameters using SNMP Any of the tables and parameters can be read and modified as necessary via the SNM P interface This als
83. eting Example Inc 2 The router in the development division receives the packet and extracts from the address the information that it is directed at the marketing division of Example Inc Since it is itself part of Example Inc but not of the marketing division it passes the packet on to the router in the superordinate network 3 The router at the Example Inc receives the packet and extracts from the address the information that it is directed at Example Inc Since it is itself part of Example Inc it takes a closer look at the address to find the name of the division It then passes the packet on to the router in the marketing division where the packet is passed on to the recipient Expansion through local netw orks Up to now we have only considered the point to point connections However many computer networks are based on multipoint cabling such as Ethernet All computers connected to the same network can then receive the signals of all other computers so called broadcast transfer to a shared medium If several computers are sending simultaneously the superimposed signals are destroyed A variety of access methods such as CSMA CD or Token Ring are implemented the MAC layer Media Access Control M AC for the avoidance and resolution of such collisions The connection of all computers communicating through a shared medium using a MAC protocol is called a LAN A LAN forms an independent network and is subordinate to the IP
84. figure fixed IP addresses on your workstation computers Start gt Settings gt Control Panel Network gt TCP IP gt Properties gt IP Address gt Specify an IP address Allocate unique IP addresses e g from a reserved address space The workstations can be assigned the addresses 10 1 1 2 to 10 1 1 253 for example the ELSA MicroLink Cable the address 10 1 1 1 all with the netmask 255 255 255 0 Ensure that the address intended for the ELSA M icroLink Cable i e 10 1 1 1 is available by opening a DOS box and entering the command ping 10 1 1 1 If you do not receive a reply to this request the address is probably still unused ELSA MicroLink Cable Installation and configuration Otherwise address conflicts with other users in your cable network may result when 2 Assign fixed IP addresses in router mode with activated IP masquerading only using router mode without IP masquerading or bridge mode Specifying the gateway and the DNS server not necessary if using DHCP Enter the LAN IP address of the ELSA M icroLink Cable in your own local network as the gateway and domain name server DNS server in the individual workstations Start gt Settings gt Control Panel gt Network gt TCP IP gt Properties Gatew ay and DNS Configuration You must also specify a host name forthe DNS configuration Use the name of the PC for reasons of consistency which for example could be the same as the user name Checking the I
85. follow ing display for the trace Status Status messages for the connection Error Error messages for the connection IP router IP routing IP RIP IP Routing Information Protocol ICM P Internet Control M essage Protocol ARP Address Resolution Protocol M asquerade Processes in the masquerading module Dynamic Host Configuration Protocol This combination brings up the follow ing display for the trace command All All trace outputs Display Status and error outputs ELSA icroLink Cable Configuration modes O This combination brings up the following display for the trace command TCP IP IP Rt IP RIP ICM P and ARP outputs Time Displays the system time in front of the actual trace output Source Includes a display of the protocol that has initiated the output in front of the trace Any appended parameters are processed from left to right This means that it is possible to call a parameter and then restrict it Examples This code in combination with the trace causes the follow ing trace Displays all protocols that can generate outputs during the configuration and the status of each output ON or OFF trace Switches on all trace outputs trace all icmp Switches on all trace outputs with the exception of the ICM P protocol trace time Switches off the system time output before the actual trace output You will find notes on the interpretation of t
86. for communication with the outside world using the ISDN In the same way ELSA cable modems have an IP address for their own network and another IP address for the exchange of data with the cable network An IP address contains the address of the network as well as that of the host The network address is the same for all hosts on one network whereas the address of the host is exclusive and unique to the network A router for example can have more than one IP address each one unique to the network How then can you differentiate between the part that determines the network and the part that identifies the host With the netmask You know what masks are they cover up one part of something and only allow a different part to be visible This is exactly how a netmask operates It is a number which is identical in structure to the IP address i e 32 zeros or ones The netmask usually starts with ones at the beginning and ends with zeros The zeros at the end thus cover the part of the IP address which does not belong to the network address Examples This address win bytes looks like this in bits IP address 192 168 120 253 11000000 10101000 01111000 11111101 Netmask 255 255 255 0 11111111 11111111 11111111 00000000 Network address 192 168 120 0 11000000 10101000 01111000 00000000 The same IP address this time with another netmask This address win bytes looks like this in bits IP address 192 168 120 253 110
87. fore the DHCP server can assign IP addresses to the computers in the network it first needs to know which addresses are available for assignment Three options exist for determining the available selection of addresses The IP address can be taken from the address pool selected start address pool to end address pool Any valid addresses in the local network can be entered here If 0 0 0 0 is entered instead the DHCP server automatically determines the addresses start or end from the LAN IP address settings in the TCP IP module If the cable modem has no LAN IP address of its own the device will go into a special operating mode It then uses the IP address 10 0 0 254 for itself and the address pool 10 x x x for the assignment of IP addresses in the network In this state the DHCP server only assigns IP addresses and their validity to the computers in the network but not the other information If only one computer in the network is booted and requests an IP address via DHCP with its network settings a device with an activated DHCP module will assign this computer an address A valid address is taken from the pool as an IP address If the computer was already assigned an IP address at some point in the past it requests this same address ELSA MicroLink Cable O Operating modes and functions and the DHCP server attempts to reassign it this address if it has not already been assigned to another computer The DHCP server
88. ftware The user friendly method inband Using inband configuration allows any computer on the cable network or LAN to access the router However this is only possible if the router permits it as access from the WAN or LAN can be restricted or completely blocked by the IP access list Inband configuration requires the use of either telnet supplied with most operating systems or the ELSA LANconfig configuration program for Windows ELSA LANconfig is supplied with your device You can always obtain up to date releases from our online media Requirements for inband configuration TCP IP or TFTP are used to make configurations using telnet or ELSA LANconfig The TCP IP protocol must therefore be installed on the computer being used and your cable modem must be given an IP address which you will then use when addressing it A device that has not been configured yet will respond to the IP address XXX XXX XXX 254 in which the Xs are placeholders for the network address in your LAN If the computers on your network have addresses such as 192 110 130 1 then you will be able to address the router using 192 110 130 254 If a computer with the address XXX XXX XXX 254 is already active on your network shut down the computer with this IP address before continuing Give the device a new LAN IP address as soon as you have established a connection to it using ELSA LANconfig or telnet Alternatively addresses can be managed by the DHCP server If iti
89. hat the address has already been assigned to another computer Unfortunately the DHCP server has no means of obtaining additional information on this computer status A computer has informed the DHCP server that it has a fixed IP address This address can no longer be used dynamic The DHCP server assigned an address to the computer ELSA icroLink Cable Operating modes and functions ELSA MicroLink Cable Dow nstream Transfer of data from the provider to the Internet user Upstream Transfer of data from the Internet user to the provider Technical basics Technical basics This chapter is a short introduction into the technology used by your device Network professionals will find themselves just skimming these pages but novices will find this section to be very helpful for understanding the technical terms and processes Cable modem technology The cable modem belongs to a new promising generation of Internet access technology This device differs from conventional analog and ISDN modems in that it communicates via the broadband radio and cable TV available in nearly all households rather than the usual telephone lines This cable is well suited for the transfer of large volumes of data Up to now the one way flow of data from the provider to the user dow nstream has been a problem for such applications however Videotext uses this downstream data transfer the provider in this case the television bro
90. his case obtain an updated ELSA LAN config version from our online sources Lock minutes This entry has two meanings It indicates how long the access is blocked if the log in block has been activated It also sets the period after which the device forgets all prior login errors Language This option allows you to select whether you will use the German or English version of the software for performing the configuration Firmware This menu allows you to display various firmware parameters and to initiate a firmware upload Firmware Display and keyboard settings Version table Displays hardware releases and serial numbers for the cable modem Table firmsafe Information on the two firmware versions stored in the device and on the bootloader M ode firmsafe amy Firmware activation mode ELSA MicroLink Cable Version table Table firmsafe M ode firmsafe Description of the menu options Firmw Display and keyboard settings Timeout firmesafe Time in minutes required to test new firmware Test firmw are Em Tests the inactive firmware Firmware upload a Initiates a firmware upload The version table displays the firmware version and serial number of the device lfc Module Version Serial number lfc M icroLink Cable 1 00 22 03 99 0317 000 005 This table provides the following details for the two firmware versions stored in the device the position in memory 1 or 2 status information active or inact
