TAHOE 681 / 682
Contents
1. USER MANUAL G shdsl modem with built in router TAHOE 681 682 FREEDOM OF COMMUNICATION TABLE OF CONTENTS 1 Introduction O 1 2 Interface Lie ue 3 3 Modem configuration using built in keyboard and LCD 5 4 Configuration using telnet or serial console 10 4 1 Telnet connection ak RAA A 10 4 2 SEMALEGNARIE Ao ORA 10 FDC MEGO 11 5 Technical data wad d Eo GO AAA GA 29 6 Declaration of Conformity 30 i 1 Tahoe 681 682 G shdsi Ethernet 10 100Base T modem User Manual http www tahoe group com Firmware version 1 2 6 2004 Tahoe All rights reserved Other trademarks of other companies are used only for explanation and to the owner s benefit without intent to infringe Tahoe assumes no responsibility for any errors or omissions that may appear in this document Tahoe makes no commitment to update the information contained here and may make changes at any time without notice oO EZM 1 Introduction Thank you for purchasing the Tahoe 681 682 modem We did our best to ensure highest reliability and performance of our products Devoting many years of research and development we are proud to provide a superior quality device unfolding new possibilities for the use of the copper lines Tahoe 680 series modems are G shdsl modems allowing data transmission with speeds up to 4864 kbps on 2 wire line or up to 9728 kbps on 4 wire line2. removes route to an IP address given route del net lt address gt netmask lt network mask gt removes route to a subnet specified route del default removes default route 4 3 24 snmp The snmp command is used to configure the SNMP Simple Network Management Protocol support It has following syntax snmp shows current settings Tahoe gt snmp SNMP on Read community public Write community private SNMP hostl lt any gt SNMP host2 lt disabled gt SNMP host3 lt disabled gt snmp on enables SNMP support snmp off disables SNMP support snmp rdcomm lt text gt sets the read community the password used to read the SNMP parameters snmp wrcomm lt text gt sets the write community password used to write the SNMP parameters snmp host1 lt address gt snmp host2 lt address gt snmp host3 lt address gt allows setting of up to 3 addresses from which the SNMP access will be permited Entering 0 0 0 0 allows access from any address while 255 255 255 255 disables an entry entering 255 255 255 255 in all three positions is equal to disabling the SNMP service 4 3 25 4 3 25 strictarp The strictarp command helps protecting the LAN against the unauthorized access After enabling strictarp mode by typing strictarp on and entering the static IP MAC assignments using arp add the modem would listen to incoming ARP requests aski
3. Thanks to powerful TCPAM 32 modulation throughputs are much higher than using HDSL technique and reach is nearly twice that of VDSL Adding low cost of deployment Tahoe modems become an interesting alternative even for fiber optic connections The modem exists in two versions Tahoe 681 up to 4864 kbps on 2 wire line o Tahoe 682 up to 9728 kbps on 4 wire line traffic is automatically divided between two lines fall back to 2 wire mode is done automatically in case o line failure The modem has a built in TCP IP router and an Ethernet 10 100Base T interface allowing connection directly to a LAN Router software supports IP ARP TCP UDP and ICMP protocols It is manageable using telnet SNMP serial console or built in LCD and keyboard Traffic statistics are available through WWW Modem status messages can be sent to a central server using syslog protocol One network interface may support more than one IP subnetwork thanks to interface aliases eth0 0 eth0 1 etc and VLAN interfaces eth0 1 ethO 2 etc Modem may also work as a bridge in this mode both interconnected networks create one whole on the hardware level e g computers with Microsoft Windows operating system will see each other in the network neighborhood A built in DHCP BOOTP server allows assigning of IP addresses network mask router addresses and other parameters to the network stations DHCP BOOTP Relay Agent listens for DHCP and BOOTP requests an
4. command sets up the PPP parameters when the DSL line works in the synchronous PPP mode Following options are available the lt port gt should be set to ppp0 O ppp lt port gt defroute on ppp lt port gt defroute off the command enables and disables respectively adding of the default route through the PPP interface after the connection is established O ppp lt port gt mtu lt value gt sets the maximum packet size that the modem may send through the PPP interface the final MTU setting depends also on the MRU setting on the remote router O ppp lt port gt mru lt value gt sets the maximum packet size that the router will accept to receive O ppp lt port gt ip lt local address gt lt remote address gt sets the IP addresses used during the PPP connection negotiation ppp lt port gt up1 lt command gt ppp lt port gt up2 lt command gt ppp lt port gt up3 lt command gt ppp lt port gt up4 lt command gt the to up4 options allow execution of up to four commands after the PPP link is established ppp lt port gt down1 lt command gt ppp lt port gt down2 lt command gt ppp lt port gt down3 lt command gt ppp lt port gt down4 lt command gt the down1 to down4 options allow execution of up to four commands after the PPP link is broken down O ppp lt ppp gt user lt username gt sets the username used during the PPP authorization if required by the
