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1. Fig 76 RJ TPDU normal format for classes 1 and 3 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 113 8 li_4 Length Indicator Layer 4 1 TPDU Code 0 0 0 0 2 dst_ref Destination Reference 3 dst_ref Destination Reference 4 YR TU No Bits 25 32 7 YR TU No Bits 17 24 6 Header YR TU No Bits 9 16 7 YR TU No Bits 1 8 8 Credit Bits 9 16 9 Credit Bits 1 8 10 Fig 77 RJ TPDU expanded format for class 3 Fixed portion li_4 Length of the Layer 4 Headers in Bytes the li_4 Bytes exclusively TPDU_ Code 0101 5 h dst_ref Insert here the src_ref of the remote station YR TU No Shows the next expected ED TPDU No 1099 002 Fax 49 911 54427 27 e 49911 54427 0 e D 90482 N rnberg e Ostendstra e 115 e INAT GmbH 114 The Protocols of Layer 4 Error ER This TPDU is only used for classes 1 and 3 It contains the reason for the rejection 8 1 li_4 Length Indicator Layer 4 TPDU Code dst_ref Destination Reference dst_ref Destination Reference 4 m Header Reason of Rejection 5 Variable Portion 6 li_4 6 Fig 78 ER TPDU for classes 1 and 3 Fixed portion li_4 Length of the Layer 4 Headers in Bytes the li_4 Bytes exclusively TPDU_ Code 0111 7h dst_ref Insert here the src_ref of the remote station
2. 6 Option to transport data with special priority Both sender and receiver must have the option of providing special handling for urgent data 7 Status report The transport layer should be able to tell the user the status of the transport connection e g amount of throughput length of the average delay addresses being supplied and so on This service is not offered by the ISO standard 8 Security It is conceivable that the transport layer may provide security services e g verification of the sender and receiver or encryption decryption of the data This service is not offered by the ISO standard The following functions are provided by layer 4 in accordance with the ISO standard O Connection establishment and disconnection Example Communication between PC and file server When a user issues a login command to the PC the transport layer of the PC sends a request to the file server to establish the connection After connection establishment has been 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 87 confirmed by the file server the actual login procedure can be started However this takes place in a higher layer which uses layer 4 for data transportation O Data transfer After the connection has been established all further data of the higher layers are transported back and forth with TPDUs i e transport data c
3. DLC DLC Header DLC Frame size 162 A2 hex DLC Destination Station S5 TCP IP 2 IDLC Source Station 55 TCPAP 1 DLC IP IP Header Leitrechner IP Version 4 header length 20 bytes IP Type of service 000 routi Lieu ES Time Own Address Dest Address oO 7 0 00512 S5 TCPAP 2 Leitrechner 0 norm f 182 0 00006 Leitrechner S5 TCPAP 2 from 195 180 213 189 IP Total length 1 FETTE S5 TCPAP 2 from 195 180 213 173 Eata iaaa 0 00382 S5 TCP IP 2 S5 TCPAP 1 from 195 180 213 172 z j San 185 0 02689 Leitrechner 5 TCP IP 2 Data DestRef E00 EOT 0 T lasi 186 0 00262 SS5 TCPAP 2 Leitrechner Ack DestRef F00 SrcC Fragment offset 187 0 00396 Roboter 1 Roboter 2 from 195 180 213 190 Time to live 2 188 0 00377 Roboter 2 Roboter 1 from 195 180 213 170 Protocol 6 TC 189 0 02145 SS TCPAP2 S5 TCPAP 1 from 195 180 213 172 Header checks 190 0 02735 Leitrechner S5 TCPAP 2 CR SrcRef 1900 Dest Source addr 191 0 00007 Leitrechner 55 TCPAP 2 Ack DestRef 1400 Srct Destination adc 192 0 00434 S5 TCP IP 2 Leitrechner DR DestRef 1900 Srcz No options H1 Connections CP Source port 400 Dest Address Refl Ref Own TSAP CP Destination port 4525 S5 TCPAP 2 0A00O 0000 lt FAHI gt CP Sequence number 5042133 S5 TCPAP 1 0000 D0A00 CP Acknowledgement number 23093 CP Data offset 20 bytes D5 AC 01 90 11 AD 00 4C EF D5 00 00 5A 35 50 un Statistics Bee 00 11 B8 CF 00 00 4D 4
4. class 4 0 normal format in all classes the TPD number as well as the confirmation numbers have a length of seven bits 1 extented format in the classes 2 3 4 the numbers have a length of 31 Bits O with flow control in class 2 1 without flow control in class 2 1099 002 Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 93 Sending machine A 0 77 B A A may send seven TPUDs 6 SA 2 N 0 N 1 0 Py a A shrinks its window with f each transmission 6 im 2 ww 4 0 DS 0 7 oe A adjusts its window with 6 E each credit WwW 5 eg 4 N 5 N 6 o Ne LA f A exhausts its credit 6 i 2 f 5N 3 4 0 n MO 1 i A receives new credit 6 gt 2 ws 3 4 Quelle Stallings data and computer communications Fig 62 Example of a credit Variable portion Receiving machine B B is prepared to receive seven TPDUs number 0 through 6 B acknowledges 3 TPDUs but is only prepared to receive 1 additional TPDU beyond the original budget i e B will accept TPDU 3 through 7 B acknowledges 3 TPDUs and restores the original credit Definition of the variable portion permits additional information on the desired transport connection to be transferred to the partner station Up to 14 different transport parameters can be t
5. dst_ref Destination Reference dst_ref Destination Reference EOT TPDU Number Variable Portion Checksum Data 6 9 10 li_4 9 nr Header Fig 70 ED TPDU normal format for classes 1 2 3 and 4 INAT GmbH Ostendstra e 115 e D 90482 N rnberg T 49911 54427 0 1099 002 Fax 49 911 5 44 27 27 Description of the ISO Communication Protocols 107 li_4 Length Indicator Layer 4 TPDU Code 0 00 0 2 dst_ref Destination Reference 3 dst_ref Destination Reference 4 EOT TPDU No Bits 25 31 5 m Header TPDU No Bits 17 24 6 TPDU No Bits 9 16 7 TPDU No Bits 1 8 8 Variable Portion 9 12 Data 13 li_4 12 Fig 71 ED TPDU expanded format for classes 2 3 and 4 Fixed portion li_4 Length of the Layer 4 Headers in Bytes the li_4 Bytes exclusively TPDU_Code 1111 F h dst_ref Insert here the src_ref of the remote station EOT EOT is 1 if the last TPDU of a TSDU which was possibly segmented by the transport layer is content of the data TPDU ED TPDU No Is a Modulo number which increases by one with each data TPDU The number is used for flow control Just in the expanded format each TPDU number should appear only once during a trouble free transmission that means repeats are not necessary Variable portion Checksum The checksum is calculated from all elements of the TPDU and consists of one record of two modulo 2
6. e Byte 1 81 h format identification IEEE basic format e Byte 2 bits 0 to 4 00001 Class I LLC 00011 Class II LLC e Byte 3 bits 1 to 7 Receiver s window size Specifies how many packets can be sent without having to wait for a higher N R N R W V S max with V S Sending count variable See also the next example MSB LSB 1 0 1 PF 1 1 1 1 Byte 1 Byte 2 Byte 3 Fig 46 The XID information field Example 1 N R 25 w 50 V S 72 The last acknowledgment is available for the packet with the sending count variable 25 i e N R 25 Since the size of the window is 50 50 additional packets can still be sent without acknowledgment When the sending count variable V S reaches 75 the sending LLC must wait for an acknowledgment i e 3 packets can still be sent It is obvious that a large window should be used when transmission paths are secure since many packets can be sent with a minimum of time spent on acknowledgment However if for example an error occurs in the 26th packet all packets sent after that i e in our example 47 packets must be sent again This requires additional sending time Example 2 Sending l format PDUs with acknowledgment LLC1 LLC2 Send to LLC2 I N S 0 P 0 N R 0 Send to LLC2 I N S 1 P 0 N R 0 Send to LLC2 I N S 2 P 0 N R 0 Send to LLC2 I N S 3 P 1 N R 0 Send to LLC1 RR F 1 N R 4 Send to LLC2 I N S 4 P 0 N R 4 S
7. yr_subseq yr_credit 8 Bytes 00001000 Window 32 Bits YR TU number of the received TPDU Bit 8 of the first byte is always zero In normal format only bits 1 7 of the fourth Byte are relevant Sub sequence 16 Bits The sub sequence parameters of the received AK TPDU are sent back If the sub sequence parameter is not used these bits are zero Credit 16 Bits The credit information of the received AK TPDU is sent back In normal format only bits 1 4 of the second byte are relevant 1099 002 e D 90482 N rnberg e 2 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 111 Expedited data acknowledgment EA This TPDU is used for flow monitoring The receiving station uses this TPDU to confirm correct receipt of an expedited data TPDU 8 1 li_4 Length Indicator Layer 4 1 TPDU Code 000 0 2 dst_ref Destination Reference 3 dst_ref Destination Reference 4 Header YR TU No 5 Variable Portion 6 li_4 6 Fig 74 EA TPDU normal format for classes 1 2 3 and 4 li_4 Length Indicator Layer 4 TPDU Code 0 0 0 0 2 dst_ref Destination Reference 3 dst_ref Destination Reference 4 EOT TPDU No Bits 25 31 5 Pr Header TPDU No Bits 17 24 6 TPDU No Bits 9 16 7 TPDU No Bits 1 8 8 Variable Portion 9 12 Data 13 li_4 12 Fig 75 EA TPDU expanded format for classes 2 3 and 4 1099 002 Fax 49 9
8. Fig 13 Dialog for settings 39 Fig 14 Dialog for setting the capture options 40 Fig 15 Dialog for the display filters 41 Fig 16 Frame list 42 Fig 17 Frame detail 44 Fig 18 Hex display 45 Fig 20 Hl connections 47 Fig 21 Suppression of Header information TCP IP settings in the Frame detail 48 Fig 22 Suppression of Header information TCP IP settings in the Frame detail 48 Fig 23 Suppression of TCP IP frames Frame List 49 Fig 24 Printing 50 Fig 25 NetSpector tool bar 51 Fig 26 Principal data conditioning for the INAT NetSpector 54 Fig 27 Layout of an 802 3 packet elements of the MAC layer 55 Fig 28 Layout ofthe LLC layer 57 Fig 29 Addresses of the LLC layer given in octets 58 Fig 30 Addresses of the LLC layer in bytes 58 Fig 31 SAPs in various stations 59 Fig 32 Equivalent ofthe arrangement shown above 59 Fig 33 General presentation of the control field 60 Fig 34 The UI control field 60 Fig 35 The XID control field 61 Fig 36 The test control field 61 Fig 37 I format PDU 62 Fig 38 RR control field 62 Fig 39 REJ control field 63 Fig 40 RNR control field 63 Fig 41 SABME control field 64 Fig 42 The DISC control field 64 Fig 43 The UA control field 64 Fig 44 The DM control field 65 Fig 45 The FRMR control field 65 Fig 46 The XID information field 66 Fig 47 Sending I format PDUs with acknowledgment 67 Fig 48 Typical arrangement of several subnetworks in one total network 68 Fi
9. It is used to indicate a temporary interruption of the information transfer on the receiver side All packets up to N R 1 are confirmed MSB 15 14 13 12 1110 9 8 7 6 5 4 3 2 LSB un Pro o o 0 0 Hol Fig 40 RNR control field The control field of the U format PDU The following PDUs have been defined in addition to the Ul XID and TEST PDUs of type 1 e SABME PDU e DISC PDU e UA PDU Type 1 PDUs should not be used in type 2 operation U format PDUs are used to implement the establishment and disconnection of a communication connection 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 64 The Protocols of Layer 2 The control field of the SABME PDU SABME stands for Set Asynchronous Balanced Mode Extended This PDU is used to initialize establishment of a connection A UA or a DM PDU is expected in response The poll bit must always be set Balanced mode means that two LLCs are establishing a connection and each LLC is responsible itself for the organization of its data stream and correction of errors Extended means that N R and N S may not be larger than 127 Fig 41 SABME control field The control field of the DISC PDU DISC stands for disconnect This PDU is used to implement the disconnection of a connection A UA or DM PDU is expected in response The poll bit must always be set Fig 42 The DISC control field The control field of the U
10. li_4 Length indicator Layer 4 1 TPDU Code 2 dst_ref Destination Reference 3 dst_ref Destination Reference 4 src_ref Source Reference 5 r Header src_ref Source Reference 6 reason 7 Variable Portion 8 li_4 8 Fig 65 The DR_TPDU 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 3 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 101 Fixed portion li_4 Length of the Layer 4 Headers in Bytes the li_4 Bytes exclusively TPDU_Co 1000 8 h de dst_ref Insert here the src_ref of the remote station src_ref No of connection of the DR sending station reason The reason for disconnection Following values are possible 10000000 Normal disconnection by the session layer 10000001 The remote station is not able to establish a connection due to traffic jam Darauf wird der Verbindungswunsch mit diesem DR Grund aufgehoben 10000010 Both station do not agree in the transport connection 10000011 A duplicate src_ref was detected 10000100 The references do not agree 10000101 Protocol error 10000111 There are no references available 10001000 The connection was rejected by the Network Layer 10001010 The length of the header or of a parameter is invalid Following values can be used in all classes 00000000 Reason not specified 00000001 Traffic jam of the transport connection 00000010 No session unit is connected t
11. 0 e Fax 49 911 544 27 27 Installation and Program Start 19 2 2 Software Installation 2 2 1 Installation under Windows NT and Windows 95 Note Installation of programs and drivers requires the rights of the system administrator 2 2 1 1 Installation of the Program under Windows NT and Windows 95 Step 1 Insert the floppy disk NetSpector NT Win95 Programm 1 Start the Setup exe program After preparation for the installation the start window of the installation appears Select Next The copyright screen appears Select Next again The programs and files which will now be installed on your system are displayed In the next window you will be asked for the destination directory under which INAT NetSpector is to be installed c INAT NetSpect is suggested as the standard directory If you agree continue with Next to specify the program group Otherwise start the file selection box first with Browse Note The directories which you specify are set up automatically if they do not exist Now specify the program group in which the icons of the INAT NetSpector are to be located Under Windows NT 3 5x this is a program group in the Program Manager Under NT 4 x this is an entry in the start menu The files are then copied After a while you will be asked to insert the floppy disk labeled NetSpector NT Win95 Disk 2 2 The final window of the installation tells you that INAT NetSpector has been installed s
12. 002 Fax 49 911 544 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 24 Software Installation 2 2 2 Installation under OS 2 The following steps are required to install the OS 2 version of the NetSpector network analyzer 1 Install the program on the hard disk 2 Install the driver for online captures 3 Perform system conclusion 4 Start computer again so that the changes will take effect 2 2 2 1 Installation of the Program under OS 2 e Place the floppy disk labeled NetSpector OS 2 Disk 1 2 in the floppy disk drive e Open the System folder Then open the command lines folder Start an OS 2 window or an OS 2 complete screen e Change the current drive by entering A or B depending on your floppy disk drive e Start the INSTALL EXE program by entering Install The installation will now be loaded e Click the Continue button The Install window shows you the product and the version number e Click the OK button to install the product e In the Install directories window select the entry NetSpector OS 2 You can also specify the directory in which the NetSpector network analyzer is to be installed C NETSPECT is the standard entry You will usually find that you can use this entry If you do not have enough memory space enter another drive or delete as many files as necessary The Disk space button will give