91. idual network users Needless to say the parameters that you have set should not be modified by unauthorized persons The ELSA MicroLink Cable thus offers a variety of options to protect die configuration Password protection The simplest option for the protection of the configuration is the establishment of a password As long as a password hasn t been set anyone can change the configuration of the device The password input field can be found in the configuration tool ELSA LANconfig in the M anagement configuration section on the Security tab The password prompt can be activated in a terminal or telnet session in the setup Config Module passw prompt menu In this case the password itself is set with the command passwd Login barring The configuration in the ELSA M icroLink Cable is protected against brute force attacks by barring logins A brute force attack is the attempt of an unauthorized person to crack ELSA icroLink Cable Operating modes and functions a password to gain access to a network a computer or another device In order to do so a computer can for example go through all the possible combinations of letter and numbers until the right password is found As a measure of protection against such attacks the maximum allowed number of unsuccessful attempts to Login can be set If this limit is reached the access will be barred for a certain length of time These parameters apply globally to a
92. in online permanently The highest quality standards in manufacturing and stringent quality control are the basis for high product standards and consistent product quality This documentation contains the follow ing chapters Introducing the ELSA M icroLink Cable Installation and configuration Configuration modes Operating modes and functions Technical basics Technical reference Appendix Our online services Internet server www elsa com are available to you around the clock should you have any queries regarding the topics discussed in this manual or require any further support In the Support file section under Know How you can find answers to frequently asked questions FAQs The KnowledgeBase also contains a large pool of information Current drivers firmware tools and manuals can be downloaded at any time The KnowledgeBase can also be found on the CD Just open the file isc Support M ISC ELSASIDE index htm Content Content Introducing ELSA MicroLink Cable ssis 1 The ELSA M icroLink Cable takes the stage 1 W hat does the unit look like to RM Rt 1 Node or EE TE E 3 The highlights of the ELSA M icroLink Cable 4 Iur 4 Internet at all times always online 5 ore than Eon piede citi dett 5 conformity and FCC radiation Standard
93. ion itself If the router cannot return the address of the appropriate router to the workstation via IM CP it will forward the data to the corresponding router itself see also Local Routing Since this setting increases network utilization in the LAN the default setting is Off Setup IP router module Routing method The router offers two methods for IP routing which can be separately set for IP and ICM P packets Both methods are based on the evaluation of the field Type of service in the IP header The menu has the following layout Routing method Routing method settings Routing method Routing method for IP packets ICM P routing method Routing method for ICM P packets amy This option allows you to define the routing method used for IP packets If you select Normal all IP packets are handled in the same way as per the routing specifications of the Internet protocol If you select Type of service IP packets are placed in the urgent queue or reliable queue depending on the contents of the Type of service field All other packets are placed in the normal send queue In this way transmission is guaranteed provided that it is possible This option allows you to define the routing method used for ICM P packets If you select Normal the ICM P packets are handled like any other IP packets as the routing specifications of the Internet protocol If you select Reliable all ICM P packe
94. ion on one side and the cable network on the other side The bridge thus learns on its own which M AC addresses are located on its own network and which are located on the other side After a very high level of data traffic that occurs during the initial negotiations between the two LANs the network load drops sharply W hen receiving data from the cable network the bridge in the cable modem uses the M AC addresses to determine whether the data is destined for its own LAN The bridge will only accept data packets that are addressed to M AC addresses in its LAN ELSA MicroLink Cable Operating modes and functions W hat the filter options You may not always wish to transfer all data M uch of the data which is bouncing around inthe LAN is of no interest to remote networks or computers You can thus block transfer of the following data packets via the bridge Broadcast packets Data directed at all devices accessible in a network setup Bridge Module LAN config Broadcast M ulticast packets Data which is transferred to all devices accessible in a group Setup Bridge Module LAN config Multicast Special filter lists which exclude certain addresses from a transmission or only allow certain addresses can be set up to handle this data The bridge filters differentiate here between destination and source addresses You can first establish for both address types whether the associated table contains the addresses to which data is
95. is 15 minutes The maximum number of allowable connections possible at the same time can be set here DEFAULT setting is 0 meaning the same as any number Setup IP router module This section describes the functions of the cable modem as an IP router References in the following text to routers thus refer to the cable modem in its IP router operating mode This menu allows you to enter settings for the IP router module The menu has the following layout IP router module IP router module settings Operating r Activates or deactivates the IP router module IP routing table Router table for IP network and remote station assignment Loc routing Activates deactivates local routing Routing method Routing method for IP packets RIP config iz Settings for IP RIP operation M asquerading m Settings for IP masquerading Firewall an Settings for firewall functions This option allows you to activate or deactivate the IP router module In the default configuration the IP router module is activated Activating the IP router module also activates the TCP IP module ELSA MicroLink Cable Description of the menu options 5 IP routing table The routing table can contain maximum of 128 entries of destination network addresses or direct IP addresses with netmasks and the names or IP addresses of other local routers Alternatively you can enter a setting by means of which packets to specific destina
96. is then taken from the IP address pool the computer was already assigned an IP address at some point in the past it requests this same address and the DHCP server attempts to reassign this address if it has not already been assigned to another computer The DHCP server also checks whether the address that is to be assigned to the computer is unique in the local network It does this by issuing an ARP request to the address If the ARP request is answered the DHCP server begins the procedure again with a new address As soon as the uniqueness of an address has been established the requesting computer is assigned the address found The network mask is assigned in the same way as the IP address The system either assigns the network mask entered in the DHCP module or uses the network mask that belongs to the local network determined during address assignment The broadcast address is assigned in the same way as the IP address The system either assigns the broadcast address entered in the DHCP module or uses the broadcast address that belongs to the local network determined during address assignment Here you can enter the maximum period of validity that the DHCP server assigns a host The DEFAULT value of 6000 minutes equals approximately 4 days ELSA MicroLink Cable Default lease time minute s Table DHCP Description of the menu options Here you can enter the period of validity that is assigned if the host makes no re
97. ive the version number the date the size and the index Sequential number Position Status Version Date Size Index 1 Inactive 1 60 23061999 690 6 2 Active 1 60 30061999 692 7 3 lt loader gt 1 60 07061999 64 0 Enter the following command to activate an inactive firmware version set lt position number gt active Only one of the two firmware versions stored in the device can be active at any one time When new firmware is loaded the inactive firmware is overwritten You can decide which firmware will be activated after the upload immediate The first option is to load the new firmware and activate it immediately The following situations can result The new firmware is successfully loaded and then operates as desired Everything is then in order However if the new firmware does not operate correctly it may not be possible to communicate with the device after the restart If an error occurs during the upload the device automatically reactivates the previous firmware version and reboots the device login To prevent problems caused by defective firmware the second option will load the firmware and start it immediately n contrast to the first option the firmsafe will wait until it has successfully logged on via telnet The new firmware will only be permanently activated when the login occurs successfully within the time set under Timeout firmsafe ELSA MicroLink Cable ni Description of the me