5. o dhcp add subnet lt name gt lt network gt lt address gt lt netmask gt Adds a net IP subnet to a given network For each IP subnet connected to the LAN or WAN interface an DHCP subnet should be added with the same IP addresses as configured on each of the interfaces Moreover additional IP subnets may be added those which are not set up on any of the interfaces but do exist in the same physical network or behind a DHCP relay dhcp add subnet local lan 10 0 0 0 255 0 0 0 dhcp add host lt name gt lt MAC address gt lt IP address gt Adds a static connection between hardware MAC and IP addresses The IP address must belong to one of the configured subnets Only this IP address will be assigned to the given MAC address dhcp add host server 00 50 13 2e 15 ca 10 0 0 5 dhcp add range lt start address gt lt end address gt Adds an IP address range from which addresses will be assigned to the network stations The address range must be contained inside one of the subnets dhcp add range 10 0 0 510 0 0 37 o dhcp add option lt option gt lt value gt Adds a global DHCP option sent to the requesting station Available options are routers network gateways usually the gateways should be separate for each subnet so they shouldn t be defined globally domain name domain name domain name servers DNS addresses filename name of the file containing the operating system next server server from which
6. possible e g there s no telnet client available or the modem s IP address is unknown the modem may be connected to the 5 serial port using a null modem cable After starting a terminal software e g minicom under Linux operating system Hyperterm under Microsoft Windows user gets the same access as through the telnet connection After pressing Enter the same command prompt appears Tahoe gt By default the console access isn t password protected but such protection may be enabled later using console password command 4 3 Commands 4 3 1 help Entering or help shows list of available commands 4 3 2 The arp command is used to configure the ARP table The arp alone shows the list of connections between IP and hardware MAC addresses Tahoe gt arp IP address Hardware address 10 0 0 2 00 50 04 0D 70 31 dynamic ARP table entries may be deleted using arp del Tahoe gt arp del 10 0 0 2 the IP address to be deleted should be typed instead of 10 0 0 2 Astatic ARP entry may be added using arp add Tahoe gt add 10 0 0 3 00 50 13 E9 5C 01 The dynamic hardware address resolution may be disabled using the ifconfig command If it is disabled only those stations may connect to the modem whose IP and MAC addresses are entered into the ARP table using the arp add command This way an unauthorized network access may be pro
7. remote router O ppp lt port gt password lt password gt sets the password used during the PPP authorization if required by the remote router ppp lt port gt debug on ppp lt port gt debug off enables and disables respectively the syslog debugging of the PPP link eI OE OOOO OOOO 4 3 21 ps Show the processes list 4 3 22 reboot Reboots the modem All unsaved changes to the configuration will be lost 4 3 23 route The route command is similar to analogous Linux command It is used to configure the IP routing The route alone shows the current routing table It may be modified using following commands route add lt address gt lt interface gt adds the route to a specific host directly through the interface the station with this address has to be in the network directly connected to that interface O route add lt address gt gw lt gateway gt adds the route to a specific host through a gateway route add net lt address gt netmask lt network mask gt lt interface gt adds the route to a subnet with given address and network mask directly through a specified interface route add net lt address gt netmask lt network mask gt gw lt gateway gt adds the route to a subnet with given address and network mask through a specified gateway route add default gw lt address gt adds the default route through a given gateway route del lt address gt
8. 9600 bps 8 data bits 1 stop bit no parity no handshaking Pin Name Description 1 DCD carrier detect transmission readiness signaling 2 RXD data received from the PC 3 TXD data sent by the modem to the PC 4 DTR active when the PC is switched on 5 GND signal ground 6 DSR active when the modem is switched on 7 RTS used by the PC to inform that is has data to send 8 CTS used by the modem to permit data transmission 9 RI ring indicator signal used in telephone modems gt After connecting the console to the PC and running a terminal software user has the same access to the modem functions as through atelnet connection see chapter 4 2 3 FastEthernet The FastEthernet interface is used to connect the modem to the Local Area Network It may work at speeds of 10 Mbps 1OBase T or 100 Mbps 100Base T in either full duplex or half duplex mode The mode of transmission is selected automatically Modem should be connected to a Ethernet switch or a hub using a straight patch cord or to a PC a router or an uplink port in a switch using a crossed over one After connecting a LED named LAN Link should be lit In the Tahoe 681 682 modems the FastEthernet interface has following status LEDs O LAN Link lit when modem is connected to a LAN O LANAct LANactivity blinks when data is sent or received O 10 100M LAN connection throughput lit when 100 Mbps connection speed is neg