13. 189 Time 0 02145 Own 55 TCPAlP 2 Dest S5 TCPAP 1 Bytes 60 ype IP from 195 180 213 172 to 195 180 213 173 TCP 4525 D 400 CMD lt ACK gt DLC DLC Header DLC Frame size 60 3C hex DLC Destination Station S5 TCP IP 1 DLC Source Station 5 TCP IP 2 DLC IP IP Header IP Version 4 header length 20 bytes IP Type of service 0 0O00 routine 0 normal delay 0 normal throughput gt awe D normal reliability Total length 40 bytes Identification 19418 Flags 0X 0 may fragment 0 last fragment Fragment offset 0 bytes Time to live 254 seconds hops Protocol 6 TCP Header checksum 3E32 OK Source address 195 180 213 172 Destination address 195 180 213 173 No options TCP Header Source port 4525 Destination port 400 Sequence number 23093 Acknowledgement number 5042241 Data offset 20 bytes Flags 0x10 0 No urgent pointer 1 Acknowledgement 0 No push 0 No Reset 0 No syn Window 1460 Checksum 195D OK F1 for help Fig 17 Frame detail 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 45 3 8 5 Hex Display The hex display is accessed with the menu item Frame Hex in the Window menu g Frame Hex Flag Lt 1x85 FIL Yil 0
14. 3 Starting the Capture 3 1 4 Deleting the Capture 3 1 5 Saving the Capture 3 1 6 Opening the Capture 3 2 The Station List 3 3 Symbolic Station Names 3 4 Statistics 3 5 Presettings 3 6 Capture Filter 3 6 1 Working with NetSpector without Filters 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg Ostendstra e 115 11 12 12 13 15 15 15 15 18 19 19 19 21 23 24 24 28 29 29 29 29 29 29 30 31 32 33 33 34 35 35 INAT GmbH 6 Contents 3 6 2 Working with Capture Filters 35 3 7 Settings and Options 39 3 7 1 Setting Noise and Time Display 39 3 7 2 Capture Options 40 3 8 Analyzing the Capture 41 3 8 1 Display Filters 41 3 8 2 Frame List 41 3 8 3 Meaning of the frame colours 43 3 8 4 Frame detail 43 3 8 5 Hex Display 45 3 8 6 H1 Display Filter and H1 Connections 46 3 8 7 TCP IP Settings 48 3 8 8 TCP IP Display Filter 49 3 8 9 Printing 50 3 9 Tool Bar 51 3 10 Keyboard Assignment 52 4 DESCRIPTION OF THE ISO COMMUNICATION PROTOCOLS 53 4 1 The Protocols of Layer 1 53 4 2 The Protocols of Layer 2 55 4 2 1 General 55 4 2 2 The MAC Layer 56 4 2 3 The LLC Layer 57 4 2 3 1 Presentation of the Individual Bits 58 4 2 3 2 The Control Field in Type 1 PDUs 60 4 2 3 3 The Control Field in Type 2 PDUs 62 4 3 The Protocols of Layer 3 68 4 3 1 General 68 4 3 2 Notes on the Connection of Local Networks 69 4 3 2 1 The Repeater 69 4 3 2 2 The Bridge 70 4 3 2 3 The Intelligent Br
15. 49 Connection of two LAN segments with repeaters 1099 002 Fax 49 911 5 44 27 27 e BB 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 70 The Protocols of Layer 3 4 3 2 2 The Bridge A bridge is a connection element for homogenous networks It implements the store and forward principle at the packet level The maximum length of the packets must be identical on both networks to be connected A bridge must be able to intermediately store at least one maximum length packet It can convert various MAC protocols e g IEEE 802 3 to IEEE 802 4 Acting as a filter when forwarding packets the bridge only forwards those packets whose destination address is not located in the source network S5 S2 S4 802 3 802 4 Bridge se LAN 1 LAN 2 Fig 50 Connection of two LANs with bridges Bridges are often used in backbone networks A backbone network consists of several subnetworks which handle the main communication and one common network which connects all subnetworks together Bridges are used to connect the subnetworks with the common network The rule that all station addresses must be unique also applies here Backbone m m m Ee m rm r 7 m Bridges LAN 1 LAN 2 LAN 3 LAN 4
16. 5 44 27 27 How the INAT NetSpector Works 13 1 4 System Prerequisites INAT NetSpector requires the following hardware and software IBM compatible 486 DX 2 66 or later Minimum of 12 MB of RAM 16 MB recommended Monitor screen resolution of 640 x 480 800 x 600 or better recommended The program occupies approx 1 MB of the hard disk 100 MB of free hard disk capacity is recommended for capture One free 16 bit AT slot for the network card Windows 95 Windows NT or OS 2 Warp operating system 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH Installation and Program Start 15 2 Installation and Program Start 2 1 Hardware Installation 2 1 1 Installation on the Parallel Interface The software protection module Hardlock Il Twin Protection is a software protection module of the new generation As the first module of its type Hardlock Il can be used for both the parallel and the serial interface Its ease of handling is one of its primary features Just install Hardlock Il on the parallel interface of your computer and after a simple installation procedure you are ready to begin working with NetSpector Hardlock Il works with an ASIC i e Application Specific Integrated Circuit a new generation chip which cannot be bought off the rack This chip was developed especially for the complex requirements of both the parallel and serial interface This enable
17. 6 TPDU No Bits 9 16 7 TPDU No Bits 1 8 8 Variable Portion 9 12 Data 13 li_4 12 Fig 69 DT TPDU expanded format for classes 2 3 and 4 Fixed portion li_4 Length of the Layer 4 Headers in Bytes the li_4 Bytes exclusively TPDU_Code 1111 F h dst_ref Insert here the src_ref of the remote station EOT EOT is 1 if the last TPDU of a TSDU which was possibly segmented by the transport layer is content of the data TPDU TPDU No Is a Modulo number which increases by one with each data TPDU The number is used for flow control Just in the expanded format each TPDU number should appear only once during a trouble free transmission that means repeats are not necessary Variable portion Checksum The checksum is calculated from all elements of the TPDU and consists of one record of two modulo 255 sums Parameter Code 11000011 C3 h INAT NetSpector notation Checksum Parameter Length 2 Bytes 0000010 Parameter Value 2 Bytes Checksum 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 106 The Protocols of Layer 4 Expedited data ED This TPDU is used to sent expedited data via the transport connection Three different formats have been defined based on the transport class used This TPDU is not supported by class 0 connections Maximum data length is limited to 16 bytes li_4 Length Indicator Layer 4 TPDU Code 0 0 0 0
18. 90482 N rnberg e OstendstraBe 115 INAT GmbH 72 The Protocols of Layer 3 4 3 2 5 The Bridge with Source Routing This procedure is a simple implementation of a layer 3 protocol The sending station tells the bridge the route which the packet is to travel The bridge then converts the routing information to an address of its network and sends the packet to that address ISO does not use the principle of source routing since it has several disadvantages For example when routing involves WAN networks segmentation must be possible A fixed route does not permit detouring to other routes if the requested route has malfunctioned e g a bridge failure or overload is causing a malfunction This procedure is used for the IBM token ring since many small local subnetworks are to be connected via bridges The rule that all addresses must be unique also applies here s2 Mi Q E IH S1 Fig 52 Sample network for source routing 4 3 2 6 Source Routing Explained by Fig 52 Station 1 S1 wants to send station 2 S2 a packet The specified route is S1 B3 B4 B5 S2 The route could just as well have been S1 B1 B2 B4 B6 S2 How the route is determined is explained below 1st step S1 sends a packet in network 4 destination address S2 source address S1 routing information B3 B4 B5 final destination address S2 B3 and B1 recognize that this address is located
19. C K W I N T O 0 1 5 4 5 C R E E N S H O T E P S T H L P H ERE Fig 18 Hex display Here the frame is presented in hex and to the extent possible in ASCII The frame displayed in the Frame Detail is displayed in the Frame Hex If the frame is too large for the window you can scroll through it with the arrow or PgUp PgDn keys 1099 002 Fax 49 911 544 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 46 Analyzing the Capture 3 8 6 H1 Display Filter and H1 Connections The dialog box H1 Display Filter and the window H1 Connections are available for more detailed analysis of data communication between two Ethernet stations communicating via the H1 protocol H1 Display Filter Ed for Frame List Choosing a selection results that the Telegrams are suppressed lass Cancel Ch EE I DR S BE Help I Acknowledges Data I ExData I Eror I Eror Response MW bi for H1 Connections List Filters Off Only the Selected C All but not the Selected m Options in Frame Detail IV Show Sinec AP Data Fig 19 H1 Display filter Frame filter Certain types of frames can be filtered from the station list A check mark for a filter option means that this type of frame will not be indicated CR Connection Request see 91 CC Connection Confirm see 98 DR Disconnect Request see 101 DC Disconnect Confirm see 104 Acknowledges Acknowledges
20. D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 12 Supported Protocols 1 2 Supported Protocols Ethernet IEEE 802 3 Ethernet DIX V2 LLC NSAP H1 SINEC H1 ISO 8473 Layer2 2a MAC 2b LLC 3 4 AP TCP IP IP TCP UDP ARP RARP ICMP SMTP NetBIOS TCP DNS BOOTP OSPF 1 3 What You Can Select Captures can be stored on hard disk and reloaded at a later time Settings can be stored and loaded under a certain name Frames can be printed out with varying degrees of detail The Ethernet stations can be given speaking names Filters for capture display and analysis Variable size of the capture buffer Data can be written in a ring buffer so that the frames which were sent last can be captured Otherwise capture is halted when the buffer is full A certain network card can be selected so that several networks can be monitored Acoustic signal can be switched off via built in loudspeaker when a frame is received Size and position of the windows can be varied as desired Your settings are stored when the program is exited and restored when the program is started again Evaluation of the AP header information of the H1 frames can be enabled or disabled The acknowledge frames can be faded out for easier viewing of the data frames Certain connections of a capture can be selected or deselected in the H1 connection window 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911
21. LAN 5 LAN 6 LAN 7 LAN 8 LAN 9 Fig 51 The backbone network 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 71 Layer 3 also does not have to be used for LANs connected with bridges For source routing layer 3 is filled with routing information but this information does not meet the criteria of ISO standard 8473 see below There are three basic types in use today 4 3 2 3 The Intelligent Bridge By monitoring communication on both LANs the bridge learns all addresses on both LANs and automatically sets up a station list i e in Fig 50 stations S1 S2 S3 on LAN1 and S4 S5 S6 on LAN2 When S1 sends to S2 the bridge does not activate since it knows that communication is restricted to LAN 1 However when S1 sends to S5 the bridge intermediately stores the packet and after a frame check forwards the packet to S5 The bridge itself does not have a frame address This procedure makes it obvious that a bridge will not be able to handle the total data throughput of an 802 3 network i e theoretically 1 25 Mbyte sec 4 3 2 4 The Programmed Bridge The programmed bridge functions exactly like the intelligent bridge except that it does not automatically set up a station list Instead the network administrator tells the programmed bridge the addresses to be used 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D
22. Reason of rejection 00000000 No specific reason 00000001 Invalid parameter 00000010 Invalid TPDU type 00000011 Invalid parameter value Variable portion a Invalid TPDU Parameter Code 11000001 C1 h INAT NetSpector notation inv_tpdu Parameter Length n Number of bytes in parameter value field Parameter Value Contains the header of the rejected TPDU b Checksum The checksum is calculated from all elements of the TPDU and consists of one record of two modulo 255 sums Parameter Code 11000011 C3 h INAT NetSpector notation Checksum Parameter Length 2 Bytes 0000010 Parameter Value 2 Bytes Checksum 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 List of Figures 115 5 List of Figures Fig 1 NetSpector overview 9 Fig 2 How the INAT NetSpector works 10 Fig 3 Dialog for saving the capture 30 Fig 4 Dialog for opening the capture 31 Fig 5 Station list 32 Fig 6 Dialog for entering station names 33 Fig 7 Statistics 34 Fig 8 Dialog for the capture filters 35 Fig 9 Dialog for the station capture filters 36 Fig 10 Dialog for the station capture filters All but not the selcted ones 36 Fig 11 Dialog for capture filters for frame types 37 Fig 12 Dialog for the multicast capture filters 38
23. S Octets 10 to 12 Lowest acceptable value E S Bytes 13 to 24 Average throughput Octets 13 to 15 Destination value S E Octets 16 to 18 Lowest acceptable value S E Octets 19 to 21 Destination value E S Octets 22 to 24 Lowest acceptable value E S 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 97 j Residual error rate The residual error rate is the desired rate an d the minimum rate of unexplained data losses It is specified in exponents of 10 This parameter cannot be used for class 0 connections Parameter Code INAT NetSpector notation res_error Parameter Length 3 Bytes 0000 Parameter Values 1 Byte 2 Byte 3 Byte k Priority 10000110 86 h 0011 Destination value Lowest acceptable value TSDU size exponent to base 2 The priority specifies which transport connection is to be processed by the transport layer at what time Higher priority connections are given special treatment A connection with the priority of O has the highest priority This pa Parameter Code INAT NetSpector notation priority Parameter Length 2 Bytes 0000 Parameter Values I Transit delay rameter cannot be used for class 0 connections 10000111 87 h 0010 Integer 0 FFFFh Transit delay is the number of milliseconds which a TPDU may be delayed when it passes from layer 4 of the sender to layer 4
24. To assign a symbolic name to a station select the menu item Edit Station Names in the Edit menu and the following dialog appears Edit Stations Name Ed Cc Stations can be assigned by symbolic ame names Cancel Stations ddress and Name ii Help Accent eit Accept Available Stations 000000000000 SSTCP IP 2 FFFFFFFFFFFF 3com 0020D58001ED Siena 3com 002005800450 SPS1 INAT 002140000072 INAT 002140010002 SPS1 INAT 002140020002 SPS2 INST 002140050056 INAT S5 TCP IP 2 INST 00214005005F INAT S5 TCP IP 1 INAT 002140060072 INAT 002140060076 ZNYX OOCOSS5SEC5715 Delete Fig 6 Dialog for entering station names In the Available Stations list the Ethernet addresses with their company short code are indicated together with any symbolic names which have been entered After a single click on an entry in the Available Stations list this address appears in the Stations Address field You can enter the symbolic name maximum of 19 characters directly after the address Your entry is accepted with the Accept button You can also enter a 12 position Ethernet address directly in the Stations Address field and assign a symbolic name to it A station which is selected in the list is deleted with the Delete button All entries are saved when the window is exited 3 4 Statistics An active capture is indicated in the Statistics window by the red background of the windo
25. address related The global security level provides a generally known level It is not specified by ISO 8473 and may become the topic of a future ISO standard C3 h Quality of service one byte Designation Qual_of serv Similar to the security parameter ISO 8473 provides the possibility of individual encoding In contrast to security a global standard is defined The following quality criteria are defined by ISO 8348 ADD 1 e Transit delay e Cost determinants e Residual error probability Parameter length Variable one byte Parameter value Only the first byte is specified 00 h Reserved 40 h Source address related 80 h Destination address related CO h Global Source address related means that the bytes which follow represent a security level which is used in a security system This security system is established by the facility which assigned the source address The same applies to destination address related A uniform global quality service is provided here Parameter length 1 Parameter value 110abcde B one byte a 1 Routing decisions should take precedence over the delays of transmission instances i e all packets of a PDU must use the same route regardless of how long it takes 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 82 The Protocols of Layer 3 Minimum delay takes precedence Is always set to ze