98. ll configuration options telnet TFTP ELSA LANconfig and SNMP If barring is activated on one port all other ports are automatically barred too The following entries are provided in the configuration tool ELSA LANconfig for configuring login barring in the anagement configuration area on the Security tab or under Setup Config Module inthe menu Lock configuration after Login errors Lock configuration Lock minutes Access control via TCP IP Access to the internal functions of the devices through TCP IP can be restricted using a special filter list Internal functions in this case means Telnet or TFTP sessions to configure the ELSA LANconfig This table is empty by default and so access to the router can therefore be obtained by TCP IP using Telnet or TFTP from computers with any IP address The filter is activated when the first IP address with its associated netw ork mask is entered and from that point on only those IP addresses contained in this initial entry will be permitted to use the internal functions The circle of authorized users can be expanded by inputting further entries The filter entries can describe both individual computers and whole networks The access list can be found in the configuration tool ELSA LANconfig in the TCP IP configuration section on the General tab or in the Setup TCP IP Module Access List menu Security for your LAN You certainly would not like any outsider to access
99. ly handling of the system software by allowing different firmware versions to be read in It also allows devices to be retrofitted with all future options ELSA MicroLink Cable
100. m the LAN Number of data packets sent to the LAN Number of filtered data packets by the LAN Number of broadcasts received from the LAN Brg LAN multicasts Number of multicasts received from the LAN BRG Cable rx BRG Cable tx BRG Cable filters BRG Cable broadcasts BRG Cable multicasts Number of data packets received from the cable network Number of data packets sent to the cable network Number of filtered data packets from the cable network Number of broadcasts received from the cable network Number of multicasts received from the cable network Brg addresses Number of addresses currently known Brg address disc Number of discarded CPEs Brg CPE addresses Table bridge Number of CPEs permitted by the network operator Q jl Displays bridge filter table Delete values Em Deletes bridge statistics The bridge table provides information on the M AC addresses known to the bridge the time when the last packet was received from this device specified in tics and whether the relevant device is local or remote This table is for internal bridge module use only and cannot be modified manually Node ID Last access Forw ard Flag 00 0570308 1 396442 tics local 00 0570308 2 29442 tics remote ELSA MicroLink Cable Description of the menu options Status TCP IP statistics The TCP IP related statistics are shown here broken
101. menu options The operating time of the router since it was last started is displayed here in days hours minutes and seconds Status Current time This displays the current device time transferred by the headend Status Cable statistics This option allows you to display the various statistics parameters for the cable network port A large number of values related to the data volume transferred provide you with useful information on cable port load errors that have occurred and the internal resources of the cable modems that are available in the current operating state The Status cable statistics menu has the following layout Cable statistic s Running status displays Cable tx discarded Cable heap packets Cable queue packets Cable queue errors Cable tx M AC queue pak kets Cable rx M AC queue pak kets Cable rx fifo full Cable resp bandwidth requests Cable rx overflows data packets Cable rx overflows M sg packets Cable rx CRC mistake pak kets Cable rx CRC mistake M CNS header Cable tx data packets Cable rx data packets Cable tx msg packets Cable rx msg packets ELSA MicroLink Cable EO EO EO Kio KIO Ho mo Ho Ho Number of packets discarded due to an error lack of resources Number of buffers available Number of buffers in use Number of packets discarded due to a lack of buffers Number of buffers to be sent in the MAC chip Number of buffe
102. nce the last local or found by ARP request address access in tics remote ELSA MicroLink Cable Description of the menu options Status TCP IP statistic s IP statistics These statistics include the following values IP LAN rx IP LAN IP LAN checksum errors IP LAN service errors IP LAN fragmentation errors IP Cable rx IP Cable tx IP Cable checksum errors IP Cable service errors IP Cable fragmentation errors IP Cable rx disconnect Delete values Number of IP packets received from the LAN Number of IP packets sent to the LAN Number of IP packets incorrectly received from the LAN Number of IP packets received from the LAN for an incorrect service Number of packets from the LAN that actually should have been fragmented prior to transmission due to their size but which could not be fragmented Number of IP packets received from the cable network Number of IP packets sent to the cable network Number of IP packets incorrectly received from the cable network Number of IP packets received from the cable network for an incor rect service Number of packets from the cable network that actually should have been fragmented prior to transmission due to their size but which could not be fragmented Number of packets discarded by the cable network due to timeout Deletes IP statistics Status TCP IP statistics ICM P statistics These statistics include the following values ICM P LAN rx ICM P LAN tx I
103. network mask Use the M asquerade option to inform the cable modem which of the two addresses to use when transferring the packets Off No masquerading Use this entry to apply the cable IP address that was assigned during the registration at the headend by the network operator If the cable modem is used as an IP router without masquerading make sure that IP RIP is enabled When using itas an IP router with masquerading IP RIP should be disabled How does IP masquerading work M asquerading makes use of a characteristic of TCP IP data transmission which is to use port numbers for destination and source as well as the source and destination addresses W hen the router receives a data packet for transfer it now notes the IP address and the Sender s port in an internal table It then gives the packet its unique cable IP address and a random new port number It also enters this new port on the table and forwards the packet with the new information The response to this new packet is now sent to the cable IP address of the cable modem with the new sender port number The entry in the internal table allows the router to assign this response to the original sender again You can view these tables in detail the router statistics see also Status Simple and inverse masquerading This masking operates in both directions The local network behind the cable IP address of the router is masked if a computer from the LAN of the user
104. nk Cable Description of the menu options Description of the menu options The menu tree for ELSA MicroLink Cable configuration is divided up into status information setup parameters firmware information and other In order to help you familiarize yourself with the system you will first be given an overview of the menu structure In the complete list of all menu options you will find a detailed description of all displays menus and actions along with their associated parameters default settings and input options You can access the menus when configuring via telnet or terminal programs and via SNMP also see Configuration M odes When configuring with ELSA LAN config you are provided with an integrated help system that gives you brief descriptions of the individual parameters All channel related statistics and menus in this documentation refer to two channels only even if more than two channels are available to the specific devices Interface related information is also provided for a single interface only The information is equally applicable to the additional channels and interfaces Symbols Menu Indicates a further submenu Info Indicates a value that cannot be modified Value Indicates a value that can be modified Table Indicates a table whose entries can be modified Info table Indicates a table whose entries cannot be modified Action Performs an action ELSA MicroLink Cable
105. nnel for communication with the provider has been found the headend gives a set of instructions to the cable modem that is important to the operation in the cable network This process is called registration It includes The confirmation of the found channel or the transfer to another channel The allocation of an IP address that is valid in the cable network along with a suitable netmask Information on the provider s server addresses The current time After the registration is completed successfully the Reg d LED on the ELSA M icroLink Cable lights up and the cable modem is ready to access the Internet ELSA MicroLink Cable Technical basics Q Network transmission medium interfaces Q Packets Cells Q Host Router Point to point connection Netw ork technology This section will give you a brief introduction to the basics of network technology These descriptions do not cover all possible techniques processes and terms associated with network technology They only cover the topic to the degree necessary to provide an understanding of the product information The netw ork and its components W henever several computers communicate with one another this connection is called a network For computers to be able to communicate they need a physical medium through which the information can be transmitted This can be a cable or radio link for example that is connected to the computers using special i
106. nsmitted using IP masquerading Naturally only those which also communicate using ports Protocols working without port numbers or using ports above IP in the OSI model cannot be masked without special treatment The current version of router implements masquerading for the following protocols TCP and all TCP based protocols such as FTP HTTP etc UDP ICM P DNS forwarding Names rather than IP addresses are generally used to access a server over the Internet Who knows which address is behind w ww domain com The DNS server of course DNS stands for Domain Name Service refers to the assignment of domain names such as domain com to the corresponding IP addresses This information must be constantly updated and be accessible all over the world at any time DNS servers holding long tables containing IP addresses and domain names exist for this purpose If a computer calls up a home page from the intranet it first sends out a DNS request What is the IP address associated with www domain com This request is dealt with as follows if the cable modem is registered as the DNS server forthe workstation computers ELSA MicroLink Cable Operating modes and functions Initially the router checks whether a DNS server has been entered in its own settings in configuration tool ELSA LANconfig in the TCP IP configuration section on the Addresses tab or in Setup TCP IP Module menu lf it finds it there it will then retrieve th