9. O 1 1 etc VLAN interface aliases fri fr2 etc Frame Relay PVCs the number after fr is the DLCI of a given PVC pppo PPP interface used when the DSL link works in the PPP mode wano HDLC interface used when the DSL link works in the Cisco HDLC mode This command has similar syntax as the Linux ifconfig ifconfig lt interface name gt lt IP address gt netmask lt network mask gt bcast lt broadcast address gt static dynamic bridge on off The ifconfig alone displays information about the active interfaces Entering ifconfig lt interface name gt shows information about a certain interface An information about interface s IP address number of packets and bytes send and received number of transmission errors and other important data is displayed An IP address may be assigned to an interface together with subnet mask and broadcast address A dynamic ARP may also be enabled or disabled The bridge parameter allows to include or exclude certain protocol from bridging when the modem works in the bridge mode 4 3 13 ipchains The command is used to control the firewall and the network address translation NAT called also masquerade that is giving a network an access to the Internet using only one real IP address o ipchainsadd adds an entry the end of the list ipchainsinsert addsan entry atthe beginning ofthe list ipchains del
10. arameter may be one of u admin full access to the device u read only permits only reading of the configuration and the statistics user mode lt single multi gt selects the working mode to either single or multi user 4 3 32 4 3 32 Displays current firmware version 4 3 33 4 3 33 watchdog The watchdog command gives additional control over the modem s unpredicted behavior i e a misconfiguration disabling further communication with the modem The modem uses the ping command to check the availability of certain IP addresses and reboots if one of them doesn t answer OOOO The command has following syntax watchdog on enables the watchdog watchdog off disables the watchdog watchdog lt interval gt lt amount gt lt wait gt lt IP address gt lt additional IP address gt configures the watchdog After lt interval gt seconds the modem sends lt amount gt of pings to the lt IP address gt and the lt additional IP address gt if set waiting lt wait gt seconds after each of them If there is no answer for any ofthe pings sent to the first address or for any of the pings sent to the second address then the modem is rebooted 4 3 34 write Saves the current configuration to the EEPROM and displays an information about the EEPROM usage If the configuration is to large to be stored some settings should be deleted like static ARP entries DHCP options et
11. between separate networks The DHCP and BOOTP protocols work only within one physical subnet The station using such protocols doesn t know its IP address yet so its packets cannot be routed to other networks Relay Agent listens for such requests and forwards them to a DHCP server which may be placed anywhere in the network 4 3 7 1 4 3 7 1 Review of the settings Entering dhcp alone displays current server settings Here is an example Tahoe gt dhcp DHCP BOOTP server default lease time 43200 max lease time 86400 network lan eth0 default lease time 43200 max lease time 86400 domain name tahoe pl subnet local 10 0 0 0 255 255 255 0 default lease time 43200 max lease time 86400 filename vmlinuz 2 2 19 next server 192 168 0 5 routers 10 0 0 1 domain name servers 192 168 0 4 domain name tahoe pl address ranges 10 0 0 3 10 0 0 15 relay server 192 168 0 5 67 4 3 7 2 Basic DHCP server configuration rules Before starting using DHCP server please read following guidelines the configuration is organized in a hierarchical manner the most general group of settings is network the physical network connected to the modem Any number of subnets may exist within a network Inside an subnet IP address range may be selected these addresses will be dynamically assigned to the network stations A static connection between an IP address and a hardware address may also be