26. are already available in layer 2 The control field of the I format PDU The l format PDU is used for data transmission I stands for Information This control field must be followed by data bytes N R and N S are cyclic numbers i e when 127 is reached counting starts again at zero MSB 15 14 13 12 11 10 9 8 7 6 5 4 3 2 LSB N R P F N S u N R Receive Sequence No N S Send Sequence No PF Poll Final Bit Fig 37 l format PDU The control field of the S format PDU The S format PDU is used to control data communication The control field of the RR PDU Data bytes are not permitted in this PDU Itis used to confirm received l format PDUs N R specifies which sequence number the receiver expects next All packets up to N R 1 are confirmed MSB 15 14 13 12 11 10 9 8 7 6 5 4 3 2 LSB un Pro o o o 0 olo i Fig 38 RR control field 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 63 The control field of REJ PDU Data bytes are not permitted in this PDU This PDU is used to request I PDUs be sent again starting at N R The PDUs up to N R 1 are confirmed If these PDUs occur frequently the transmission path is probably malfunctioning MSB 15 14 13 12 11 10 9 8 7 6 5 4 3 2 LSB Fig 39 REJ control field The control field of the RNR PDU Data bytes are not permitted in this PDU
27. of 1500 bytes If this is the case the transport layer of the sending station segments the TPDUs into six partial TPDUs and sends these to the Ethernet sender The receiver waits until all six TPDUs have been received before transferring them to the file server The individual TPDUs are sent over the network in succession O Splitting and recombination This procedure is comparable to segmentation except that the individual TPDUs are sent in parallel over several networks and not in succession This provides greater elasticity against errors and improves data throughput 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 88 The Protocols of Layer 4 4 4 2 The Transport Layer in Accordance with ISO 8073 4 4 2 1 The Individual Transport Classes Transport services of various classes are available depending on the network and LLC layer and their services below the transport layer If for example a class 2 LLC connection is being used flow monitoring i e measures intended to prevent a receiver from overflowing or duplicated data records from being transferred to the next instance is already provided by layer 2 thus relieving the transport connection of this task Three types of subordinate layers have been defined A Network layer transport layer connection with an acceptable residual error rate and acceptable rate of indicated errors This would mean that the lower layers hav
28. of the receiver This specification is based on a TPDU size of 128 bytes This parameter cannot be used for class O connections Parameter Code INAT NetSpector notation tra_delay Parameter Length 8 Bytes 0000 Parameter Values Bytes 3 and 4 Bytes 5 and6 Bytes 7 and 8 1099 002 Fax 49 911 5 44 27 27 e BE 49911 5 4427 0 Bytes 1 and 2 10001000 88 h 1000 Destination time sending and receiving station Highest acceptable time S E Destination time E S Highest acceptable time E E e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 98 The Protocols of Layer 4 m Reassignment time The reassignment time is the number of seconds during which the CR sending station attempts to reestablish the connection following the failure of the transport connection This parameter is only used for class 1 and class 3 connections Parameter Code 10001011 8B h INAT NetSpector notation reassign Parameter Length 2 Bytes 00000010 Parameter Value n 1 FFFFh Seconds Connection confirm CC This TPDU is sent back by the CR receiving station The variable portion must contain the same parameters as the variable portion of the CR TPDU Receipt of this TPDU means that the transport connection has been established and data transfer can begin As before an eventual data portion should not contain more than 32 bytes li_4 Length indicator Layer 4 TPDU Code CDT Credit dst_ref Destination R
29. true several stations are addressed simultaneously by one station The four octet checksum is sent atthe end of the packet During sending the sending station uses a certain algorithm to calculate the data for the checksum from the data stream and append these data to the data stream During receiving the receiving station also uses the same algorithm to calculate the checksum If atthe end of a packet both checksums are identical there is a very high probability that the packet has arrived at the receiving station without errors An error does not cause a direct reaction of layer 2a in the direction of the sending station A request for repetition would be conceivable Layer 2 also supplies the receiver with information on the physical length of the user data in octets As already mentioned the CSMA CD protocol requires that the packets have a certain minimum length calculated from the signal run time and the maximum network length However the actual user data may be as short as desired The unused remainder is filled with padding bits which contain no relevant information The length indicator is used to distinguish between user information and the padding bits When protocols which are not based on IEEE 802 3 are involved these two octets must be interpreted as the type field i e they provide no information on the actual length of the user data The elements of layer 2 provides answers to the following questions e Where is the packe
30. under menu item Switch Filters Off If the stations which you want to watch are located in a large network the capture buffer will be filled with irrelevant frames Filters must be enabled if you only want to capture certain information or frames The following chapter describes how to handle these filters Attention If you enable filters the fewer frames are captured or displayed 3 6 2 Working with Capture Filters The capture filters are selected with the menu item Capture Filter in the Tools menu Fewer frames are captured when filters are enabled The following dialog appears Capture Filter Ed VW Stations Only the Selected ais All but not the Selected Edit Cancel Filters effect on Qutgoing Frames Help Incoming Frames C Incoming and Outgoing Frames i EE Only the Selected Edit Allbut not the Selected Edit IV Multicasts Edit Only the Selected All but not the Selected Edit V Broadcast Fig 8 Dialog for the capture filters You can select the following settings Stations You have two choices O Only the Selected You specify all stations which you want included in the capture 1099 002 Fax 49 911 5 44 27 27 e B 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 36 Capture Filter O All but not the Selected You specify all stations whose frames you do not want incl
31. 1 Dialog for capture filters for frame types The Selected list contains the already entered frame types which were specified in the left hand field and added with the Add button If you want to remove an entry from the Selected list select the entry and click the Remove button Known types of frames Hex Identifier Designation FEFE SINEC H1 Intel FFFF IPX Novell Netware FOFO Netbeui Microsoft F1F0 NetBIOS IBM 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 38 Capture Filter Multicasts Multicasts are frames which are sent by single stations only to selected network stations Two lists are available O Only the selected Using the Edit button you can access a dialog with which you can specify all multicasts which you would like to capture O All but not the Selected Using the Edit button you can access a dialog with which you can specify all multicasts which you do not want to capture The following dialog appears for both selections after the Edit button is clicked Capture FilterMulticasts x Capturing only the selected ones didi Cancel New Selected ma 2 5 Hep 12 Remove lt lt Fig 12 Dialog for the multicast capture filters The Selected list contains the already entered multicasts which were entered in the New field and added with the A
32. 1 is not concerned with how bits are grouped into larger units or what these units mean In case of errors only the failure of the medium can usually be determined e g no signal plug not connected line interrupted or short circuited and so on Layer 1 is the only layer without addressing The following parameters are conceivable Transmission medium e Coaxial cable e Twisted pair e Optical fiber e Carrier frequency medium Encoding e NRZ non return to zero e Manchester e Parallel data IEC bus Connection technique e Plug connectors e Connections Data transmission speed e Bit sec e Byte sec Signal level e Current e Voltage e Rise and fall time of the signal e Input and output impedance Access procedures e Token e Polling e CSMA CD 1099 002 Fax 49 911 544 27 27 e 49911 54427 0 e D 90482 N rnberg e Ostendstra e 115 e INAT GmbH 54 The Protocols of Layer 1 Layer 1 errors can be best located and corrected with the following devices Level meters and reflector meters Carrier frequency measuring instruments Optical fiber measuring instruments Oscilloscopes Logic analyzers In contrast the INAT NetSpector serves no useful purpose until decoded data bits are available for evaluation These bits are provided with a clock pulse which indicates that the bit queued on the data line is valid Eight bits are combined into one octet These octets are the smallest units for decoding the higher proto
33. 11 5 44 27 27 e BB 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 112 The Protocols of Layer 4 Fixed portion li_4 Length of the Layer 4 Headers in Bytes the li_4 Bytes exclusively TPDU Code 0010 2 h dst_ref Insert here the src_ref of the remote station YR TU Nr Shows the next expected ED TPDU No The number is used for flow control Just in the expanded format each YR TU number should appear only once during a trouble free transmission that means repeats are not necessary Variable portion Checksum The checksum is calculated from all elements of the TPDU and consists of one record of two modulo 255 sums Parameter Code 11000011 C3 h INAT NetSpector notation Checksum Parameter Length 2 Bytes 0000010 Parameter Value 2 Bytes Checksum Reject RJ This TPDU is only used for classes 1 and 3 If a TPDU is lost during transmission the YR TU no is specified in RJU TPDU stating the starting point from which the transmission must be repeated For example receipt of the TPDUs with the numbers 1 2 5 and 6 means that the TPDUs with the numbers 3 and 4 have been lost The receiver sends an RJ TPDU with the number 3 i e the next TPDU number expected The sender must then repeat all TPDUs with numbers greater than 2 li_4 Length Indicator Layer 4 1 TPDU Code Credit 2 dst_ref Destination Reference 3 Header dst_ref Destination Reference 4 YR TU No 5
34. 111 N ED TPDU 106 ER TPDU 114 NetSpector window 9 Error 114 Error report PDU 84 O Expedited data 106 Expedited data acknowledgment 111 Optional settings 39 F P frame colours 43 Performance features 12 FRMR PDU control field 65 Printout 50 Printout in file 51 Program start 23 28 1099 002 Fax 49 911 5 44 27 27 ee 49911 544 27 0 D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 120 Index Protocols of layer 1 53 Protocols of layer 3 68 Protocols of layer 4 86 R Recording filters 35 REJ PDU control field 63 Repeater 69 RJ 112 RJ TPDU 112 RNR PDU control field 63 RR PDU control field 62 S SABME PDU control field 64 S format PDU control field 62 Source routing 72 Stations 35 Statistics 33 Supported protocols 12 System prerequisites 13 T Telegram list 41 Telegram types 37 Test PDU control field 61 Transport layer in acc w ISO 8073 88 Type 1 XID TPDU control field 61 Type 1PDUs control field 60 Type 2 PDU control field 62 Type 2 XID PDU control field 66 U UA PDU control field 64 U format PDU control field 60 63 W What INAT NetSpector gives you 11 What you can select 12 Working with filters 35 Working without filters 35 1099 002 INAT GmbH e Ostendstra e 115 D 90482 N rnberg T 49911 54427 0 e Fax 49 911 544 27 27
35. 3 2 Address Portion The address portion consists of a number of bytes which is not fixed A length indicator specifies how many bytes an address is to contain The length of the address is usually six bytes as with the MAC layer since the same addresses are used and these addresses are unique throughout the entire network 1st byte of the address portion or 10th byte of the header Designation da_li The destination address length indicator specifies the length in bytes of the destination address which follows This value is usually six 2nd byte of the address portion or 11th byte of the header up to m 1 th byte of the address portion Designation net_destination Specification of the network destination address in accordance with ISO 8348 AD2 where a hierarchical address management is defined see also ISO 8348 AD2 The address consists of three subgroups 1st group AFI Authority and format identifier i e specification of the network administrator 2nd group IDI Initial domain identifier i e which network is addressed 3rd group DSP Domain specific part i e which station is addressed ISO 8348 permits a maximum address length of 20 bytes mth byte of the address portion Designation sa_li The source address length indicator specifies the length in bytes of the source address which follows The value is usually six m 1 th byte to nth byte of the address portion Designation net_source Rules for this address ar
36. 55 sums Parameter Code 11000011 C3 h INAT NetSpector notation Checksum Parameter Length 2 Bytes 0000010 Parameter Value 2 Bytes Checksum 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 108 The Protocols of Layer 4 Data acknowledgment AK This TPDU is used for flow monitoring The receiving station uses this TPDU to confirm correct receipt of one or more depending on the credit data TPDUs 8 1 li_4 Length Indicator Layer 4 i TPDU Code Credit 2 dst_ref Destination Reference 3 dst_ref Destination Reference 4 m Header YR TU No 5 Variable Portion 6 li_4 6 Fig 72 AK TPDU normal format for classes 1 2 3 and 4 8 1 1 li_4 Length Indicator Layer 4 TPDU Code 0 0 0 0 2 dst_ref Destination Reference 3 dst_ref Destination Reference 4 YR TU No Bits 25 32 5 YR TU No Bits 17 24 6 I Header YR TU No Bits 9 16 7 YR TU No Bits 1 8 8 Credit Bit 9 16 9 Credit Bit 1 8 10 Variable Portion 11 li_4 11 Fig 73 AK TPDU expanded format for classes 2 3 and 4 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 109 Fixed portion li_4 Length of the Layer 4 Headers in Bytes the li_4 Bytes exclusively TPDU Code 0110 6 h dst_ref Insert here the src_ref o
37. A PDU UA stands for unnumbered acknowledge This PDU is used to confirm SABME and DISC PDUs The F bit should always be set MSB LSB 0 1 0 1 0 0 171 Fig 43 The UA control field 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 65 The control field of the DM PDU DM stands for disconnect mode This PDU indicates that the addressed LLC is not ready to receive data at the moment The F bit should always be set MSB LSB Fig 44 The DM control field The control field of the FRMR PDU FRMR stands for frame reject response This PDU is used by an LLC when errors which cannot be remedied by resending must be corrected The possible results are listed below e Receipt of an invalid or unexpected PDU e Receipt of an PDU whose information field is too long e Receipt of an invalid implausible N R e Receipt of an invalid implausible N S Bytes 1 to 5 are required for additional information For details see the description in the standard MSB LSB 1 0 O 1 0 1 1 1 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Fig 45 The FRMR control field 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 66 The Protocols of Layer 2 The control field of the typ 2 XID PDU The XID information field contains three pieces of information