107. nt downstream frequency found Synchronization state 9 QAM FEC and synchronization Upstream descriptor found 9 ee upstream configuration found in the down Upstream power 9 Current transmission power in dBm Ranging state 9 Status of the ranging process DHCP state 9 Status of the DHCP negotiation ToD state 9 Display of the Time of day negotiation Configuration file state 9 Status of the configuration file download Registration state 9 Status of the registration with the headend Service ID 9 Service ID during and after registration ELSA MicroLink Cable Description of the menu options Cable statistics Class ID Upstream channel ID Downstream channel ID Status DHCP client statistics DHCP client statistics Ho Class ID after registration Number of the upstream channel Number of the downstream channel State Lease time Your IP address Your IP netmask Gatew ay IP address Server IP address Security server Time offset Time server Table time server Table router Table name server Table domain name server Table log server Configuration file Setup Q jl Q jl jl Q jl jl Status of the DHCP client on or off Validity for the values assigned IP address assigned by the headend IP netmask assigned by the headend IP address assigned by the headend for BOOTP Server IP address assigned by the headend Security server IP addres
108. ntered This and all high order bits within the network mask are set Thus for example the address 127 128 128 64 yields the IP network mask 255 255 255 192 Cl Addr The network mask is formed from the IP address class and a part attached using the address procedure Thus the above mentioned address and the network mask 255 255 0 0 yield the IP network mask 255 128 0 0 This option allows you to display the entries in the current dynamic IP routing table ELSA MicroLink Cable tig Description of the menu options Cable RIP LAN RIP Service table An IP RIP routing table might for example have the following appearance IP address IP netmask Time Distance Router 223 245 254 0 255 255 255 0 1192 38 9 100 223 245 257 0 255 255 255 0 fi 192 38 9 200 Select whether RIP packets should be sent into the LAN or cable network here Setup IP router module M asquerading This menu allows you to enter settings for the masquerading function The menu has the following layout Masquerading Settings for IP masquerading Operating M asquerading function on or off 4 TCP aging second s seconds after which masquerading becomes invali UDP aging second s seconds after which UDP masquerading becomes invali ICM P aging second s 5 seconds after which an ICM P masquerading becomes invali Service table Static masquerading table Table masquerading Dynamic masquerading ta
109. nterfaces e g network adapters The term network cable or simply cable in the following text also refers to any other physical medium that can take on the function of the cable such as wireless links The individual bits of electronic information that are sent from one computer to another through a medium are called packets or cells depending on the process For most of the following explanations the difference between packets and cells is irrelevant Therefore we will use the term packet or data packet in a general sense and only detail the special characteristics of cells as necessary The computer and other terminal devices e g the printer in a network that generate or process information are called hosts Ideally a host is not responsible for the task of forwarding information A host normally has exactly one interface to the network The transport of packets between two hosts occurs indirectly through exchanges that pass packets on to the target computer These exchanges are called routers A router has at least two interfaces so that it can receive the data from a sender and pass them onto a recipient Apart from the exchange function the router also has the properties of a host so that it can also be the recipient of data packets for configuration purposes for example Connection modes The connection of exactly two hosts via a medium is called a point to point connection In this case a host sends packets that can only
110. nu options f the device no longer responds and it is therefore impossible to log in the firmware automatically loads the previous firmware version and reboots the device with it manual The third option allows you to set a period Timeout firmsafe beforehand for testing the new firmware The device will start with the new firmware and wait for the preset period until the loaded firmware is manually activated and therefore becomes permanently effective Other The Other menu allows you to manage the following functions Other Various functions Boot system Boots the device Factory default Resets to factory settings system Upload system Loads new firmware Boot system This option allows you to reboot the device O Before executing the command all open connections will be released or closed The device must log back on with network operator after rebooting Factory default This option resets all the settings that have been entered The device is reset to the System factory settings For security reasons the system prompts you to enter the configuration protection password in order to ensure that you have not mistakenly selected this command instead of the Boot system command If no password has been assigned you must press Enter a second time Upload system This option starts a firmware upload refer to chapter How to load new software The flash ROM technology permits flexible and service friend
111. o involves specifying in the M IB the variables which should have read only or read write status Commercially available SNM P managers indicate read only and read write status using color coding Access protection in SNMP V 1 Access to SNMP objects is controlled using so called communities A community is basically a password used to govern access to particular classes of information The router permits read only access to all parameters and tables through the public community Bear in mind that this community cannot execute any write accesses You must use the device s password if you wish to write data using SNM P Write access using SNM P will not be granted as a matter of principle if the device s password is not entered If the trapping mechanism is enabled and a failed access attempt is detected an Authentication Failed trap is triggered and sent to the manager s in the SNMP trap table ELSA icroLink Cable Configuration modes Bear mind that the access protection given by the community mechanism in the SN M V lisonly very limited since the data the M IB IDs and the communities are not encrypted in the UDP data blocks of requests and responses as they are transmitted Deleting rows in tables using SNMP SNMP itself has no mechanisms intended for deleting You therefore have to use a trick to delete entries from tables If you need to delete a row you have to change the index entry value i e the valu
112. on to the host of the employee Sam Smith Now we Shall take a look at the example using proper IP addresses instead of symbolic names The network of Example Inc has the numerical space 192 168 100 0 to 192 168 100 255 at its disposal with the 0 for the network address and the 255 for the sender address ELSA MicroLink Cable M edia access control LAN and IP network Technical basics All the router has to remember is that every address beginning with 192 168 100 is located within the network of Example Inc Now imagine a router that is connected to the network of Example Inc through an interface If it receives a packet with destination address 192 168 100 4 and netmask 255 255 255 0 it will compare this with every network address it knows In doing so it carries out a logical AND with the netmask and compares the results with the network address 192 168 100 4 AND 255 255 255 0 is 192 168 100 0 This is the network address of the Example Inc network The router recognizes that the recipient is located within Example Inc and passes the packet on to the appropriate interface for Example Inc Within Example Inc the packet is then passed on to the appropriate subnet The same procedure is used for the transfer of IP packets within a network CD host in the subnet of the development department wants to send a data packet to Mr Smith the sender attaches the destination address Host Smith M ark
113. over DHCP rx request DHCP rx decline DHCP rx inform DHCP rx release DHCP tx offer DHCP tx ack DHCP tx nak Number of DHCP packets received from the LAN Number of DHCP packets sent to the LAN Number of DHCP packets received from the cable network Number of DHCP packets discarded Number of discover messages received Number of request messages received Number of decline messages received Number of inform messages received Number of release messages received Number of offer messages sent Number of DHCP packets acknowledged Number of DHCP packets not acknowledged DCHP server err DHCP assigned DHCP M AC conflicts Table DHCP Delete values ELSA MicroLink Cable Number of DHCP packets received that were not intended for this server Number of addresses currently assigned Number of assignments rejected because IP addresses were in use Table containing assignments of IP addresses to M AC addresses Deletes DHCP statistics Table DHCP Description of the menu options There are entries with DHCP information in the DHCP table It contains 16 entries or multiples of 16 The table adapts dynamically to the given requirements and grows or shrinks accordingly It has the following layout IP address Node ID Timeout Hostname Type IP address assigned via Associated Duration of assignment Computer Assign address validity in minutes name ment type Status IP router statistics This menu groups
114. quest The DEFAULT value of 500 minutes equals approximately 8 hours In the DCHP module the Table DCHP option allows you to verify or look up the assignment of IP addresses to the relevant computers This table has the following layout IP address Node ID Timeout Hostname Type 101110 00a0570308e1 500 ELSA new IP address IP address assigned Node IP The computer s Ethernet address Timeout Time remaining until the assignment becomes invalid Hostname The computer s name in plain text if it was transmitted in the request Type This field contains additional information on the assignment The field specifies how the address was assigned This field can assume the following values new The computer has made its initial request The DHCP server verifies the uniqueness of the address that is to be assigned to the computer unkn While verifying uniqueness it was determined that the address has already been assigned to another computer Unfortunately the DHCP server has no means of obtaining additional information on this computer Stat A computer has informed the DHCP server that it has a fixed IP address This address can no longer be used dyn The DHCP server assigned an address to the computer Setup Config module This menu allows you to enter settings for router configuration options The menu has the follow ing layout Config module Configuration module settings Password re