12. c 5 Technical data processor Motorola PowerPC 50MHz o memory 4MB SDRAM o network protocols IP TCP UDP ICMP TFTP SNMP DHCP BOOTP RFC 1490 PPP Frame Relay Cisco HDLC IEEE 802 1q Frame Relay signaling ANSIT1 617 Annex A ITU Q 933 Annex Cisco LMI o G shdsl interface connector RJ 11 standards ITU G 991 2 G shdsl ITU G 994 1 modulations TCPAM 32 TCPAM 16 TCPAM 8 TCPAM 4 PAM 16 PAM 8 PAM 4 PAM 2 o throughput Tahoe 681 64 4864 kbps Tahoe 682 128 9728 kbps o Ethernet interface 10 100Base T RJ 45 connector serial console RS 232 DB9 M connector dimensions 200 mm width x 45 mm height x 130 mm length o power supply Tahoe 681 15V 260 mA 3 5W Tahoe 682 15 V 360 mA external power supply included environmental conditions storage temperature 20 C to 65 C humidity 5 10 95 operation temperature 0 C to 40 C humidity 85 6 Declaration of Conformity TAHOE Piotr Kaczmarzyk ul Uniwersytecka 1 50 951 Wroclaw Poland We declare that the products Tahoe 681 and Tahoe 682 comply with the regulations of the following European Directives o 73 23 EEC low voltage safety requirements o 89 336 EEC EMC requirements o 99 5 EEC radio 8 telecommunication terminal equipment requirements The compliance of Tahoe 681 and Tahoe 682 with the requirements of the above mentioned directives is ensured by complete ap
13. d forwards them to a central server Modem supports Network Address Translation i e makes it possible for a whole network to access Internet using only one real IP address Additional firewall improves the network security by blocking eI oO unwanted traffic basing on IP addresses TCP or UDP ports and protocols appearing in the received packets The system firmware is stored in the Flash memory it is possible to update it using the TFTP protocol The configuration is stored in the EEPROM memory 2 Interfaces Following connectors are found on the rear panel of the modem serial LAN power power G shdsl console FastEthernet connector switch 2 1 G shdsl It is a 6 pin RJ 11 connector used to connect the leased line In Tahoe 681 the line should be connected to pins 3 and 4 In case of Tahoe 682 one line should be connected to pins 2 and 3 while the other one to pins 4 and 5 The first and second line may be interchanged between modems that will be automatically detected The polarization of a line is not important Pin Tahoe 681 Tahoe 682 1 2 line 1 3 line 1 line 1 4 line 1 line 2 5 line 2 6 2 2 2 Serial console The RS 232 serial console is used for modem management It has a DB9 M connector and works as a DTE i e a null modem cable should be used to connect it to a PC Three lines bolded are sufficient Terminal settings are
14. e Amplitude Modulation The latter is more efficient It is recommended to use the 32 TCPAM modulation which provides the best results The remaining line codings are available to provide compatibility with others manufacturers equipment Moreover 32 TCPAM allows throughputs from 256 kbps to 4864 kbps per line while 16 TCPAM from 64 kbps to 2304 kbps The Auto setting forces use of 32 TCPAM for speeds higher than or equal to 256 kbps per line and 16 TCPAM for lower rates 3 4 Write configuration to EEPROM Every change to the configuration will be lost after reboot or power off unless the settings are written to the EEPROM After reaching this option just press Enter to save them 3 5 IP address and network mask on ethO interface As a factory default the Ethernet interface of the modem has the IP address set to 10 0 0 1 and the network mask to 255 0 0 0 After connecting to this address using telnet further configuration can be done The IP address may be changed however using the keyboard It s useful when the IP address has been changed and then forgotten After pressing Enter up and down buttons may be used to change the first octet of the IP address Then after pressing Enter second third and fourth octet may be set Afterwards the network mask may be changed Up and down keys lengthen or shorten it respectively by one bit Pre
15. ecific rule has to be inserted before the general one as in following example ipchains add s 215 16 11 0 24 deny ipchains insert s 215 16 11 5 accept Commands above inhibit the access for the whole 215 16 11 0 24 subnet exceptthe 215 16 11 5 address Note The specific accept rule concerning one IP address has to be inserted before the general one concerning the whole subnet either using the insert command as in the example above or by adding the specific rule first and then the general one Otherwise the router will always apply the first rule and will never reach the second one as the packet coming from 215 16 11 5 fits both of them and ifthe general one isfirst then it will be applied More examples ipchains add d 0 0 0 0 0 80 80 p tcp deny Inhibits access to the port 80 on all external servers ipchains add s 192 168 0 0 16 Enables masquerade for the 192 168 0 0 16 subnet other addresses are passed unchanged 4 3 14 lang Selects the language used to display messages during the telnet or console connection and on the LCD eI 2 3 o lang o0 Polish o lang 1 English 4 3 15 Icd The command may be used to customize the LCD information e g to ease modem identification led 1 lt text gt sets the text displayed on the first line of the LCD o led 2 lt text gt sets the text displayed on the second line led show shows current settings Icd clear disab