38. AT GmbH 118 Abk rzungsverzeichnis M MAC Media Access MS More Segments MSB Most Significant Bit N O NRZ Non Return to Zero P Q PDU Protocol Data Unit R R E J Reject RNR Receiver Not Ready RR Receive Ready S SA Source Address SABME Set Asynchronous Balanced Mode Extended SAP Service Access Point SFD Start Frame Delimiter SP Segmentation Permitted T TOP Technical and Office Protocols TPDU Transport Data Control Units TSAP Transport Service Access Point U V UA Unnumbered Acknowledge UI Unnumbered Information W WAN Wide Area Network X Y Z XID Exchange Identification XNS Xerox Network System 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg Z 49911 54427 0 e Fax 49911 5 44 27 27 Index 119 7 Index A G AK TPDU 108 Gateway 74 Analyzing the recording 41 H B Hl connections 46 48 49 Bridge 70 Hl indication filter 46 48 49 Broadcast 38 How the INAT NetSpector works 9 C I CC TPDU 98 I format PDU control field 62 Connection confirm 98 Indication filters 41 Connection request 91 CR TPDU 91 K D Keyboard assignment 52 Data 104 L Data acknowledgment 108 DC TPDU 103 Layer 2 protocols 55 Disconnect confirm 103 Layout of layer 3 PDU 75 Disconnect request 100 LLC layer 57 DISC PDU control field 64 DM PDU control field 65 DR TPDU 100 M DT TPDU 104 MAC layer 56 Multicast 38 E EA TPDU
39. B 64 00 00 00 BI B5 D4 I 16 89 00 05 00 FF 00 00 00 FF 00 00 00 FF 00 tL Frames 2493 Bytes 246681 24 Lost 0 of ZA Fig 1 NetSpector overview Since the network card is connected to the local network all frames access the network card The frames are transferred to the NespDev driver via the installed card driver The capture filters now become active and transfer only the desired frames to the INAT NetSpector program where they are stored in a ring buffer or a linear buffer While being transferred to the buffer the sender and receiver of a frame are analyzed and a station list is prepared Using the left mouse button or the space bar of the keyboard you can select the stations from the station list whose frames are to appear in the frame list The frame list can be created after frame capture has been halted The display filters now become active Additional filters which can be selected via the options of the individual protocols also become active 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 10 What INAT NetSpector Gives You The frame list shows the frames in the order in which they occurred Using the PgUp PgDn keys or the arrow keys or the mouse you can page through the list to analyze completeness of the transmission or the time frame and transactions of the stations The frame located under the selection bar of the frame list is shown in the frame detail a
40. F 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF 00 00 00 FF Fig 22 Suppression of Header information TCP IP settings in the Frame detail In the Frame Detail window of Figure 21 the TCP and UDP Header information is suppressed for a more detailed analysis of the INAT Header 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 49 3 8 8 TCP IP Display Filter The dialog box TCP IP Display Filter controls the display of the TCP IP frames of the window Frame List TCP IP Display Filter Eg Choosing a selection results that the Telegrams are suppressed m Protocol Filter Cancel gessssssnssueg _ M UDP M ARP M ICMP m Telegram Filter I Syn I TCP Data I Fin Tl INAT Data Reset I INAT Life Data Acks T pure ACKs m Port Filter Filter Off C Only the Selected All but not the Selected New Selected Add gt gt Remove lt lt Port Info Fig 23 Suppression of TCP IP frames Frame List Protocol Filter Activating the button TCP UDP ARP or ICMP the corresponding frame is not displayed in the Frame List window Telegram Filter You are also able to
41. Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 40 Settings and Options 3 7 2 Capture Options The following dialog appears under the menu item Capture Options in the Tools menu Capture x Buffer en M Bing Size MB fi Default Cancel Help Network Adapter Clear Capture Fig 14 Dialog for setting the capture options Here you can set the capture buffer Capture must have been halted and deleted beforehand Buffer If the Ring option is selected frames are captured until capture is stopped When the buffer is full capture continues according to the ring principle i e the oldest frames are overwritten If the Ring option is not selected capture stops when the capture buffer is full All frames captured at the beginning remain in the buffer The Size of the capture buffer can also be set as an option The value can changed in 1 MB increments The default size is 1 MB Very large amounts of data can be captured If the capture buffer exceeds free RAM capacity portions are relocated to hard disk i e sufficient hard disk capacity must be available Since a long frame list requires a large amount of memory space and a long time to set up the size of the capture buffer should be kept as small as possible Network card If several network cards are mounted and their drivers are installed several networks can be mon
42. GmbH ANT T industrin Networks for Automation Technology User s Guide INAT NetSpector Network Analyzer Diagnostic and Monitoring Tool for Computer Networks Version 2 Manual version 1099 002 The contents of this manual and the related NetSpector Software are the property of W Mehrbrodt INAT GmbH This material is subject to the conditions of a general or special license contract one time license and may only be used or reproduced when the terms of agreement as set forth in this contract are fulfilled The specifications in these documents are provided without responsibility for errors or omissions The contents are subject to change without prior notice The contents are subject to change due to technical advance Copyright INAT GmbH 1998 Industrial Networks for Automation Technology Ostendstrasse 115 D 90482 N rnberg Z 49 911 544 27 0 Fax 49 911 5 44 27 27 BBS 49 911 5 44 27 28 E Mail Info inat de Internet www inat de If information was received too late to be included in this manual you will find this information in a file on the installation diskette included To read this information if present place INAT driver diskette 1 in drive A and make the following entry in the input line TYPE README TXT To view the file use the NNOTEPAD text editor under Windows NT or Windows 95 text editor E or EPM for OS 2 or another text editor All rights reserved Author W Mehrbro
43. ISO Communication Protocols 69 4 3 2 Notes on the Connection of Local Networks The store and forward principle is used for all network transitions i e data elements which are to leave the LAN are completely stored on the interface before being forwarded The meaning of data element varies from transition to transition A repeater implements the store and forward principle at the bit level while a bridge or gateway or router implements this principle at the packet level These three transition components will now be explained 4 3 2 1 The Repeater The repeater is the simplest way to connect LAN subnetworks It functions at a purely physical level It implements the store and forward principle at the bit level i e each bit which arrives is forwarded one to one in both directions Repeaters are used when a LAN area is too large or when aLAN must be segmented because there are a very large number of stations Since the repeater performs purely physical routing the connected LANs must also precisely adhere to the physical specifications particularly concerning the run time conditions of CSMA CD networks The total signal run time from one end of the total network to the other may not exceed one half of one slot time It is obvious that layer 3 does not have to be used for LANs equipped with repeaters x L S2 S4 Repeater Repeater Segment 1 Segment 2 Fig
44. T NetSpector This chapter provides general information on the INAT NetSpector The menu items in the program are explained and you are shown how to capture frames and analyze them Filters can be used for capture and analyzing frames Among other topics this chapter describes how to use the various filters Description of the ISO Communication Protocols This chapter offers a detailed description of the ISO communication protocols including the layout of the protocols of layers 1 to 4 of the ISO 7 layer model 1099 002 Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Contents TABLE OF CONTENTS 1 HOW THE INAT NETSPECTOR WORKS 1 1 What INAT NetSpector Gives You 1 2 Supported Protocols 1 3 What You Can Select 1 4 System Prerequisites 2 INSTALLATION AND PROGRAM START 2 1 Hardware Installation 2 1 1 Installation on the Parallel Interface 2 1 2 Installation on the Serial Interface 2 1 3 Technical Data of Hardlock II 2 2 Software Installation 2 2 1 Installation under Windows NT and Windows 95 2 2 1 1 Installation of the Program under Windows NT and Windows 95 2 2 1 2 Installation of the hardlock driver by hand 2 2 1 3 Starting the Program under Windows NT and Windows 95 2 2 2 Installation under OS 2 2 2 2 1 Installation of the Program under OS 2 2 2 2 2 Starting the Program under OS 2 3 WORKING WITH INAT NETSPECTOR 3 1 Capture Frames 3 1 1 New Capture 3 1 2 Stopping the Capture 3 1
45. The user related side of the total architecture and the transmission related side are separated here Since the protocols have end to end characters e g similar to telephones they represent the primary link guaranteeing correct data communication between users The transport layer corrects errors establishes and disconnects connections and monitors correct data flow Since each process and each application can be programmed to directly build on layer 4 it is ensured that the process will be able to work with correct data The transport layer ensures that all data transferred by it to higher layers are complete unduplicated and have no errors caused by the transmission path Generally speaking the following service categories may conceivably be used to describe a transport service 1 Transport type Connection oriented or non connection datagram service Only the connection oriented service is described in the ISO standard 2 Quality of the transport service Acceptable degree of errors and data loss Expected average and maximum delay Expected average and minimum data throughput and high reliability to prevent repetitions at the file level since this would be particularly time consuming 3 Data transmission The basic task of a transport service is to transmit user and monitoring data 4 User interface The user interface to the transport service 5 Connection management The correct establishment or disconnection of a connection
46. a SAP 12 with process 2 on station 3 via SAP 31 and so on Although the same physical stations are involved the two services are logically completely separate from each other Thus one physical connection can theoretically handle up to 128 logical connections SAPs are logical addresses Multiplexing in this case means that a connection is established in the LLC layer between station 1 and station 3 for example and SAP 11 communicates with SAP 31 at the same time as SAP 12 communicates with SAP 32 SAP11 SAP12 SAP13 SAP21 SAP22 SAP31 SAP31 Fig 32 Equivalent of the arrangement shown above This example also applies to higher layer SAPs A communication connection itself must no longer have anything to do with the physical connection 1099 002 Fax 49 911 5 44 27 27 e BB 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 60 The Protocols of Layer 2 4 2 3 2 The Control Field in Type 1 PDUs MSB LSB 2 M Defines the package type PDU Type M M M PF M M 1 1 P F Pol Bit Command LLC PDU Final Bit Response LLC PDU Fig 33 General presentation of the control field The control field of the U format PDU MSB LSB Fig 34 The UI control field UI stands for Unnumbered Information Data bytes always follow This PDU is used for the data transfer The P F bit should always be zero If not this must be interpreted as a protocol error The C R bit in SSAP must always be 1 The LLC layer does n
47. a generous selection of hotkeys since the primary functions are assigned to function keys i e fast access The tool bar can also be used for easy control Reliable information on all activities currently running on the network History recording of network activity over a certain period of time Online display of all communicating stations with names assigned to station numbers Overview of which stations are communicating and how much data is being exchanged You view the frames of a capture in a well organized list with short descriptions The individual frames can then be viewed decoded in detail into plain text hex and ASCII formats Color identification of the various types of frames Display and printout of station lists and frames with various levels of information Individual settings permitting frame analysis with varying degrees of detail exist for the available protocols Storage of the user profiles Recording depth up to 99 MB i e approx 1 million H1 frames High resolution time base of 10 usec INAT NetSpector can be provided with various protocols Decoding of the SINEC H1 protocol and TCP IP is already included Single frames are interpreted in detail Easy to install While the INAT NetSpector is recording network communication you can use your computer for other applications Extensive context sensitive help Easy to expand with other network protocols 1099 002 Fax 49 911 5 44 27 27 e BB 49911 54427 0 e
48. above The LLC layer must be type 1 IEEE 802 2 All data of the header portion are assembled by the sending station Segmentation is not performed by the sending station since this is done by the gateway if necessary Reassembly is performed by the receiving station The gateway reads the routing from the address portion of the PDU MAC Part LLC Part Layer 3 PDU Fig 53 Location of the layer 3 PDU complete packet 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 5 A layer 3 PDU has the following layout Fixed portion Address portion Layer 3 Header maximal lengtr 254 Bytes Segmentation portion Optional portion Data portion Layer 4 and gt Fig 54 The layer 3 PDU The fixed portion contains information on whether layer 3 exists the length of the PDU header the ISO 8473 version supported the length of time the PDU has been on the network and the length of the packet The checksum provides additional protection of the entire header against distortion This checksum is also located in the free portion of the PDU The address portion contains the station address of the source and destination station Throughout the entire network each station should have a unique address After segmentation by the gateway the segmentation portion handles the correct designation of the indi
49. al format for classes 1 and 3 113 Fig 77 RJ TPDU expanded format for class 3 114 Fig 78 ER TPDU for classes 1 and 3 115 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg T 49 911 544 27 0 Fax 49 911 5 44 27 27 List of Abbreviations 117 6 List of Abbreviations A B ABM Asynchronous Balanced Mode AFI Authority and Format Identifier specification of the network administrator AK Data Acknowledgment AP Application Protocol C CC Connection Confirm CCITT Consultative Committee for International Telegraphy and Telephony CR Connection Request CRC Cyclic Redundancy Check CSMA CD Carrier Sense Multiple Access with Collision Detect D DA Destination Address DC Disconnect Confirm DISC Disconnect DLC Data Link Control DM Disconnect Mode DR Disconnect Request DSP Domain Specific Part i e which station is addressed DT Data E EA Expedited Data Acknowledgment ED Expedited Data ER Error Report F FCS Frame Check Sequence FRMR Frame Reject Response G H HDLC High Level Data Link Control I J K Information ID Identifier IDI Initial Domain Identifier i e which network is addressed IEEE Institute of Electrical and Electronic Engineers ISO International Organization for Standardization L LAN Local Area Network LI Length Indicator LLC Logical Link LSB Least Significant Bit 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e Ostendstra e 115 e IN