115. quired Password required on off if there is no password Switch Off mode my Configuration of the On Standby switch Standby 9 Standby status Config aging minute s Time limit for remote configuration connections ELSA MicroLink Cable l Description of the menu options Config module Configuration module settings Login errors Number for failed log in attempts before the log in block is activated Lock minutes Duration of block and period until old log in errors are for gotten Language Configuration language Password This specifies whether a new password should be requested every time a configuration required is begun On or the password request should be suppressed Off The default setting for this option is Off Config aging f data transmission halts during a remote configuration session e g because the user is minute s no longer entering data the device automatically releases the connection at the end of the time period specified here Possible settings are from 1 to 99 minutes The default setting is 15 minutes Login errors This entry specifies the number of failed attempts allowed before the log in block is activated An empty password simply pressing lt ENTER gt at the password prompt is not considered an attempt and therefore does not activate the block The default value is 5 A lower value may cause the log in block to be activated with only AN one access on an older ELSA LANconfig In t
116. r of TFTP packets received from the cable network ELSA MicroLink Cable Description of the menu options TFTP cable rx read request TFTP cable rx w rite request TFTP cable rx data TFTP cable rx ack TFTP cable rx option ack TFTP cable rx errors TFTP cable rx bad packets TFTP cable tx TFTP cable tx data TFTP cable tx ack TFTP cable tx option ack TFTP cable tx errors TFTP cable tx repeats TFTP cable connections Delete values Number of TFTP read requests received from the cable network Number of TFTP write requests received from the cable network Number of TFTP data packets received from the cable network Number of TFTP acknowledges received from the cable network Number of TFTP option acknowledges received from the cable net Work Number of TFTP error packets received from the cable network Number of unknown TFTP packets received from the cable network Number of TFTP packets sent to the cable network Number of TFTP data packets sent to the cable network Number of TFTP acknowledges sent to the cable network N umber of TFTP option acknowledges sent to the cable network Number of TFTP error packets sent to the cable network Number of TFTP packets repeatedly sent to the cable network Number of TFTP connections established to the cable network Deletes TFTP statistics Status TCP IP statistic s DHCP statistics These statistics include the following values DHCP LAN rx DHCP LAN tx DHCP cable rx DHCP discard DHCP rx disc
117. race outputs in the reference section of this guide New firmware with FirmSafe The software for the devices of ELSA is constantly being updated We have fitted the units with a flash ROM which makes child s play of updating the operating software so that you can enjoy the benefits of new features and functions No need to change the EPROM no need to open up the case simply load the new release and you re away This is how FirmSafe works FirmSafe makes the installation of the new software safe The current firmware is not simply overwritten but saved additionally in the device as a second firmware Only one of the firmware versions stored in the device can be active at any one time When new firmware is loaded the inactive firmware is overwritten You can decide which firmware version you want to activate after the upload mmediate The first option is to load the new firmware and activate it immediately The following situations can result The new firmware is successfully loaded and then operates as desired Everything is then in order ELSA MicroLink Cable Configuration modes The device no longer responds after loading the new firmware If an error occurs during the upload the router automatically reactivates the previous firmware version and reboots the device Login To avoid problems with faulty uploads there is the second option with which the firmware is uploaded and also immediately booted The difference
118. radio frequency energy lt may interfere with radio communications if not installed and used in accordance with the instructions However there is no guarantee that interference will not occur in a particular installation If this equipment does cause interference to radio or television reception this can be determined by turning this equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient or relocate the receiving antenna Increase the distance between this equipment and the receiver Connect the equipment to an outlet on a circuit other than that to which the receiver is connected Consult your dealer or an experienced radio TV technician Caution To comply with the limits for an FCC Class B computing device always use a shielded signal cable The Federal Communications Commission warns the user that changes or modifications to the unit not expressly approved by the party responsible for compliance could void the user s authority to operate the equipment ELSA MicroLink Cable mn Introducing the ELSA M icroLink Cable ELSA MicroLink Cable Installation and configuration 9 Installation and configuration The aim of this chapter is to get you online as quickly as possible First please check that the contents of the package are complete ELSA M icroLink Cable Power supply Twisted pair LAN connector cable WAN connector cable coaxial or corresponding a
119. rk Number of TCP packets repeatedly sent to the cable network N TUM of TCP packets incorrectly received from the cable net wor Number of TCP packets received from the cable network for an incorrect port Current number of TCP connections from the WAN Deletes TCP statistics Status TCP IP statistics TFTP statistics These statistics include the following values TFTP LAN rx TFTP LAN rx read request TFTP LAN rx write request TFTP LAN rx data TFTP LAN TFTP LAN rx option ack TFTP LAN rx errors TFTP LAN rx bad packets TFTP LAN tx TFTP LAN tx data TFTP LAN tx ack TFTP LAN tx option ack TFTP LAN tx errors TFTP LAN tx repeats TFTP LAN connections TFTP cable rx Number of TFTP packets received from the LAN Number of TFTP read requests received from the LAN Number of TFTP write requests received from the LAN Number of TFTP data packets received from the LAN Number of TFTP acknowledges received from the LAN N umber of TFTP option acknowledges received from the LAN Number of TFTP error packets received from the LAN Number of unknown TFTP packets received from the LAN Number of TFTP packets sent to the LAN Number of TFTP data packets sent to the LAN Number of TFTP acknowledges sent to the LAN N umber of TFTP option acknowledges sent to the LAN Number of TFTP error packets sent to the LAN N umber of TFTP packets repeatedly sent to the LAN Number of TFTP connections established to the LAN Numbe
120. route with the IP address 255 255 255 255 with a network mask of 0 0 0 0 is the default route Any data packets which cannot be routed by other routing entries are transmitted via this route Router Name The router name indicates what should be done with the data packets that correspond to the IP address and the network mask Routes with the router name 0 0 0 0 describe Exclusion routes Data packets for this zero route are rejected and are not routed any further This is how routes which are forbidden on the Internet private address spaces e g 10 0 0 0 for example are excluded from transmission If a router name consists of an IP address this means we are dealing with a locally accessible router responsible for the transmission of the appropriate data packets By default you will find the entry CABLE in the cable modem as a router name at the default route All IP data packets transferred via this route are forwarded to the cable interface Distance Number of routers between your own and the destination router Examples with explanatory notes IP address IP netmask Routername Dist This is what happens 192 168 130 0 255 255 255 0 192 168 140 123 0 All data packets with destination IP addresses 192 168 130 x are transmitted to the locally accessi ble router with the IP address 192 168 140 123 ELSA icroLink Cable Operating modes and functions IP address IP netmask Routername Dist Thisis
121. rs for reception in the MAC chip Number of receive FIFO overruns Number of unanswered bandwidth request packets Number of packets not received due to a lack of buffers Number of control packets not received due to a lack of buffers Number of control packets incorrectly received Number of M CNS header incorrectly received Number of data packets sent Number of data packets received Number of control packets sent Number of control packets received Cable statistics Description of the menu options Running status displays Cable rx M CN S header valid Cable FEC lock losts not recovered Cable FEC lock losts reco vered Cable TRC lock losts not recovered Cable TRC lock losts reco vered Delete values ye Status LAN statistics Similarly to the previous menu option this option allows you to display the statistics relating to the LAN connection The Status LAN statistics menu has the following layout LAN statistics Number of MCNS headers correctly received Number of cable FEC lock losses not synchronized Number of cable FEC lock losses resynchronized Number of cable TRC lock losses not synchronized Number of cable TRC lock losses resynchronized Deletes Cable statistics Running status displays LAN rx packets LAN tx packets LAN rx errors LAN tx errors LAN stack errors LAN NIC errors LAN heap packets LAN queue packets LAN queue errors LAN collisions LAN rx bytes LAN
122. s displays the current WAN statistics every 3 seconds time 24 12 1998 18 00 00 Languages currently supported English language english German language deutsch ELSA icroLink Cable Configuration modes Text entries with spaces are only accepted if they are placed in quotation marks e g set se snmp admin The Administrator Text entries individual and table values can be deleted as follow s set se snmp admin ELSA MicroLink Cable O Configuration modes What s happening on the line Trace Outputs Trace outputs may be used to monitor the internal processes in the cable modem during or after configuration The trace outputs are slightly delayed behind the actual event but are always in the correct sequence This will not usually hamper interpretation of the displays but should be taken into consideration if making precise analyses How to starta trace The command to call up a trace follows this syntax trace code parameters The trace command the code the parameters and the combination commands are all separated from each other by spaces And what is lurking behind the code and parameters This code combination with the trace causes the follow ing Displays a help text t switches on a trace output Switches off a trace output Switches between different trace outputs toggle no code Displays the current status of the trace This parameter brings up the