16. ess gt if the server is enabled the access to it may be limited to a certain IP address If this address is set to 0 0 0 0 then the access isn t limited 4 3 29 timeout The command sets the inactivity time in seconds after which the telnet connection is closed It has following syntax timeout lt during the session gt lt during logging in gt The first parameter is used after the logging in and the second one optional during the log in Entering 0 disables the timer These settings are also applied to the serial console if its access is password protected using the console passwd on command 4 3 30 uptime w Shows the time elapsed since the modem booting and the current processor temperature 4 3 31 4 3 31 user The user command is used to manage users having access to the modem The modem may work in two different modes single user only the password is necessary to access the modem The user that logs in has the full access to the device multiple users allows creating many users with different names passwords and access levels The user command has following syntax user list shows the user list user add lt name gt adds a new user user del lt name gt removes an user user passwd lt name gt lt password gt changes the user s password user level lt name gt lt access level gt changes the users access level The lt access level gt p
17. fied group network subnet or host It has two forms o dhcp network add lt option name gt lt value gt o dhcp network del lt option name gt lt value gt instead of network a subnet or host may be given options are described in 4 3 7 4 e g dhcp network add domain name tahoe group com Options are valid only for a given network subnet or host Moreover two other parameters can be set o dhcp network default lease time lt value gt Sets the time in second for which the IP address is assigned to the station After that time the station must inform the DHCP server that it still uses that address Otherwise the address will be considered as unused This timeout prevents blocking an IP address when a station is switched off without releasing that address o dhcp network max lease time lt value gt A station may request other lease time the negotiated time may not be higher than this setting 4 3 7 8 4 3 7 8 dhcp default lease time lt value gt dhcp max lease time lt value gt These commands are similar to those described in the previous paragraph but their meaning is global 4 3 8 dsl This is a group of commands used to configure the DSL link Following options are available o dsl fr ppp hdlc selects the protocol used to send data through the line Frame Relay synchronous PPP or Cisco HDLC The Cisco HDLC is recommended if the modem has to work in the bridge
18. hibited 4 3 3 bridge The bridge command enables or disables the bridge mode in which two interconnected LANs create one whole in the hardware layer The stations in both LANs behave like if they were connected to one Ethernet switch e g PCs working under Microsoft Windows operating system will see each other in the network neighborhood Three settings are available off regular TCP IP routing on bridge enabled but the modem is still available under its IP address and thus may be managed remotely eI 1 3 o transparent completely transparent bridge inaccessible under its IP address this mode may be disabled only through the serial console or the LCD and keyboard Entering bridge list displays a list of MAC addresses with the name of the interface on which certain address was heard Note To make bridging work properly interfaces used in the process have to be indicated To enable bridging on a certain interface enter ifconfig lt interface name gt bridge on Note enable bridging the Cisco HDLC link protocol should also be selected using dsl hdlc command 4 3 4 The con command erases whole configuration from the EEPROM After rebooting the modem it will return to its factory defaults Until the reboot it will continue to run with its current settings which can be saved again using write command 4 3 5 config The config command displays curren
19. isconects from the modem 4 3 10 fr A group of commands used to configure the Frame Relay protocol parameters Following options are available O fr ansi q933a cisco selects the LMI signaling ANSI T1 617 Annex D ITU Q 933 Annex A or Cisco LMI o fr 391 lt value gt sets the T391 parameter i e the number of failed retries during the communication through the LMI after which the connection is considered as unusable O fr n391 lt value gt sets the N391 parameter i e the time between subsequent LMI retries fr debug on off enables and disables sending the Frame Relay debugging information through syslog 4 3 11 http The http command configures the built in WWW server It is used to provide an easy way to read modem statistics Server can be enabled or disabled by entering respectively http on or http off Moreover the access to the server may be limited by typing http host lt IP address gt Then the server is only reachable from the given IP address To remove the limitation a 0 0 0 0 address should be entered 4 3 12 ifconfig The command allows configuring the network interfaces Following interfaces are available o ethO Ethernet interface eth0 0 eth0 1 etc ethO interface aliases one physical interface may support several IP subnets eth0 1 eth0 2 etc VLAN networks LAN networks separated from each other although using the same cabling o eth0 1 0 eth