50. al interface it can only be activated by the Hardlock configuration variable 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 16 Hardware Installation The syntax of the configuration variable is shown below HL_SEARCH Port Port consists of the I O address in hexadecimal and a port identifier Example SET HL_SEARCH 378p 2f8s Hardlock is only searched for with address 0x378 on the parallel interface and 0x2f8 on the serial interface The following table lists the port identifier p parallel Normal parallel port s serial Normal serial port e ECP Parallel port in ECP mode n NEC Japan Since Japanese models have a different port assignment this parameter can be used to activate special handling A separate NEC API is not required C Compaq Contura Dockingbase The multiplexer of the docking base for switching between parallel port and Ethernet adapter is reset to the parallel port for the Hardlock scan i IBM PS 2 Specification for IBM PS 2 corrects an error during port reprogramming of certain video drivers under Windows i e Hardlock could no longer be found after Windows was started This had always been performed internally by the Hardlock API It can now only be activated by specifying the configuration variables As shown in the example above the configuration variable is set under Windows NT in the menu Control panel System Environme
51. alyser folder located in the work area 2 Inan OS 2 total screen or an OS 2 window enter the following command NETSPECT The program is started Open the following folders on your work area OS 2 System and then drives Open the folder of the drive on which you installed NetSpector Then open the NetSpector folder There are now several ways to proceed 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 3 49911 54427 0 e Fax 49 911 544 27 27 Working with INAT NetSpector 29 3 Working with INAT NetSpector Basically the INAT NetSpector network analyzer involves two stages e Capture frame communication e Analyzing a capture Filters and display options are set to obtain a clear and uncluttered view of the data 3 1 Capture Frames 3 1 1 New Capture When the INAT NetSpector program starts capture is started immediately The frames from the network card are placed in the capture buffer if the network card is connected to an intact network Active capturing is indicated by the red background of the Statistics window All stations which are currently communicating with the network are indicated in the station list You can also obtain a new capture of the frames by selecting the menu item New Capture in the File menu This deletes the previous contents of the station list 3 1 2 Stopping the Capture Capture is halted with the menu item Stop Capture in the Edit menu The captur
52. are see 109 receipts Data Data Frames see 105 Ex Data Expedited Data see 107 Error Error Frames see 115 Error Response Confirmation of see 84 Error Frames RJ Reject siehe 113 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 47 Options SINEC AP data in the frame detail window When this option is selected the Siemens AP i e Application Protocol header of the H1 frames is indicated decoded Connection filter The individual H1 connections between the stations are shown in the H1 Connections window S NetSpector H1 Connections iB File Edit View Tools Window Help laj xj Dlelals x alas ASE B T Own Address Dest Address Dest TSAP 5 TCP IP 2 S5 TCPAP 2 Leitrechner 5 TCPIP 2 Leitrechner 5 TCPJIP 1 5 TCP IP 2 lt PCPCPCPC gt lt SPS_READ gt Leitrechner 55 TCPAP 2 lt PCPCPCPC gt lt SPSWRITE gt Leitrechner 55 TCPAP 2 lt FAH1 gt lt FPH1 gt 55 TCPAP 1 F1 for help NUM Fig 20 H1 connections Entries can be selected similar to the station list The H1 Display Filter dialog in the Connection Filter area can then be used to specify whether only the specified connections are to be indicated or whether all connections except those specified are to be indicated or whether the markings in the window are to be disregarded 1099 002 Fax 49 911 544 27 27 e 49911 54427 0 e D 90482 N rn
53. be forbidden altogether The Internet protocol i e IP also uses Lifetime for PDUs while XNS and DECNET work with hop counts 5th byte Designation Flags or type MSB LSB FELET Flags Type Fig 55 Byte 5 SP Segmentation permitted MS More segments ER Error report Flags 1xx Segmentation permitted Flags 11x More segments i e this segment is not the last segment of a datagram This constellation can only be used when segmentation is permitted Flags xx1 Error report desired An error report PDU must be sent to the sender when a datagram has to be rejected Type 11100 1C h Data PDU Type 00001 01 h Error PDU 6th and 7th bytes Designation segment_length This value contains the total length i e header plus data of the segment Byte 6 is the more significant byte and byte 7 is the less significant byte 8th and 9th bytes Designation net_checksum A checksum is generated for the entire header A checksum of zero can be ignored A checksum other than zero must be calculated by the receiver and compared with the checksum received If the two checksums are not identical the PDU must be rejected When Lifetime changes the checksum also changes See annex C of ISO standard 8473 for the algorithm to be used for calculating the checksum 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 78 The Protocols of Layer 3 4 3
54. berg e OstendstraBe 115 e INAT GmbH 48 Analyzing the Capture 3 8 7 TCP IP Settings The dialog box TCP IP settings and the window Frame detail are available for more detailed analysis of data communication between two Ethernet stations communicating via the TCP IP protocol Activating the button IP Header TCP Header or UDP Header the corresponding Header display in the Frame Detail window is suppressed The suppression becomes active when a new frame is displayed in the Frame Detail window TCP IP Settings in the Frame Detail Ed Suppress Header Choosing a selection results that the Header Informations are suppressed Cancel M IP Header DE NAT Header IV TCP Header Sinec AP Header Help IV UDP Header Eoma N decimal Ei fe byte wise fe hevadecimal C Wwordnise Intel G Wword wise Motorola Fig 21 Suppression of Header information TCP IP settings in the Frame detail Gj Frame Detail No 199 Time 0 02800 Own S5 TCP IP 1 Dest S5 TCP IP2 Bytes 162 ype IP from 195 180 213 173 to 195 180 213 172 TCP 5 400 D 4525 CMD lt ACK gt lt PSH gt lt 108 bytes gt DLC DLC Header DLC Frame size 162 A2 hex DLC Destination Station 55 TCP IP 2 DLC Source Station 55 TCPAP 1 DLC INAT Industrial Networks Header INAT 100 bytes of data Flags Od Oh Seq 46514 Non Blocked Data D4 B1 16 89 00 05 00 FF 00 00 00 FF 00 00 00 F
55. boxes they are shown as bytes words and so on Their significance is inverted and adapted to the mathematical formulation for hex binary or decimal numbers In this type of formulation the LSB i e Least Significant Bit is located to the far right The octet representation shown above indicates the sequence in which the data appear on the network This type of representation conforms to explanations used in the standards The bit to the far left is not sent until time t 0 MSB LSB MSB LSB D D D D D D OD IG S S S S S S S CR DSAP SSAP Fig 30 Addresses of the LLC layer in bytes The meaning of the individual bits is shown below In DSAP In SSAP G 0 Individual DSAP C R 0 Command G 1 Group DSAP C R 1 Response SAP xxxxxx0x Individual addresses SAP xxxxxx1x Reserved for 802 definitions SAP 11111111 FFh Global SAP SAP 0000001x SAP for layer management SAP 0000000x Zero address only connection to the MAC layer no connection to higher layers 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 59 The following example shows how SAPs are used Process Process Process A A Station 1 Station 2 Station 3 Fig 31 SAPs in various stations For example process 1 on station 1 can communicate via SAP 11 with process 2 on station 3 via SAP 32 Process 2 on station 1 can communicate vi
56. col layers i e also for the INAT NetSpector NRZ Raw data Octet Ratex gt Decoder Clock Serial Parallel converter Rate x 8 Fig 26 Principal data conditioning for the INAT NetSpector 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 55 4 2 The Protocols of Layer 2 4 2 1 General Layer 2 converts an unreliable transmission channel into a reliable one It converts a stream of raw data bits into a packet to which a security checksum is added The packet is not sentto a higher layer unless this checksum is correct This layer is often referred to as the DLC layer i e Data Link Control layer It ensures a reliable connection between network connections It offers both datagram services and connection oriented services Where datagram services are concerned the data of the higher layers are usually combined into several packets and transmitted from sender to receiver without further flow monitoring by layer 2 Monitoring and arrangement of the packets are left to the higher layers Where connection oriented services are concerned a virtual connection between both communication partners is established and then the data which have been combined into packets are transferred with layer 2 flow monitoring i e layer 2 ensures that all packets transmitted from sender to receiver arrive in error free condit
57. dd button An entry can be removed again by double clicking or selecting an entry and clicking the Remove button Broadcast Broadcasts are frames which are sent by single stations to all network stations Example A server sends the time cyclically If this field is selected no broadcast frames will be included in the capture buffer 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Working with INAT NetSpector 39 3 7 Settings and Options 3 7 1 Setting Noise and Time Display The following dialog appears under menu item Settings in the Tools menu Settings x Capture Cancel m Time Display Help FRE Relative Difference C Absolute Fig 13 Dialog for settings Capture Here you can set whether the speaker is to generate a tone each time a frame is received This permits you to roughly estimate the network load even without using a monitor screen Time display If Absolute time display is selected the absolute time of arrival of the captured frames is displayed in the Frame List and Frame Detail window Absolute time means the system time of the computer on which the NetSpector software is installed If you activate the Relative Difference button the relative time of arrival of the captured frames referring to the preceding frame is displayed in the Frame list and Frame Detail window 1099 002
58. dt 49 2261 979 544 SIMATIC is a registered trademark of Siemens AG STEP 5is a registered trademark of Siemens AG os 2 Warp is a registered trademark of the IBM Corp Windows95 is a registered trademark of the Microsoft Corp Windows NT is a registered trademark of the Microsoft Corp IBM LAN Server are registered trademarks of the IBM Corp 3Com is a registered trademark of the 3Com Corp EtherLink III is a registered trademark of the 3Com Corp 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 On this manual This manual describes the installation and use of the INAT NetSpector Numerous illustrations taken from the running program are used to explain the individual steps involved in using the INAT NetSpector One chapter describes the ISO communication protocols for layers 1 to 4 Overview Chapter 1 Chapter 2 Chapter 3 Chapter 4 INAT GmbH How the INAT NetSpector Works This chapter describes the performance features and options offered by the INAT NetSpector Also covered in this chapter are the system required for NetSpector operation and the principle on which the INAT NetSpector is designed Installation and Program Start This chapter provides guidelines on installing the INAT NetSpector It also covers installation under various operating systems and the different methods of starting the program Working with the INA
59. e A number of bytes with any content C5 h security one byte Designation Net_security This parameter requires a certain transmission security level from the transmission instances ISO 8348 ADD 1 suggests four levels 1 No protection 2 Protection against passive monitoring 3 Protection against modification repetition insertion and destruction of data 4 Items 2 and 3 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 81 ISO does not specify how the security level is to be encoded in the PDU header It only provides the possibility and differentiates between the individual transmission instances from which the security level coded in the header stems This prevents misinterpretations This differentiation byte is the first byte of the parameter value Further level coding is located in the value parameter and must be known to the participating instances along the transmission path Parameter length Variable one byte Parameter value Only the first byte is specified 00 h Reserved 40 h Source address related 80 h Destination address related CO h Global Source address related means that the bytes which follow represent a security level which is used in a security system This security system is established by the facility which assigned the source address The same applies to destination
60. e Capture Capture Frame List Filter Help Save Stop Previous Display Capture Capture Frame Filter Exit Fig 25 NetSpector tool bar 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 52 Keyboard Assignment 3 10 Keyboard Assignment The INAT NetSpector can be used with both the mouse and the keyboard Use of the INAT NetSpector requires a basic knowledge of window oriented user interfaces NetSpector uses the following keys Key Function F1 Help F3 Create frame list F4 Delete capture F6 Start capture F7 Stop capture Tab key Switch to next window When a dialog window is involved the input marker jumps to the next dialog element Shift Tab key Switches to the previous window When a dialog window is involved the input marker jumps to the previous dialog element Alt PgUp Jumps to the previous frame Alt PgDn Jumps to the next frame Space bar Selects or deselects an option Return key Same as the OK button ESC key Same as the Cancel button Alt F4 Exits the program 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 53 4 Description of the ISO Communication Protocols 4 1 The Protocols of Layer 1 The electrical physical and procedural parameters and aids for a physical connection are specified in layer 1 Layer
61. e Lifetime Before forwarding the packet a gateway collects all segments and reassembles the original packet and then transfers it to the sending waiting queue The sender of the gateway segments the packet again When Lifetime expires the packet is removed from the ring Time monitoring is also advantageous since it tells the gateway when a datagram can no longer be reassembled e g due to loss of single segments The gateway is then able to rid its receiving buffer of segments which have already arrived since arrival of the missing segments can no longer be expected 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 77 It is obvious to the observer of network communication that when the Lifetime of the received packet is still long this indicates high speed data communication Other protocols use the hop count to monitor the Lifetime Here only the number of gateways passed is counted Each gateway decrements this number A packet is removed from the network if it does not reach its destination by the time the hop count equals 0 The advantage of buffer cleanup provided when Lifetime mode is used does not exist here Segments of a packet which have already arrived at the gateway occupy buffer space and may not be deleted Other internal mechanisms must be used to regulate the Lifetime of such fragments in the buffer or segmentation must
62. e already prepared the data stream so that no errors related to transmission occur and thus no errors are reported to the transport layer B Network layer transport layer connection with an acceptable residual error rate and unacceptable rate of indicated errors This means that the network layer reports errors to the transport layer which it is unable to correct itself and which the transport layer must then correct However a large portion of the data security measures is handled by the network layer C Network layer transport layer connection with unacceptable residual error rate and unacceptable rate of indicated errors This means that the network layer forwards the data unchecked to the transport layer and leaves all error treatment to the transport layer This type is usually used by LANs i e the LLC layer is not user friendly and the network layer is primarily responsible for transporting the data over the various networks Correct logical data flow is handled by the transport layer Because of this organization five classes of transport have been defined in the ISO standard i e two each for type A and B and one for type C See table Class 0 Simple class This class was developed by CCITT for teletex Flow monitoring is handled by the LLC layer or by X 25 The following services are available e Connection establishment e Data transfer with segmentation e Error report The following services must be provided by the lowe