123. s assigned by the headend Offset in seconds relative to GMT Currently used time server Table of time servers Table of routers Table of name servers Table of domain name servers Table of log servers Current configuration file This menu allows you to query and modify all the system parameters that are necessary to the functioning of the devices Setup System configuration Name Entering the device name Cable module Cable network settings LAN module LAN settings Bridge module TCP IP module ELSA MicroLink Cable Remote bridge settings TCP IP module settings Name Description of the menu options Setup System configuration IP router module m IP router module settings SNM P module a Settings for configuration via SNM DHCP server module DHCP server settings Config module Configuration module settings Here you can enter the device name maximum 16 characters The set of characters available includes uppercase and lowercase letters as well as some special characters You can display the full range of available characters during a configuration session by entering the following command set setup name In the default configuration no name is entered Setup Cable module This menu groups together all the settings necessary for starting up the interface to the cable network and for the connection to the headend These settings should only b
124. s not absolutely essential that you configure the correct IP addresses manually the DHCP server can perform this task for you automatically When using the DHCP server you can have the IP addresses for all computers on the network assigned automatically see also chapter Automatic Address Administration with DHCP ELSA MicroLink Cable Configuration modes Starting inband configuration using ELSA LANconfig After the installation double click on autorun exe is complete call up the ELSA LAN config configuration tool for example by clicking on Start gt Programs gt ELSAlan ELSA LANconfig in the Windows task bar ELSA LANconfig searches the local area network for ELSA M icroLink Cable devices ust click on the Find button or call up the command with Device gt Find to initiate a search for new device manually ELSA LANconfig will then prompt you for a location to search You will only need to specify the local area network if using the inband solution and then you re off Once ELSA LAN config has finished its search it displays a list of all the devices it has found together with their names and a description if available the IP address and its Status HELSA LANconfig LE Oy Device Edit View Tools Help lala ERS 193 103 233 254 Ok Glasgow MicroLink Cable 0 92 28 07 83 SN 8823 000 260 Double clicking the entry for the highlighted device and then clicking
125. sk LAN IP address r IP address for the device in the local network LAN ELSA MicroLink Cable LEVA Description of the menu options Operating Cable IP address IP netmask Cable IP netmask LAN IP address LAN IP netmask A TCP IP module TCP IP module settings LAN IP mask LAN s matching IP network mask Access list Restricts access to internal functions via TCP IP Table A RP ARP table for mapping an IP address onto a MAC address ARP aging min Dwell time for entries in the ARP table TCP aging min Time limit for configuration connections that are inactive M ax number of simultaneous configuration connections to the TCP max conn 5 ELSA M icroLink Cable The TCP IP module of the router may be activated or deactivated here In the default configuration the TCP IP module is activated Configuration via TCP IP using Telnet and the IP router can only be used if the TCP IP module is activated The IP address for the device as transmitted by the headend during the registration is displayed here The default address on delivery is 0 0 0 0 This IP address is used by the cable modem for the connection to the provider s cable network operator netw ork The network mask belonging to the IP address must be entered here The default setting is 255 255 255 0 class C network A network mask of 255 255 255 255 means that there is only one computer in this network the router itself
126. squerading This is a procedure whereby only one LAN router appears on the Internet with an IP address This IP address is allocated to the router either permanently by the NIC or temporarily by an Internet provider All the other computers on the network then conceal themselves behind this one IP address Aside from the welcome savings IP masquerading has the added benefit of guarding very effectively against attacks on the local network from the Internet The IP masquerading function is connected to the operating mode of the cable modem as a router Whenever routers are mentioned in the following paragraphs this is a reference to the cable modem in the operating mode of an IP router O Two addresses for the router M asquerading pits two opposing requirements of the router against one another On the one hand it has to have a valid IP address in the local netw ork of the user so that it can be reached from the LAN On the other hand it has to have a valid address in the cable network Since these two addresses may not in principle be located on the same logical network there is only one solution two IP addresses are required ELSA MicroLink Cable Lo Operating modes and functions Cable TV net LAN of the user Work f Cable IP address LAN IP address d E mons o 72 ELSA M icroLink Hub Cable The cable modem is therefore assigned a cable IP address and a LAN IP address each With its own appropriate
127. ssign a different free LAN IP address to the cable modem The access to internal functions of the router may be controlled by an access list in TCP IP applications The configuration data of the device are protected by a password how ever this is always transferred in plain text making it possible in principle to detect it and for any computer to read the configuration or to delete it In order to prevent this from happening the access list can be used to determine which computers or which networks can access the configuration For reasons of consistency the access control is based on all internal functions of the router The term internal functions refers to the following Telnet server The configuration interface based on the Telnet protocol TFTP server The configuration interface based on the TFT protocol SNM P the configuration interface based on the SNMP Each of the maximum of 16 entries in the access list has the following structure IP address IP netmask IP address of the authorized user or user IP network mask of the user circle circle Once an IP workstation with its IP address and the network mask 255 255 255 255 is entered into the list the internal functions of the router can only be accessed from this computer Any requests from devices with different IP addresses are ignored If a complete network has access enabled to a ELSA M icroLink Cable this can be done as follows for a class C network IP ad
128. technical specifications ELSA icroLink Cable if the damage occurred due to incorrect handling especially to non observance of the system description and the operating instructions if the device was opened repaired or modified by persons not authorized by ELSA if the device shows any kind of mechanical damage if in the case of an ELSA M onitor damage to the cathode ray tube CRT has been caused especially by mechanical load e g from shock to the pitch mask assembly or damage to the glass tube by strong magnetic fields near the CRT colored dots on the screen or through the permanent display of an unchanging image phosphor burnt if and in as far as the luminance of the TFT panel backlighting gradually decreases with time or if the warranty claim has not been reported in accordance with 3a or 3b Operating mistakes If it becomes apparent that the reported malfunction of the device has been caused by unsuitable software hardware installation or operation ELSA reserves the right to charge the purchaser for the resulting testing costs Additional regulations The above conditions define the complete scope of ELSA s legal liability The warranty gives no entitlement to additional claims such as any refund in full or in part Compensation claims regardless of the legal basis are excluded This does not apply if e g injury to persons or damage to private property are specifically covered by the product liability law
129. ternetwork The largest union of many small public IP networks is the Internet A network covering a limited area with hosts on the same hierarchical level and using the same medium shared medium is called a local network Local Area Network LAN IP addressing In IP networks the communication between computers takes place in a packet oriented fashion This means that data or messages are packed together in packets of variable length and are as such sent from the source computer to the target computer Apart from ELSA MicroLink Cable IP address O Network address Netmask Technical basics the actual information to be transmitted useful data the data packet also contains address and control information IP addresses are used in IP networks for communications between various devices In this case every host has its own unique address by which it can be identified unambiguously What does an IP address look like It consists of four bytes separated by dots making a total of 32 bits Each of the four bytes can take on values from 0 to 255 e g 192 168 130 124 To be precise the IP address refers to the interface and not the host itself A terminal device with more than one interface such as a router has to have an IP address at its disposal for every single interface This is why ISDN routers from ELSA for example have an IP address for communication with the hosts in their own network as well as a second IP address
130. the cable TV network has a very high bandwidth at its disposal thus the term broadband cable network The full bandwidth is divided up into a variety of channels that are reserved for the transmission of different kinds of information You know this from television where you also find different ELSA MicroLink Cable Synchronizing Finding a channel in the broadband network A Registration Exchange of administration information between head end and cable modem Technical basics programs on their respective channels Specific channels are also set up for the transmission of Internet content After being switched on the cable modem searches the entire frequency band for a channel used by the provider to send information from the Internet Because the bandwidth is so great the first time the log on procedure might take a while As soon as the corresponding channel is found the Sync LED on the ELSA M icroLink Cable flashes The next time the cable modem is switched on it will first look for the channel it found the previous time and thus find the wanted information at a substantially faster rate However if the cable modem is used on another connection it may have to search the entire frequency band again To speed up the search providers can preset the ELSA M icroLink Cable to search the particular frequency bands that they normally use Do not change these settings yourself without consulting your provider W hen a cha