20. les custom display led first last gt the text may be shown either as the first screen the standard screen with modem type throughput and line state would be available after pressing Enter or as the last one after the screen with line parameters that is after pressing Enter three times The special characters may be used in the text displayed They will be replaced by appropriate values t modem type e g Tahoe 681 s total line throughput 1 first line state e g 2 second line state Tahoe 682 only 4 3 16 The masq command displays a list of masqueraded connections The list consists of source and destination addresses the port assigned by the modem the time remaining to the removal of an entry in case of connection inactivity and the amount of remaining free table entries that may be used for new connections Both ports and IP addresses are printed as hexadecimal numbers 4 3 17 4 3 17 Mem shows the memory usage statistics The free entry is the most important it shows how much free memory is left 4 3 18 netstat 4 3 18 Shows list of active TCP connections 22 4 3 19 ping Checks the availability of a device with selected IP address For example ping 10 0 0 2 gives the time necessary to send packet to the 10 0 0 2 station and back or reports its unavailability 4 3 20 ppp The ppp
21. line rate may be increased without causing any problems with the synchronization When the NMR is less than 0 dB modems will be unable to bring the link up It is the best practice to keep the NMR equal to or higher than 5 dB so the error rate will be unnoticeable Otherwise the packets will be lost due to bit errors and the retransmission would be necessary thus decreasing the overall effective throughput This parameter is also valid only when the lines are fully synchronized In case of Tahoe 682 modem both lines NMRs are shown Pressing Enter again will return to the main screen with the throughput and modem state ee 4 Modem configuration using telnet or serial console 4 1 Telnet connection To connect to the modem the network interface in your PC has to be in the same IP subnet as the modem By default modem s Ethernet interface is set to 10 0 0 1 address and 255 0 0 0 netmask so the PC may have IP address set to 10 0 0 2 and the same netmask If the modem was already configured and the routing table is correctly set up a telnet connection to its IP address is possible from anywhere in the network After connecting a password prompt will appear User Access Verification Password The default password is Tahoe case sensitive If the password entered is correct acommand prompt will appear Tahoe gt 4 2 Serial console If the telnet connection is not
22. mode o dsl speed lt value gt lt second line gt sets the line throughput In case of Tahoe 681 modem the value should be selected from 64 4864 kbps range with 64 kbps step In Tahoe 682 modems the throughput may be set in two ways either by giving the total rate from 128 9728 kbps range or by giving separate values selected from 64 4864 kbps range for each of the lines The latter possibility is useful if the lines differ in their quality New throughput will be set after entering dsl reset command o dsl type master slave sets the modem type master or slave New mode is set after entering dsl reset command Always one modem should be set as a master while the other one as a slave o dsl mod auto tcpam32 tcpam16 tcpam8 tcpam 4 16 pam8 pam4 pam2 selects line modulation The TCPAM32 modulation is recommended as it is the most efficient the rest is available to provide compatibility with other manufacturers devices Moreover TCPAM32 allows throughputs from 256 kbps to 4864 kbps per line while TCPAM16 from 64 kbps to 2304 kbps The auto setting forces use of TCPAM32 for speeds higher than or equal to 256 kbps per line and TCPAM16 for lower rates dsl reset resets the DSL connection the synchronization is performed from the beginning Entering dsl alone displays current settings 4 3 9 exit quit The command closes the configuration session and d
23. ng for the addresses it has in its static table If the request comes from another MAC address than in the modem s ARP table it will send an answer with the correct MAC address Such request is sent by the PCs working under the Microsoft Windows operating system during the boot up If the ARP reply from the modem comes the PC will show a message that this address is occupied which will make an illegal use of that IP address impossible The strictarp mode may be disabled using strictarp off 4 3 26 4 3 26 syslog The modem may send the messages about its status and important events to a syslog server To configure syslog logging following commands may be used o syslog on enables logging o syslog off disables logging o syslog host lt IP address gt sets the IP address to which the messages will be sent el 228 4 3 27 telnet 4 3 27 The command allows limiting the telnet access to the modem The access may be enabled or disabled by entering telnet on or telnet off respectively Moreover the access may be limited to a certain IP address telnet host lt IP address gt If the IP address is set as 0 0 0 0 then the access is possible from anywhere in the network 4 3 28 tftp The command configures the TFTP server used for the firmware upgrade Three options are possible tftpon enables the TFTP server o tftp off disables the TFTP server o tftp host lt IP addr