63. e is involved the station list is supplied with the current data on communicating stations The frame list the frame detail and the frame hex remain blank during the capture S NetSpector Station List File Edit View Tools Window Help Dejals x Blei ASE Bl Bl Own Address Dest Address Frames Bytes Leitrechner S5 TCPAP 2 657 39420 S5 TCPAP 2 Leitrechner 613 36780 Roboter 1 Roboter 2 155 39900 Roboter 2 Roboter 1 307 18424 55 TCPIP 1 s5 TCPAP 2 250 Leitrechner INAT 050013 Leitrechner Leitrechner FFFFFFFFFFFF F1 for help Fig 5 Station list Since each entry stands for frames of a certain transmission direction two stations which are communicating with each other cause two entries In addition to Own Address and Dest Address the number of Frames which have been sent and the number of Bytes which have been transferred are indicated If the capture buffer is in ring mode the number of frames and bytes does not match the number in the buffer Instead it represents the number of frames sent since the capture started This happens when the ring buffer is full and old frames have already been overwritten 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 33 3 3 Symbolic Station Names You can use the INAT NetSpector to assign symbolic names to the stations This makes it easy to identify stations in the network
64. e must be stopped for the following reasons e Generate the frame list e Save the capture e Print the capture e Change the settings of the capture buffer e Select another network card 3 1 3 Starting the Capture Capture is started with the menu item Start Capture in the Edit menu The contents of the capture buffer are deleted without an are you sure inquiry and a new capture is started The stations in the station list are retained Capture can also be started with the menu item New Capture in the File menu but the station list is deleted 3 1 4 Deleting the Capture The capture is deleted with the menu item Delete Capture in the Edit menu The capture buffer can be emptied at any point in time without an are you sure inquiry 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 30 Capture Frames 3 1 5 Saving the Capture The capture must be stopped before it can be saved to the hard disk The following dialog appears after tne menu item Save capture is selected from the File menu Save Capture Suchen in a NetSpect j c a NetSpect cap Dateiname MESEN Dateityp Capture Files cap 7 cee Fig 3 Dialog for saving the capture In the dialog for saving the capture you can select the drive the directory and the file name as desired The file extension is fixed i e cap This preven
65. e the same as those for net_destination 4 3 3 3 Segmentation Portion This portion directly follows the address portion Since the address length varies the exact byte positions cannot be specified The segmentation portion must exist when the SP flag is set in the fixed portion When a PDU is segmented by the network layer due to different maximum permissible packet lengths in the network the segmentation portion ensures that the PDU will be able to be reassembled correctly by the receiver The segmentation portion is always six bytes in length 1st and 2nd bytes of the segmentation portion Designation unit_id The data unit identifier specifies the starting PDU The segment offset in this PDU must always be zero 3rd and 4th bytes of the segmentation portion Designation seg_ off Segment_offset specifies the relative position of the data portion which follows to the starting position 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 79 Basic PDU Segmented PDUs segment_ Starting PDU length Offset 0 00 Offset 000 Header These three segments total_ Offset 200 are sended separately length Offset 200 and successively Their headers are equal Offset 400 Header Offset 400 Fig 56 Segmentation of a PDU 5th and 6th bytes of the segmentation portion Designation total_length In contra
66. e this class assumes that the services of the network layer and the layers below are unreliable the transport layer must provide repetition strategies detection of duplicates flow monitoring and recovery after total breakdowns i e all services which ensure that distorted data are not transferred to higher layers The following services are available e Allclass 0 to 3 services e Data security with checksums e Time monitoring i e repeated transfer after timeout and inactivity monitoring e Splitting and recombination The transport class is selected based on the subordinate layer on which the transport layer is built A class 1 LLC layer and a class 4 transport layer are usually used for LANs A combination of class 2 LLC layer and class 0 or 2 transport layer is also used for token ring networks 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 90 The Protocols of Layer 4 Protocol Mechanism Variant Assignment of the Network Connection TPDU Transmission Segmentation Comprise and Separate Establish Connection Reject Connection Status Display normal Implicit Explicit Status Display Error Assignment of TPDUs to Transport Connections DT TPDU Numbering Normal Extented Express Data Transfer Network Normal Network Expedited Reestablishment after Errors Repeat until Confirmation Conf Receipt of the TPDUs AK New Synchronization Multiplexing and Demultip
67. eference dst_ref Destination Reference src_ref Source Reference 5 t Header src_ref Source Reference 6 class 0 0 Option 7 Variable Portion 8 li_4 8 Fig 64 The CC_TPDU 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 99 Fixed portion li_4 Length of the layer 4 header in Bytes the li_4 Bytes exclusively TPDU_Code 1101 D h CDT Assignment of the original credit 0000 dst_ref Insert here the src_ref of the received CR_TPDU src_ref No of the connection which defines the establishing connection in the CC of the sending station class Notation of the Layer 4 class which supports the connection 0000 Class 0 0001 Class 1 0010 Class 2 0011 Class 3 0100 Class 4 Option format 0 normal format in all classes the TPD number as well as the confirmation numbers have a length of seven bits 1 extented format in the classes 2 3 4 the numbers have a length of 31 Bits flow_control O with flow control in class 2 1 without flow control in class 2 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 100 The Protocols of Layer 4 Disconnect request DR This TPDU is sent by the station which wants to disconnect the connection User data should not exceed 64 bytes 8 1
68. emove a station again from the Selected Stations list double click this entry or select this station and click the Remove button Filters effect on O Outgoing Frames Activating this selection you will access a dialog regarding only the Incoming Frames of a correspondent station which you would like to capture O Incoming Frames Activating this selection you will access a dialog regarding only the Outgoing Frames of a correspondent station which you would like to capture 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 37 O Incoming and Outgoing Frames Activating this selection the selected Filters effect on both Incoming and Outgoing Frames of a correspondent station which you would like to capture Frame types Two lists are available O Only the Selected Using the Edit button you can access a dialog with which you can specify all frame types which you would like to capture O All but not the Selected Using the Edit button you can access a dialog with which you can specify all frame types which you do not want to capture The following dialog appears for both selections after the Edit button is clicked Capture FilterT elegram Types Ea Capturing only the selected ones Cancel New Selected Fi Fd FEFE Help Add gt gt eit Remove lt lt Fig 1
69. end to LLC2 I N S 5 P 1 N R 4 Send to LLC1 RR F 1 N R 6 and so on P poll bit F final bit l format RR Receive Ready N sequential numbers 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 67 Sending machine A A may send seven frames 4 Ns 0 Ns 1 Ng 2 A ce Np 3 7 1 fo N ge z a N A shrinks its window with p Bier un each transmission 6 gt 2 A expands its window with each acknowledgement 7 mn 1 a A may now only send ft 4 three more frames f 6 2 SS Vv 3 5 ST 4 N sequence number of frame sent Np sequence number of next frame expected Shaded part designates window From Stallings data and computer communications Receiving machine B B is prepared to receive seven frames B acknowledges all three frames and adjusts its window B decides to limit the flow Fig 47 Sending l format PDUs with acknowledgment 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 68 The Protocols of Layer 3 4 3 The Protocols of Layer 3 4 3 1 General Layer 3 i e the network layer provides optimal data transport within a network which itself can be made up of many subnetworks Layer 3 offers the following services e Routing e Error detection e Se
70. eters Step 3 Copy the files from the floppy disk labeled NetSpector OS 2 Disk 2 2 from the directories DRIVER MACS DRIVER PROTOCOL DRIVER TOOLS and DRIVER VAR_A to hard disk C in the directory NESP_OS2 treiber MACS c nesp_os2 treiber PROTOCOL c nesp_os2 treiber TOOLS c nesp_os2 treiber VAR_A c nesp_os2 xcopy xcopy xcopy a a a xcopy a Step 4 Add the following entries to the CONFIG SYS files Addition to C CONFIG SYS device c NESP_OS2 protman OS2 i c DRV_OS2 DEVICE C NESP_OS2 ELNK3 0S2 device c NESP_OS2 NESPDEV OS2 RUN C NESP_OS2 NETBIND EXE Excerpt from PROTOCOL INI PROT_MAN DRIVERNAME PROTMANS IBMLXCFG ELNK3 nif ELNK3 nif NESPDEV_nif NETSPECT nif 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 28 Software Installation NESPDEV_nif DriverName NESPDEVS Bindings ELNK3_nif ELNK3_nif DriverName ELNK3S IOADDRESS 0X340 Step5 Perform a system shutdown Start your computer again and make sure that all programs are loaded without error messages when the system boots 2 2 2 2 Starting the Program under OS 2 There are several ways to start the program 1 Start the NetSpector Network Analyzer program by double clicking the NetSpector Network An
71. f Short Text is selected the entries are printed as a list The information is available from the Frame List window The printer should be set to condensed type since the printout has approximately 130 columns If the short text printout is not sufficient Long Text and or Hex Dump can also be printed Long Text is a detailed description from the protocol display Just how detailed this is depends on the settings of the appropriate protocol DLLs Before the printout the NetSpector DRA file is sent to the printer This permits the printer to be initialized with a certain printing sequence After the printout the NetSpector DRE file is sent to 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 51 the printer This permits the printer to be reset with a certain printing sequence Both files should be located in the same directory as NETSPECTOR EXE Print to File sends the output to a file At the start of the printout the file selection box is shown where the drive the path and file name can be specified If this option is not used output is made to the standard system printer i e prn 3 9 Tool Bar The most important functions can be triggered from the tool bar E NetSpector _IoJx File Edit View Tools Window Help pelaje x alee yole El R ew Print Delete Next N Captur Capture Frame Qpen Start Create Captur
72. f the remote station YR TU Nr Shows the next expected TPDU No The number is used for flow control Just in the expanded format each TPDU number should appear only once during a trouble free transmission that means repeats are not necessary Credit Shows the number of data TPDUs which can be sended without a confirmation See also CR credit mechanism Variable portion a Checksum The checksum is calculated from all elements of the TPDU and consists of one record of two modulo 255 sums Parameter Code 11000011 C3 h INAT NetSpector notation Checksum Parameter Length 2 Bytes 0000010 Parameter Value 2 Bytes Checksum b Subsequent number This parameter ensures that the acknowledge TPDUs are handled correctly when flow monitoring subordinate to layer 4 is used Parameter Code 10001010 8A h INAT NetSpector notation subseq_nr Parameter Length 2 Bytes 00000010 Parameter Value 16 Bit Sub sequence number 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 110 The Protocols of Layer 4 c Flow control confirmation A copy of the AK TPDU which was sent is sent back as confirmation to the station which sent an AK TPDU This permits the sender of the AK TPDU to check the status of the receiving terminal Parameter Code INAT NetSpector notation Parameter Length Parameter Value INAT GmbH OstendstraBe 115 10001100 8C h window
73. g 49 Connection of two LAN segments with repeaters 69 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e Ostendstra e 115 e INAT GmbH 116 Abbildungsverzeichnis Fig 50 Connection of two LANs with bridges 70 Fig 51 The backbone network 70 Fig 52 Sample network for source routing 72 Fig 53 Location of the layer 3 PDU complete packet 74 Fig 54 The layer 3 PDU 75 Fig 55 Byte 5 77 Fig 56 Segmentation of a PDU 79 Fig 57 Layout of the parameters 80 Fig 58 Parameter setup for source routing 83 Fig 59 The error report PDU 84 Fig 60 Functions of the ISO transport protocol classes 90 Fig 61 CR_TPDU 9 Fig 62 Example of a credit 93 Fig 63 Layout of the variable portion 94 Fig 64 The CC_TPDU 99 Fig 65 The DR_TPDU 101 Fig 66 The DC TPDU 104 Fig 67 DT_TPDU normal format for classes 0 and 1 105 Fig 68 DT_TPDU normal format for classes 2 3 and 4 105 Fig 69 DT TPDU expanded format for classes 2 3 and 4 106 Fig 70 ED TPDU normal format for classes 1 2 3 and 4 107 Fig 71 ED TPDU expanded format for classes 2 3 and 4 108 Fig 72 AK TPDU normal format for classes 1 2 3 and 4 109 Fig 73 AK TPDU expanded format for classes 2 3 and 4 109 Fig 74 EA TPDU normal format for classes 1 2 3 and 4 112 Fig 75 EA TPDU expanded format for classes 2 3 and 4 112 Fig 76 RJ TPDU norm
74. gmenting i e dividing a large packet into many small ones e Reassembling i e putting the large packet back together e Sorting of packets which got out of order during transmission The simple presentation below shows three subnetworks which are connected via gateways Think for example of the three office networks of a national bank with one network in Hamburg one in Berlin and one in Cologne Subnetwork 2 Subnetwork 1 Subnetwork 3 G Gateway S2 S Station Fig 48 Typical arrangement of several subnetworks in one total network When station 1 wants to send data to station 2 there are two possible paths e Path 1 From network 3 via G3 to network 1 and station 2 e Path 2 From network 3 via G2 over network 2 via G1 to network 1 and station 2 Either station 1 decides on the path itself by specifying the path i e source routing or the gateways connected to subnetwork 3 determine the optimal based on time cost or security path using so called routing tables The ISO standard for layer 3 is ISO 8473 Since this standard assumes that each station within the total network has a unique address 48 bit addresses are used i e one network can contain more than 10 EXP 14 stations Source routing is not provided 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the