131. the current menu The menu has the follow ing layout Status Running status displays Operating time Current time Cable statistics LAN statistics Bridge statistics TCP IP statistics IP router statistics Config statistics Queue statistics M CNS statistics Init status DHCP client status Info connection Layer connection Channel statistics Time statistics LCR statistics Output internal status messages Delete values Period of time the device has operated since it was last switched on Current time in device Display of statistics related to the cable network Displays LAN statistics Bridge area statistics Statistics from the TCP IP area Statistics from the IP router Remote configuration statistics Statistics relating to the packets in the queues of the individual modules Statistics relating to M CNS packets and M CNS timeouts Status of initialization process Status of the DHCP client and the negotiated values Information on the last connection for each interface Information on the B channel protocol used for each interface Information of the status of the individual channels Time module information Least cost router information Query of the internal system status messages Deletes all values except tables with substatistics ELSA MicroLink Cable Status Operating time Description of the
132. the various tabs for special entries such as for the IP address or the standard gateway If you would like all of the values to be assigned by the DHCP server simply delete the corresponding entries Priority for a workstation overwriting an assignment If a computer uses parameters other than those assigned to it e g a different default gateway these parameters must be set directly on the workstation computer The computer then ignores the corresponding parameters assigned to it by the DHCP server Under W indows this can for example be performed via the properties of the network environment Click Start gt Settings gt Control Panel gt Network Select the TCP IP entry for your network adapter and open Properties You can now enter the desired values by selecting the various tabs The assignment of IP addresses to the various computers can be checked using the Setup DHCP Table DHCP item in the router s DHCP module This table contains the assigned IP address the MAC address the validity the name of the computer if available and the type of address assignment The Type field specifies how the address was assigned This field can assume the following values new ELSA MicroLink Cable Operating modes and functions The computer has made its initial request The DHCP server verifies the uniqueness of the address that is to be assigned to the computer unknown While verifying uniqueness it was determined t
133. then decides whether it is the recipient of the packet or not If the packet is addressed to the corresponding host it will then accept it If not the host will ignore reject it This is a point to multipoint connection since we are not dealing with an unambiguous connection ELSA icroLink Cable Technical basics Protocol TCP IP IP network Internetwork Internet Local network LAN Packet oriented transfer Host Host Sender Data packet with recipient information 11 n Eo DX B a283 X i xm 8 MITES Host Recipient Kinds of networks An important prerequisite for communications between computers is a common language among the hosts In the world of network technology this language is called network protocol or simply protocol The most broadly distributed network protocol is the TCP IP Transmission Control Protocol Internet Protocol It is used mainly in the Internet but nowadays more and more company networks use Examples of other network protocols are IPX or Apple Talk Because of its wide use this chapter deals mainly with the TCP IP All hosts wanting to communicate using the TCP IP protocol have to be plugged into the same network and have to have the TCP IP protocol also known as TCP IP stack installed Such a network is referred to as an IP network The connection of multiple networks based on the IP protocol is referred to as an in
134. tination addresses Dest address Destination address filtering Filter type Positive or negative filter Filter table Processing of address filter table The filter type to be used for the destination address list may be specified here The settings pos are possible so only data packets whose destination address is included in the destination address filter table will be transferred The setting neg default value transfers all frames whose destination addresses are not included in the destination address filter table The destination addresses can be administered in this table Entries simply comprise the MAC address field Dest 0000c051d266 Setup B ridge module LAN configuration Source addresses The settings for source addresses are made in the same way as the settings for the destination addresses Setup B ridge module cable c onfiguration This option allows you to select the settings for cable data packets The settings in this menu are exactly the same as the settings in the LAN configuration menu except that they serve to filter the data packets received from the cable network Setup TCP IP module This menu allows you to enter settings for the TCP IP module The menu has the following layout TCP IP module TCP IP module settings Operating Activates or deactivates the TCP IP module Cable IP address IP address of the device in the cable network Cable IP netmask Cable network s matching IP network ma
135. tion IP addresses are discarded and are not answered by proxy ARP This is done by entering 0 0 0 0 for the name of the responsible router The IP routing table is generally sorted as shown below The longest network mask is placed on top For network masks of equal length the one with the smallest IP address is placed on top Address ranges that are prohibited in the Internet are excluded from transmission by preset entries in the IP routing table the router name 0 0 0 0 means that packets to these addresses are not transmitted The IP routing table below is provided by way of example and also shows the default settings IP address IP netmask Router name Distance 192 168 0 0 255 255 0 0 0 0 0 0 0 172 16 0 0 255 240 0 0 0 0 0 0 0 10 0 0 0 255 0 0 0 0 0 0 0 0 255 255 255 255 0 0 0 0 Cable TV network 0 How ever if these addresses are required for Intranet use for example it is possible to delete the predefined entries at any time If the routing table contains no entries with the router name 0 0 0 0 the router processes all IP addresses with valid routes The last line is an entry for the default route The IP address 255 255 255 255 means the same as 0 0 0 0 for technical reasons 0 0 0 0 cannot be entered in the first column Because it contains the IP network mask 0 0 0 0 this line is always appropriate after the rest of the table has been searched The router with the name Cable stands for the cable network The router
136. to be transmitted Setup Bridge Module LAN config Dest address Filter type pos or the addresses to be excluded Filter type neg You then enter the M AC addresses to be filtered into the table itself This method of filtering by entering the exact M AC address naturally demands a certain AN degree of maintenance effort Should the addresses change when a network adapter is changed for example the new addresses must be entered to ensure that the bridge continues to function Automatic address administration with DHCP In order to operate smoothly in a TCP IP network all the devices in a local network must have unique IP addresses In addition to the IP addresses the devices in the LAN also need the addresses of DNSs as well as that of a default gateway through which the data packets are to be routed from addresses that are not available locally In a smaller network it is still conceivable that these addresses could be entered manually in all the computers in the network In a larger network with many workstation computers how ever this would simply be too enormous of a task In such situations the DHCP Dynamic Host Configuration Protocol is the ideal solution Using this protocol a DHCP server in a TCP IP based LAN can dynamically assign the necessary addresses to the individual stations ELSA MicroLink Cable O Operating modes and functions The cable modem really belongs to two LANs On one side it is
137. to the first option is that the router then waits five minutes for a successful login to the device via outband or inband via telnet Only if this login attempt is successful does the new firmware remain active permanently fthe device no longer responds and it is therefore impossible to log in the router automatically loads the previous firmware version and reboots the device with it anual With the third option you can define a time period during which you want to test the new firmware yourself The router will start with the new firmware and wait for the preset period until the loaded firmware is manually activated and therefore becomes permanently effective How to load new softw are There are various ways of carrying out a firmware upload which is the term given to the installation of software all of which produce the same result Configurations tool ELSA LANconfig recommended Terminal programs TFTP All settings will remain unchanged by a firmware upload All the same you should save the configuration first for safety s sake with Edit Save Configuration to File if using ELSA LANconfig for example If the newly installed release contains parameters which are not present in the device s current firmware the router will add the missing values using the default settings ELSA LANconfig W hen using the ELSA LANconfig configuration tool highlight the desired device in the selection list and click Edit gt