24. otiated Onthe right two WAN status LEDs are present blinking when data is respectively received from or sent to the DSL line O WAN Rx WAN Receive WAN Tx WAN Transmit 3 Modem configuration using built in keyboard and LCD The easiest way to configure a modem is to use the four button keyboard and the LCD After switching the power on an information about the modem type the line throughput and state will be displayed The messages are different for Tahoe 681 and Tahoe 682 modems Four letter code on the right describes the DSL line state o BOOT booting of the G shdsl transceiver IDLE transceiver inactive DOWN transceiver active line not synchronized SYNC line synchronized data may be transmitted In case of Tahoe 682 modem the top code describes the first line while the bottom the second one On the right of the display there is a keyboard with down Escape and Enter keys By pressing up down buttons you may browse the configuration menu speed setting modem type setting Master Slave line modulation selection storing settings in the EEPROM memory setting the IP address and network mask on the ethO interface selection of the language connection reset modem reset bridge mode toggling Each pressing of the Escape button causes the return to the primary display with modem type and state Pressing of the Ente
25. plication of the following harmonized European Standards EN60950 2000 o EN55022 1998 EN61000 6 1 2002 o EN61000 6 3 2002 Signed Piotr Kaczmarzyk Position Director Signature OAH Ll a SZA Date 30 Apr 2004 l Place Wroclaw Poland 2004 Tahoe All rights reserved Other trademarks of other companies are used only for explanation and to the owner s benefit without intent to infringe Tahoe assumes no responsibility for any errors or omissions that may appear in this document Tahoe makes no commitment to update the information contained here and may make changes at any time without notice TAHOE Uniwersytecka 1 50951 Wroctaw Poland phone 48 50 100 7362 fax 48 71 344 2642 http www tahoe group com
26. r button selects given menu option gt 1 3 1 Throughput setting After pressing Enter the throughput may be set using up down buttons In Tahoe 681 modem it may be chosen from 64 4864 kbps range with 64 kbps step while in Tahoe 682 from 128 9728 kbps range with 128 kbps step In the latter case the actual throughput of each line is half of the throughput set Different rates for each line may be set using the serial console or the telnet connection see chapter 4 After choosing the right speed and pressing Enter modem will resetthe connection and renegotiate it with new settings NOTE The same throughput must be set on both modems 3 2 Modemtype After pressing Enter the modem type may be selected either Master HTU C or Slave HTU R After selecting the type and pressing Enter again the connection will be reset and renegotiated with new settings NOTE Always one modem has to be set as a Master and the other one asa Slave 3 3 Line coding After pressing Enter the G shdsl line coding signal modulation may be chosen The number 32 in the example above means the number of values encoded in one symbol 32 5 bits per symbol The higher this number is the lower is the signal frequency which gives better immunity for signal attenuation and higher reach The second part PAM or TCPAM means either the Pulse Amplitude Modulation or Trellis Coded Puls
27. removes an entry o ipchains list displays current settings ipchainsflush removes all entries from the list After the add insert or del option following parameters should be given O s lt source subnet gt lt netmask gt port range Defines the source addresses which this entry concerns If this parameter is omitted then the entry concerns all source addresses O d lt destination subnet gt lt netmask gt port range Defines the destination addresses which this entry concerns If this parameter is omitted then the entry concerns all destination addresses O p lt protocol gt optional Optionally the application of this rule may be limited to a certain protocol O y optional The rule may be applied to the TCP SYN packets only i e the packets that initiate the TCP connection It allows inhibiting the incoming connections while the returning packets for the outgoing ones will be passed O m lt IPaddress gt By default during masquerade an outgoing interfaces IP address is used The option above allows forcing use of another address accept deny information what to do with a packet that conforms to a given rule accept discard masquerade Note The modem always chooses the first matching rule from the list So if the more general rule comes first and the more specific is later then the first one will be applied and the last one ignored Thus the sp