75. hich tell it where the destination address is located The criteria e g time cost optimized and so on to be used by the gateway when selecting the route can be specified The gateway adapts the format to the requirements of the particular network For example a CSMA CD network uses a maximum packet length of 1500 bytes while an X 25 network works with 128 byte packets The gateway must segment the 1500 byte packet into 12 X 25 packets and reassemble the packet on the other side In addition the gateway can inform the sending stations of any errors In summary the services of layer 3 ISO 8473 are usually only required for gateways Gateways which only perform protocol conversions up to layer 3 are often called routers while gateways are generally thought of as protocol converters up to layer 7 4 3 3 The Network Layer in Accordance with ISO 8473 A PDU i e Protocol Data Unit of layer 3 consists of two parts i e the header portion and the data portion The header portion contains all layer 3 information ISO 8473 provides for connectionless datagram communication i e each packet contains all information required for it to be sent from the sender to the receiver No virtual connection is established no response acknowledgment of correct receipt is made and naturally the flow is not monitored Use of ISO 8473 is only recommended when used together with the ISO 8073 transport protocol which provides the auxiliary services mentioned
76. idge 71 4 3 2 4 The Programmed Bridge 71 4 3 2 5 The Bridge with Source Routing 72 4 3 2 6 Source Routing Explained by Fig 52 72 4 3 2 7 The Gateway 73 4 3 3 The Network Layer in Accordance with ISO 8473 74 4 3 3 1 Fixed Portion 76 4 3 3 2 Address Portion 78 4 3 3 3 Segmentation Portion 78 4 3 3 4 Optional Portion 80 4 4 The Protocols of Layer 4 86 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e Z 49 911 544 27 0 e Fax 49 911 544 27 27 7 Contents 4 4 1 General 86 4 4 2 The Transport Layer in Accordance with ISO 8073 88 4 4 2 1 The Individual Transport Classes 88 4 4 2 2 The Individual TPDUs 91 5 LIST OF FIGURES 117 6 LISTOF ABBREVIATIONS 119 7 INDEX 121 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH How the INAT NetSpector Works 9 1 How the INAT NetSpector Works INAT NetSpector is a network analysis and logging tool designed for Ethernet networks Together with the included network card it offers a package which is easy and quick to install and which can be run under the operating systems Windows 95 Windows NT and OS 2 WS NetSpector File Edit View Tools Window Help pelala x elele yel E Fl No 183 Time 0 01913 Own S5 TCPAP 1 Own ddress Dest ddress Frames ype IP from 195 180 213 173 to 195 180 213 172 1 Leitrechner S5 TCPAP 2 657 55 TCPAP 2 Leitrechner 613 Roboter 1 Roboter 2 155 Roboter 2 Roboter 1 307 55 TCPAP 1 S5 TCPAP 2
77. ilters The frame list may remain empty due to the combination of capture and display filters Remember that selection only excludes a subset 3 8 2 Frame List Creation of the frame list is selected with the menu item Create Frame List in the Edit menu Depending on the size of the capture quite some time may be required to create the complete list 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 42 Analyzing the Capture ser Fer Lit heed Adderss DWF Anbeter 7 feabeter 1 DOA Alobater Mabiti 4 0 amp 5 TCRAP BS TCPAP 1 0 027393 Lekuine BFTCEPAPE Che SU TEPNE F Lelirachser Diii Lren SE TEPAP F dos STEPPI Leittechser TISEI SSTEPNPE Leitiechkei TOHE Leieeohnen SETECAPE amga Sic Sh TCREMP 2 al S4 TCPnP 56 TEPMP i TIES Leien BS TCP Z OR 5 TCPRP Z Leilrecheei DDE Flower I Rabar 2 DMT Hpbmer T Raheter 1 Cis STEPP 55 TEPAP 1 00735 Leiecchne SS TCP 2 ao Leithne 8S TCPAP E TOHI STERN Lelirecheer C00 Lekenchines sb IEFAF Z C0636 Uefeechrer fo TEP 4 006155 SS TCEPAPE Leitechier TIHE Letina 8S TCPAP 2 BORE SS TEPNPZ Lelirscheer Mitar Hpbi ft Kabesar 1 a z4 TEPP i fo TEMP 0679 2S TOPIPI ESTCAP 1 TOIIEE 4 Leimedine BS TCPAP E LOGE T4 TCRAP Lelinechosr OAIE ra Hrkiler I Haheier 4 057 Apboter Tkak nder 1 MDB SS TEPAPE BS TCP 1 O 01947 So TORAP BS TCRIP 1 MO TF TEPRP I S amp TCPAP 0 0 Le erchnen FEFFRFFEFFFF Moral Lefeechne
78. ing checked by the sender and from layer 2a to layer 3 i e datagrams without being checked by the receiver Type 2 Type 2 defines a service which establishes a logical connection transmits data over it and then disconnects this link again In addition it monitors the flow The elements of this type are a subset of the HDLC protocol for WAN There are two differences First only ABM i e Asynchronous Balanced Mode is permitted Second multiplex mode i e the simultaneous use of several virtual connections is made possible by using different SAPs Although type 1 procedures are permitted they should not be used Only type 1 LLC connections have been used for the CSMA CD protocols used up to now The DIN suggestion for standardization i e DIN 41103 for local networks states that stations must be able to answer XID or test packets although they do not have to be able to create them MAP and TOP only support type 1 LLCs In the IBM token ring concept type 2 LLCs are also used DIN 41108 1 Octet 1 Octet 1 or 2 Octets n Octets F Fig 28 Layout ofthe LLC layer 1099 002 Fax 49 911 5 44 27 27 e BB 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 58 The Protocols of Layer 2 4 2 3 1 Presentation of the Individual Bits DSAP MSB LSB SSAP n 5 ToooIoJoTedsTsTels Tells 0 t Fig 29 Addresses of the LLC layer given in octets Explanation When octets are not shown in individual
79. ion and are sent to the next higher layer in the correct order Layer 2 is made up of two sublayers i e layer 2a and layer 2b Layer 2a provides the physical connection and is responsible for code security Layer 2b provides the logical link to the next higher layer Layer 2a is also called the MAC layer i e media access while layer 2b is also referred to as LLC i e logical link 7 Octets 1 Octet 6 Octets 6 Octets 2 Octets n Octets 4 Octets Pream SFD Data J Fos Pream Preamble SFD Start Frame Delimiter 10101011 DA Destination Adress SA Source Adress Ll Length Indicator FCS Frame Check Sequence Fig 27 Layout of an 802 3 packet elements of the MAC layer 1099 002 Fax 49 911 5 44 27 27 e BB 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 56 The Protocols of Layer 2 4 2 2 The MAC Layer The physical connection i e which computer communicates with which computer is determined by SA and DA As the figure shows the destination address i e the address of the station for which the packet is intended is always sent first Since only one station can send at atime all other stations monitor this destination address and compare it with their own address When the addresses match the packet is accepted and transferred to the higher layers for processing Various standards e g Ethernet or XNS also permit broadcast and group addresses as destination addresses Ifthis is
80. ions See appropriate reference The control field of the test PDU MSB LSB 1 1 1 PF O O 1 1 Fig 36 The test control field This command is used to implement a loop back test from LLC to LLC All data in this test packet must be sent back unchanged by the receiving station i e the test packet is imaged and sent as an echo to the station which sent the command Since this portion has no effect on the higher layers it can be used to check the correct physical connection of a station to the network 1099 002 Fax 49 911 5 44 27 27 e BB 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 62 The Protocols of Layer 2 4 2 3 3 The Control Field in Type 2 PDUs A mode corresponding to the extended mode of the HDLC is used i e the sequence numbers have a length of seven bits l format PDUs are used for the data transmission S format PDUs are used for maintenance of the connection and the security of the data transmission U format PDUs are used to establish and disconnect the connection With type 2 connections between two LLCs can be established with U format PDUs and the data stream can be monitored via sequence numbers and error repair mechanisms i e requests for repetition Full duplex operation i e two connected stations can send and receive at the same time can be used for an established connection The powerful functions which do not become available until layer 4 of the ISO reference model
81. is included in these versions of OS 2 The program is called MPTN i e Multi Protocol Transport Network Step 1 Mount the network card in your computer Step 2 Start OS 2 and open the MPTN program In the protocol window select Other protocol When asked for the floppy disk insert Disk 2 2 and enter a Driver The driver installation finds the INAT NetSpector capture driver and copies it to your hard disk Step 3 Link the driver to the INAT NetSpector network card Step 4 Perform a system shutdown Start your computer again and make sure that all programs are loaded without error messages when the system boots 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 26 Software Installation Driver installation OS 2 version B with IBM LAN Requester 4 0 Installation with the following components O NetSpector under OS 2 O IBM LAN Requester 4 0 Note Step 1 Step 2 Step 3 Step 4 INAT GmbH You will need the IBM LAN Requester This is included with IBM LAN Requester 4 0 IBM Warp Connect or IBM Warp Server Mount the network card in your computer Install the drivers of your Network adapter as described in the manual of your network adapter If necessary set the desired parameters Place the floppy disk labeled NetSpector OS 2 in drive A Install the IBM LAN Requestor 4 0 and proceed as follows In the Window Network Adaptors gt Othe
82. is parameter indicates which protocol classes are supported as alternates It is not supported by class 1 For example if a station wants to have a class 4 connection but is also able to support class 2 connections the station enters class 2 in this parameter as an alternate class Parameter Code 11000111 C7 h INAT NetSpector notation alt_class Parameter Length n 4 at the most Parameter Value One byte per supported class h Acknowledge time This parameter is sent by the CR sending station for information purposes only to the remote station The confirmation time is the time which may pass between the receipt of a TPDU and the sending of the corresponding confirmation This parameter is only used for class 4 connections Parameter Code 10000101 85 h INAT NetSpector notation ack_time Parameter Length 2 Bytes 00000010 Parameter Value n a binary value which gives the time in milliseconds i Throughput Data throughput is the number of octets per second A maximum and an average data throughput can be specified Specification of the average value is optional This parameter cannot be used for class 0 connections Parameter Code 10001001 89 h INAT NetSpector notation throughput Parameter Length 12 or 24 Bytes Parameter Values Bytes 1 to 12 Maximum throughput Octets 1 to 3 Destination value sending and receiving station Octets 4 to 6 Lowest acceptable value S E Octets 7 to 9 Destination value E
83. itored Select the appropriate network card in the Network Adapter field Only one network card can be selected at a time Only one network card can be selected at a time 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 41 3 8 Analyzing the Capture In addition to hardcopy and files the Frame List the Frame detail the Frame Hex and the H1 connections window are available for analyzing frames with the INAT NetSpector Before frames can be analyzed the capture must be stopped and the entries selected in the Station List The frames can then be indicated in a wide variety of ways You can use display filters to mask out unwanted stations and frames The following functions can only be performed after capture has been stopped 3 8 1 Display Filters The following dialog appears with the menu item Display Filter in the Tools menu Display Filter x M Frame Types Only the Selected Edit C All but not the Selected Edit Cancel Help IV Multicasts Only the Selected Edit Allbut not the Selected Edit kt Fig 15 Dialog for the display filters The display filters are used in the same way as the capture filters For details see chapter 3 6 Capture Filter Filters for Frame Types Multicasts and Broadcast can be specified for the display f
84. lexing Separate Flow control with Checksum without Checksum Using of Not using of frozen Reference Numbers Repeat until Time Error Determining new order Idle recognizing Recognizing of Protocol Errors Separate and comprise Symbols of the table Function always available m Function may be available not necessarily o Function may be available if supported by other stations 1 Not available in class 2 if explicit flow conttrol is switched off Fig 60 Functions of the ISO transport protocol classes 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 91 Fig 64 presents and explains the class 4 TPDUs Each TPDU consists of a fixed portion and a variable portion Together both parts are called the layer 4 header The length of the header is defined in a length indicator byte preceding the header This length information specifies the number of bytes of the length byte itself If successive bytes represent a binary number the first byte to be sent has the highest significance 4 4 2 2 The Individual TPDUs Connection request CR To establish a connection the station desiring the connection sends this TPDU to the partner station together with information on the expected parameters of the connection CR_TPDU contains all important parameters of the transport connection If at all possible CR_TPDU sh
85. mine whether the final destination address is located on their other side i e network 1 or network 5 3rd step Since this is not the case they forward the packet as a broadcast packet and add their own address to the routing information B3 then sends destination address broadcast source address S1 routing information B3 final destination address S2 B1 sends also destination address broadcast source address S1 routing information B1 final destination address 4th to nth step This is how several packets finally reach S2 over many paths and with many different pieces of routing information n 1 th step S2 selects a route and sends a packet to S1 via this route This specifies the route In the future source routing will certainly be used more frequently for distributed LANs since itis very easy to implement and takes full advantage of a bridge Following this discussion of source routing we will now introduce you to the most complex link between several subnetworks the gateway or the router 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 74 The Protocols of Layer 3 4 3 2 7 The Gateway The gateway is a protocol converter It permits data from one LAN e g via an X 25 network to be forwarded to another LAN Since gateways have their own network addresses stations send packets to them A gateway handles routing automatically using address tables w
86. n SS TCP 2 ODN BE 8 amp TCRAP Leitrechimet Paramelee inm 195 160 203 070 80 1951 Te iow 155 180 2131 172 w 195 TTS Tor Ark Des 80 Sroteedit Seq FT Dietz Dieesfled POR EOT Ger FE Daien 20 ch ben El Sroteedit Seq FA Aik eaei FOO SeeCreda Seg FE fom 195 EET m 1965 190 212 188 TCE hmm 19516011108 so 195 OT LITE TEF ime 185 10 FU eo 18 1 TEE frome 15 160 137 TE Tee Data Drie E00 EOT Seg FE Dede 16 Aok Deste FOD SeeCreda 0 Seq FS Io 195 U0 5a 195 TL TER ima 19 VEN FELD VER ST TER hoe 195 160 03 ira Tem CAL SreRei 1900 Deae 0 ERIPEPEPCH 149 Ark Desie JA Grebe D Seq dl beeg i DA Dette 1 Srne 0 TRAR anise DE Derfel 0 Sache 1 Ack beein Ei Sreteedit 1 Seq FA Data Dci FOR EOT Seq FA Datien 2 Ack Des EGO Brocaeili Seq FI Ack De oie FON SecCreda Seq FE ima 1 100 201 i 195 ST Te ima 1 160 403 173 0 195 00 TER from 15 160 0 195 0 LTE TCE Data Dessflei E00 BOT Heg FS Dates 16 hok Meee FON Seclred amp 0 Seq FA ima 1 VE a a 19 AS a TECH ima 195 1 70 80 195 00 TER iom 155 180 213 172 05 195 190 21 173 TCF om 155 10 213 172 oo 195 190 21 173 TER oem 185 180 71 1 173 8 195 JAN ZI LITE TER AAP rarest Ack Deal ER Erti 1 Seq FI Data Dessflel FOR EOT Seq F3 Daten 9 ra EP EET ETE EET ALTE EL ECE ELE PE ELELELLELELLL Fig 16 Frame list The frame list contains a well organized list of the frames so that time and logical sequence can be analyzed The types of protocols transfer