138. to your local network using the twisted pair cable Please check the position of the node hub switch Node is the correct position when connecting the unit to a network Switch to Hub when connecting the unit directly to a workstation EZ The wire to the world Connect the ELSA M icroLink Cable to the TV cable network using the coaxial cable or the adapter and a normal antenna cable Data is transmitted through the cable TV network in accordance with the M CNS M ultimedia Cable Network System DOCSIS standard The connection to the cable TV network must provide a certain signal level This value will be checked by your cable network operator and adjusted as required And we re off Switch the device on at the back The Power LED on the front panel lights up after a short self test The LAN Link LED indicates that the unit is correctly connected to the LAN and that the Node Hub switch is correctly set If this LED is not lit change the position of the Node Hub switch If the LED still does not light up there may be a problem with the network adapter or the cabling Softw are installation The ELSA LANconfig configuration software for Windows 95 Windows 98 or Windows NT 4 0 may be used to configure the unit as required or to set it up for other applications Alternatively you can perform the configuration via telnet from any other TCP IP capable computer e g Linux Solaris Install the TCP IP network protocol followed by the EL
139. together the statistics from the IP router module IP router statistics Statistics from the IP router area IPr LAN rx 9 Number of data packets to be routed from the LAN IPr LAN tx 9 Number of data packets routed to the LAN IPr LAN local routings 9 yon of packets received from the LAN and routed to the IPr LAN netw ork errors 9 Number of LAN packets that were not routed IPr LAN routing errors 9 Number of LAN packets that must be sent to another router IPr LAN ttl errors 9 Number of LAN packets with an expired time to live value IPr LAN filters 9 Number of LAN packets filtered by the filter table IPr LAN discards 9 Number of LAN packets discarded IPr Cable rx Number of data packets to be routed from the cable net work IPr Cable tx 3 Number of data packets routed to the cable network IPr Cable netw ork errors 9 Number of cable network packets that were not routed IPr Cable ttl errors 9 Mao of cable network packets with an expired time to ue IPr Cable filters 3 Number of cable network packets filtered by the filter table IPr Cable discarded 9 Number of cable network packets discarded IPr Cable type errors 9 of packets from the cable network without an IP uter ID IPr ARP errors 9 Number of unsuccessful accesses to the ARP cache Protocol table Table of routed packets arranged by protocol RIP statistics Statistics from the IP RIP area Delete values a Deletes IP router statistics ELSA MicroLink Cable LE
140. ts received are placed in the reliable queue ELSA MicroLink Cable RIP type R1 mask Table IP RIP Description of the menu options Setup IP router module RIP configuration This option allows you to enter settings forthe management of IP RIP packets The menu has the following layout RIP configuration Settings for IP RIP operation RIP type RIP compatibility switch R1 mask M anagement of network masks Table IP RIP Dynamic IP routing table This option allows you to select the method to be used for handling the IP RIP packets The different settings have the following meaning Off IP RIP is not supported default RIP 1 RIP 1 and RIP 2 packets are received but only RIP 1 packets are sent R1 comp RIP 1 and RIP 2 packets are received RIP 2 packets are sent as an IP broadcast RIP 2 Same as RI comp except that all RIP packets are sent to the IP multicast address 224 0 0 9 If RIP 1 is set this option allows you to influence the management of network masks Therefore these settings are required only for subnetting under RIP 1 The different settings have the following meaning Class default The network mask used in the RIP packet is derived directly from the IP address class i e the following network masks are used for the network classes Class A 255 0 0 0 Class B 255 255 0 0 Class C 255 255 255 0 Address The network mask is derived from the first bit that is set in the IP address e
141. use these addresses In order for the computer to keep from constantly losing its addresses above all its IP address it applies for an extension ahead of time that it is generally sure to be granted The computer loses its address only if it is switched off when the period of validity expires ELSA icroLink Cable Operating modes and functions For each request a host can ask for a specific period of validity However a DHCP server can also assign the host a period of validity that differs from what it requested The DHCP module provides two settings for influencing the period of validity M aximum lease time in minutes Here you can enter the maximum period of validity that the DHCP server assigns a host If a host requests a validity in excess of 6000 minutes this will nevertheless be the maximum available validity The default setting is 6000 minutes approx 4 days Default lease time in minutes Here you can enter the period of validity that is assigned if the host makes no request The default setting is 500 minutes approx 8 hours Priority for the DHCP server Request assignment In the default configuration almost all the settings in the Window s network environment are selected in such a way that the necessary parameters are requested via DHCP Check the settings by clicking Start gt Settings gt Control Panel gt Network Select the TCP IP entry for your network adapter and open Properties Check
142. ute comes from the same router which notified this route but has a worse distance than the previous entry If a device notifies the degradation of its own static routing table in this way the cable modem will take this into account and include the poorer entry in its dynamic table The interaction of static and dynamic tables The router uses the static and dynamic tables to calculate the actual IP routing table it uses to determine the path for data packets In doing so it includes the routes from the dynamic table which it does not know itself or which indicate a shorter distance than its own static route with the routes from its own static table Local routing You know the following behavior of a workstation within a local network The computer searches for a router to assist with transmitting a data packet to an IP address which is not on its own LAN This router is usually notified to the operating system by its property of being the default router or gatew ay It is often only possible to enter one default router which is supposed to be able to reach all the IP addresses which are unknown to the Workstation computer if there are several routers in a network Occasionally however this default router cannot reach the destination network itself but does know another router which can find this destination How else can you assist the workstation computer By default the router sends the computer a response with the address of the router
143. ved for private networks 192 168 0 0 255 255 0 0 AIL IP addresses beginning with 192 168 and whose mask begins With 255 255 belong to the address range reserved for private use 224 0 0 0 224 0 0 0 All IP addresses beginning with a 224 which are associated with a net mask also beginning with 224 are within the reserved address range This range is reserved for broadcasting purposes and should not be used for private networks ELSA MicroLink Cable Routing Routing table Hierarchical IP addresses Technical basics There are two considerations when using these IP addresses The IP addresses used in a private network should not leave this network i e an Internet connection is only possible when using IP masquerading for example The packets for these IP addresses will not be routed in the Internet i e backbone routers will simply reject such IP packets Depending on the provider serious consequences may result if such IP packets are released on the Internet IP routing and hierarchical IP addressing Every IP packet contains the IP addresses of the source and of the recipient A router receives P packets at its interface interprets the destination address and passes the packets on to those interfaces that are nearest to the recipient Finding the appropriate path is called routing Every router manages a table routing table This table indicates the quickest interface connection to the host for every host in the
144. work using the received packets This is called an intelligent bridge ELSA icroLink Cable Technical basics ELSA MicroLink Cable Appendix Technical data Technical data ELSA MicroLink Cable Appendix LAN interface Cable TV interface Netw ork protocols Filter possibilities IP masquerading NAT PAT Management Display operation Power supply Ambient conditions Dimensions and design Ethernet IEEE 802 3 10Base T Twisted Pair 45 Node Hub switch M CNS DOCSIS ITU T J 112 physical layer as per Annex amp Annex B MAC as per Annex Socket Reception frequency band Reception channel width Receiver level Receiver modulation Receiver data rate S N ratio in receive direction Transmission frequency band Transmission channel width Transmission level Transmission modulation Transmission data rate S N ratio in transmit direction Bridge mode IP router Bridge mode IP router socket IEC169 2 connection via included adapter 88 860 M Hz 6 MHzor8 MHz 48 W 78 dBuV 64QAM 256QAM 30 34 M bps 64QAM 42 88 M bps 256QAM gt 21 dB 64 QAM gt 28 dB 256 QAM 5 42 MHz 5 65 M Hz optional 200 3200 kHz 85 122 QPSK 16QAM 0 32 5 12 M bps QPSK 0 64 10 24 M bps 16QAM 14 dB Burst QPSK gt 20 dB Burst 16QAM Bridging of all IEEE 802 3 based protocols IP TCP ICM P ARP RIP 1 RIP 2 PROXY ARP DRCP
145. xcepted from this warranty period are ELSA color monitors and ELSA videoconferencing systems with a warranty period of 3 years This period begins at the day of delivery from the ELSA dealer Warranty services do not result in an extension of the warranty period nor do they initiate a new warranty period The warranty period for installed replacement parts ends with the warranty period of the device as a whole Warranty procedure If defects appear during the warranty period the warranty claims must be made immediately at the latest within a period of 7 days In the case of any externally visible damage arising from transport e g damage to the housing the transport company representative and ELSA should be informed immediately On discovery of damage which is not externally visible the transport company and ELSA are to be immediately informed in writing at the latest within 7 days of delivery Transport to and from the location where the warranty claim is accepted and or the repaired device is exchanged is at the purchaser s own risk and cost Warranty claims are only valid if the original purchase receipt is returned with the device Suspension of the warranty All warranty claims will be deemed invalid a b if the device is damaged or destroyed as a result of acts of nature or by environmental influences moisture electric shock dust etc if the device was stored or operated under conditions not in compliance with the

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