28. set Each group network subnet has its own options Creating a new group e g subnet within a network causes copying of the options from the parent group e g if the lan network has a domain name option after adding a local subnet within lan the option will be automatically copied it may be modified or deleted later onthe beginning a network for each interface should be created in each of the networks an IP subnet should be created according to IP subnets connected to that interface modem may not have the routing set up to each of them it s enough that they are in the same physical network now IP ranges and static IP entries may be added 4 3 7 3 dhcp on off relay DHCP BOOTP server may work in one of three modes on the server in enabled and answers to the requests off the server is disabled relay the server is disabled but the relay agent is enabled and listens for the requests to be forwarded to other DHCP server 4 3 7 4 dhcp The commands add a network subnet IP range etc Following variants are supported o dhcp add network lt name gt Adds a new physical network connected to the modem s interface There should be the same number of networks and interfaces The network interface connection will be determined later while adding the IP subnets dhcp add network lan
29. ss Enter again to approve new settings or Escape to cancel the operation 3 6 Languageselection After pressing Enter the language used on LCD and during the telnet connection may be changed 3 7 Connection reset 3 7 After pressing Enter G shdsl link will be disconnected and negotiated again 3 8 Modem reset After pressing Enter the whole modem is rebooted If some settings were not saved to the EEPROM they will be lost 3 9 Bridge mode This option enables or disables the bridge mode in which two interconnected LANs create one whole in the hardware layer Three settings are available off regular TCP IP routing bridge enabled but the modem is still available under its IP address and thus may be managed remotely transparent completely transparent bridge 3 10 3 10 Line parameters The Esc button returns to the main screen with modem type throughput and link state While having this screen displayed you may press Enter to display line attenuation in dB proper value appears only after the line synchronizes In case of the two pair modem Tahoe 682 both lines attenuations are shown Pressing Enter again will show so called Noise Margin or Signal Noise Ratio This is the difference between the useful signal and the background noise It may be used to estimate how much the
30. t configuration The command output may be entered on another modem to make an exact copy of the configuration 4 3 6 console This command is used to enable or disable password the protection of the serial console By default the console is unprotected and user has full access to the modem By entering console passwd on the password requirement is enabled and modem will ask for it in the same manner as during the telnet connection To disable password protection type console passwd off 4 3 7 dhcp 4 3 7 The dhcp command is used to configure DHCP BOOTP server and relay agent The server is used to assign IP addresses network masks gateway and DNS addresses and other parameters to the 2 lt lt network stations It is easy to reconfigure a network that uses a DHCP server it is enough to change server settings and every station will automatically retrieve new configuration The BOOTP protocol is an earlier and simpler version of DHCP Its common use is booting of diskless workstations A workstation uses BOOTP to get its IP address and other network parameters together with TFTP server address from which the operating system may be downloaded The DHCP protocol may deliver more working parameters including domain name DNS address print server syslog server X Window fontserver MTU and TTL settings and many others DHCP BOOTP Relay Agent transfers DHCP and BOOTP requests and replies
31. the mentioned above file will be downloaded using TFTP dhcp add option domain name tahoe group com ee F o dhcp add relay lt address gt lt port gt Adds a DHCP server address to which the DHCP requests are forwarded when the Relay Agent mode is enabled The lt port gt parameter is optional its default value is 67 dhcp add relay 192 168 0 3 4 3 7 5 dhcp del 4 3 7 5 The command deletes a network subnet address range etc o dhcp del network lt name gt o dhcp del subnet lt name gt o dhcpdel host lt name gt The commands above delete respectively a network an IP subnet or a host a static IP MAC connection with given name o dhcp del relay lt address gt Deletes a DHCP server address used in the Relay Agent mode o dhcp del range lt start address gt lt end address gt Deletes an IP address range assigned to the network stations o dhcp del option lt name gt lt value gt Deletes a global option Besides the option name its value should also be given because some options may have more than one value e g domain name servers routers etc 4 3 7 6 dhcp rename 4 3 7 6 The command changes the name of a network subnet or host o dhcp rename network lt old name gt lt new name gt o dhcp rename subnet lt old name gt lt new name gt o dhcp rename host lt old name gt lt new name gt 4 3 7 7 dhcp network subnet host 4 3 7 7 The command adds or deletes an option within a speci
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