87. nd the hex window Details of the frame are presented in plain text or in hex and ASCII Even when no protocol DLLs are available for a certain frame type these frames are shown decoded up to layer 2 The capture can be stored for later analysis or printout Network kK All Frames Network Card Speaker O All Frames in lt Sound NeSpDevDriver Capture Filter za Symbolic names g a 00 20 AF C6 BA 52 gt Control Station List Hard disk 2 Store Load Capture Buffer i Display Filter play Printer _ Printing E Extras Protocol File lt Options Setting of the DLLs Via Frame List va via FrameDetail Frame Hex NetSpect exe Via va Frames Fig 2 How the INAT NetSpector works 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 How the INAT NetSpector Works 11 1 1 What INAT NetSpector Gives You Executable under Windows 95 Windows NT and OS 2 Graphic multitasking user interface Object oriented user definable environment so that you can design and store your windows yourself The program can be controlled intuitively with the mouse or with the keyboard The program has
88. nection of the DC sending station Variable portion Checksum The checksum is calculated from all elements of the TPDU and consists of one record of two modulo 255 sums Parameter Code 11000011 C3 h INAT NetSpector notation checksum Parameter Length 2 Bytes 00000010 Parameter Value 2 Bytes checksum 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 104 The Protocols of Layer 4 Data DT This TPDU is used to send the actual user data via the transport connection Three different formats have been defined based on the transport class used li_4 Length Indicator Layer 4 mg TPDU Code 2 m Header EOT TPDU Number 3 Be Data 4 li_4 4 Fig 67 DT_TPDU normal format for classes 0 and 1 8 1 1 li_4 Length Indicator Layer 4 TPDU Code 2 dst_ref Destination Reference 3 dst_ref Destination Reference 4 m Header TPDU Number 5 Variable Portion Checksum 6 9 10 li_4 9 Fig 68 DT_TPDU normal format for classes 2 3 and 4 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 105 li_4 Length Indicator Layer 4 TPDU Code 0 0 0 0 2 dst_ref Destination Reference 3 dst_ref Destination Reference 4 EOT TPDU No Bits 25 31 5 Header TPDU No Bits 17 24
89. ng of the route 2nd byte Pointer to the end of the list The individual entries are arranged so that the latest entry is always located at the beginning of the list The first byte of each address entry always contains the length of the entry 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 84 The Protocols of Layer 3 The error report PDU This special PDU is used to determine errors which occurred along the transmission path When an instance detects an error which must lead to rejection of the PDU this instance sends an error report to the sender of this PDU provided that the ER bit is set in the fixed portion of the header The layout of an error report PDU is shown below Fixed portion Address portion Layer 3 Header maximal lengtr 254 Bytes Optional portion Reasons for rejection Error report data field Fig 59 The error report PDU The 5th byte of the PDU is always 00100001 b The destination address is the address of the originator of the rejected PDU The source address is determined by the instance which set up the error report PDU 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 85 Reasons for rejection C1 h Parameter length Two bytes Parameter value The first byte contains the t
90. nt Under Windows 95 the appropriate entry is made in system file autoexec bat 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Installation and Program Start 17 Under OS 2 the appropriate entry is made in the file config sys Note e In contrast to the parallel interface the serial interface being used by the dongle can no longer be used for connection of additional I O devices e Two modules can be mounted side by side on the serial interface 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 18 Hardware Installation 2 1 3 Technical Data of Hardlock Il Technical Data Storage temperature Operating temperature Humidity Dimensions incl plug connectors Plug connector connection Signal lines used Feedback line Current consumption Minimum operating voltage Battery Recovery time Max number in rows ASIC technology Complexity Key factor Module address factor Number of programming cycles INAT GmbH e OstendstraBe 115 25 C to 70 C 0 C to 70 C 20 to 80 relative humidity 44 5 x 54 7 x 16 mm DB 25 DATA 0 to DATA 7 BUSY INIT STROB GROUND BUSY FAN OUT 10 LSTTL lt 100 uA lt 2 mA serial D 90482 N rnberg lt 2 Volt None None Theoretically any 215 CMOS 1 u with E2 cells Approx 1300 gates 248 915 gt 10 000 1099 002 e 49911 54427
91. o the transport unit 00000011 The address is unknown 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 102 The Protocols of Layer 4 Variable portion a This parameter is defined by the user It contains additional information on disconnection of the connection Parameter Code 11100000 E0 h INAT NetSpector notation add_inf Parameter Length each value lt 128 Parameter Value Defined by the user b Checksum The checksum is calculated from all elements of the TPDU and consists of one record of two modulo 255 sums Parameter Code 11000011 C3 h INAT NetSpector notation checksum Parameter Length 2 Bytes 00000010 Parameter Value 2 Bytes checksum 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 103 Disconnect confirm DC This TPDU is sent by the station which has received a DR TPDU 8 1 li_4 Length indicator Layer 4 TPDU Code dst_ref Destination Reference dst_ref Destination Reference c Header src_ref Source Reference src_ref Source Reference Variable Portion 7 li_4 7 Fig 66 The DC TPDU Fixed portion li_4 Length of the Layer 4 Headers in Bytes the li_4 Bytes exclusively TPDU_Code 1100 C h dst_ref Insert here the src_ref of the remote station Src_ref No of the con
92. ontrol units Full duplex communication i e both stations of a transport connection can send simultaneously is possible O Multiplexing Several transport connections are supported by one network connection Again we will use the example of the file server which is to handle several PCs in one network at the same time Although our file server has one physical address to which all PCs send their requests it has many logical transport addresses which are used to distinguish between the individual transport connections O Chaining and splitting up again Various individual TPDUs can be combined into one group TPDU and sent The receiving transport layer splits up these TPDUs again and transfers the individual TPDUs to the respective transport connection Example A PC with a multi tasking operating system Several programs execute a file transfer simultaneously The transport layer combines the confirmation TPDUs of the individual programs into one TPDU Data TPDUs cannot be chained O Segmentation and reassembly The specified TPDU size can be selected without regard to the maximum TPDU size of the lower level layer The transport layer segments the TPDU so that it can be processed by the lower level layer On the receiving side the transport layer reassembles the individual TPDUs into the total TPDU Example Although large TPDUs e g 8092 bytes are desirable for the file transfer Ethernet can only transfer data packets with a maximum
93. ot check to determine whether all Uls which were sent have actually been received This is handled by the higher layers Full duplex operation i e user data can be exchanged simultaneously in both directions can always be used 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 61 The control field of the type 1 XID TPDU MSB LSB 1 0 1 PF 1 1 141 1 Byte 1 Byte 2 Byte 3 Fig 35 The XID control field The XID command i e exchange identification is optional The response XID is mandatory The P F bit can be disregarded for type 1 connections It can be 1 or 0 in the command The F bit of the response must always have the value of the received P bit If the command contains P 1 the response must contain F 1 If P 0 then F 0 The P F bit has more uses in type 2 connections See appropriate reference After the XID byte three additional bytes follow These bytes provide more details on the type of data communication In the command the sending station specifies which type it supports The response contains the specifications of the receiving station The XID command can be used for an echo test XID Broadcast zero address for a group determination XID group address for a test to determine whether the network contains double addresses and to poll the supported type The XID command has more uses in type 2 connect
94. ould not contain user data If this is unavoidable the user data should not exceed 32 bytes 8 1 li_4 Length indicator layer 4 TPDU code CDT Credit dst_ref Destination Reference 3 dst_ref Destination Reference 4 src_ref Source Reference 5 t Header src_ref Source Reference 6 class Class Variable portion 8 li_4 8 Fig 61 CR_TPDU 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 92 The Protocols of Layer 4 Fixed portion li 4 TPDU_Code CDT Dst_ref Src_ref Class Option Format Flow_control INAT GmbH e Length of the layer 4 header in Bytes the li_4 Bytes exclusively 1110 e h Assignment of the original credit 0000 Credit is the number of the TPDUs which the sending station may send without a confirmation of the receiving station The receiving station is able to tune the credit to their free receive buffer dynamically See also the following figure displaying mechanism of credits Is always zero in a CR_TPDU because the connect requesting station gets the number not before the CC_TPDU connection confirm from the remote station No of the connection which defines the establishing connection in the CR of the sending station Characterization of the layer 4 class which supports the connection 0000 class 0 0001 class 1 0010 class 2 0011 class 3 0100
95. outside network 4 Based on the routing information B3 recognizes that it must forward the packet 2nd step B3 accepts the packet and forwards it to network 5 destination address S2 source address S1 routing information B3 B4 B5 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Description of the ISO Communication Protocols 73 3rd step B4 accepts the packet and forwards it to network 2 destination address S2 source address S1 routing information B3 B4 B5 4th step B5 accepts the packet and forwards it to network 3 destination address S2 source address S1 routing information B3 B4 B5 The packet has reached S2 If S2 sends a packet in return the same route is used in reverse S2 sends a packet in network 3 destination address B5 source address S2 routing information B5 B4 B3 final destination address S1 and so on The routing information represents layer 3 of communication between stations S1 and S2 and enables the packet to be transmitted One more question remains How does S2 get the routing information There are two ways Either the routing information is permanently specified by the network manager or the following procedure is used 1st step S1 sends a broadcast destination address broadcast source address S1 routing information final destination address S2 2nd step B1 and B3 receive the packet and check to deter
96. r adapters select Please insert Disk 2 2 NetSpector 0S 2 gt A TREIBER MACS prompt the files are copied In the window Network Adaptors INAT NetSpector 3Com Etherlink III Adapter select gt Add In the window Current Configuration gt Edit please insert the presetted hardware values In the window Protocols gt other Protocols select gt A TREIBER PROTOCOL prompt gt OK Now the driver is copied to the hard disk INAT NetSpector driver select gt Add please selct also other protocols which you like to install gt OK Perform a system shutdown Start your computer again and make sure that all programs are loaded without error messages when the system boots 1099 002 e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49 911 544 27 27 Installation and Program Start 27 Note The directory A DRIVER VAR_B contains the CONFIG SYS and PROTOCOL INI files of a running installation These files can provide you with useful information when questions arise Driver installation OS 2 version C Version 2 x no further protocols Installation with the following components O NetSpector under OS 2 without further protocols Step 1 Mount the network card in your computer Step 2 Install the drivers of your Network adapter as described in the manual of your network adapter If necessary set the desired param
97. r layers e Connection establishment e Flow monitoring 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 89 Class 1 Simple class with simple error reconstruction This class was developed by CCITT for X 25 The TPDUs i e transport data units are numbered and flow monitoring is handled by the LLC layer or X 25 The following services are available e All services of class 0 e Expedited data communication e Connection establishment e Chaining and splitting up e Error reconstruction The following service must be provided by the lower layers e Flow monitoring Class 2 Multiplexing class This class is actually belongs to class 0 but with expanded capabilities Several transport connections can be performed on one network connection i e multiplexing If for example one station is a file server it can establish many transport connections simultaneously over one network connection If this is the case a class 2 transport protocol is recommended The following services are provided e All class 0 services e Multiplexing e Connection disconnection The following service must be provided by the lower layers e Flow monitoring Class 3 Multiplexing class with simple error reconstruction The following services are available e All class 0 to 2 services e Flow monitoring Class 4 Error detection and correction class Sinc
98. ransmitted 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg Ostendstra e 115 INAT GmbH 94 The Protocols of Layer 4 Fix Portion of the Headers 1 7 Parameter Code 8 li_c Parameter Length 9 Parameter Value 10 li_c Fig 63 Layout of the variable portion a Transport service access point identifier TSAP ID Parameter Code INAT NetSpector notation INAT NetSpector notation Parameter Length Parameter Value b TPDU size 11000001 C1 h for the calling TSAP t_ssap 11000010 C2 h for the called TSAP t_dsap not defined Identifier for the calling or the called TSAP This parameter contains the maximum size of the TPDU for the connection Parameter Code INAT NetSpector notation Parameter Length Parameter Value INAT GmbH OstendstraBe 115 11000000 CO h tpdu size 1 Byte 00000001 00001101 0D h means 8192 Bytes not in class 0 00001100 0C h means 4096 Bytes not in class 0 00001011 0B h means 2048 Bytes 00001010 0A h means 1024 Bytes 00001001 09 h means 512 Bytes 00001000 08 h means 256 Bytes 00000111 07 h means 128 Bytes 1099 002 e D 90482 N rnberg e 8 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 95 c Version number This parameter contains the version of the transport software used It is not used for cla
99. red via the network are also displayed The scroll bars to the right of the window and at the bottom can used to page through the list The Home and End keys are used to access the beginning and end of the frame list The highlight bar can be moved with PgUp PgDn and the arrow keys and with a single click of the left mouse button The following information is indicated for each frame e Number of the frame since the start of capture e Time difference of the frame from the previously indicated one or absolute time respectively e Own address of the sending station e Destination address e Length of the frame in bytes e Frame type e Parameters of the frame The frame on which the highlight bar is positioned is shown in detail in the Frame Detail window and in the Frame Hex 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 43 3 8 3 Meaning of the frame colours The frames are depicted with different colours in the frame list The frame colours do not depend on the kind of protocol that is used Colour Meaning green Connection establishement blue Data frame with INAT PLC Header light blau Data frame without INAT PLC Header red Connection disruption black Acknowledges 3 8 4 Frame detail The protocol display is accessed with the menu item Frame Detail in the Windows menu by pressing the Tab ke
100. rformed the message Cannot open Hardlock driver tells you that the driver installation has not yet been done e Select Cancel and install the INAT NetSpector drivers for the dongle routine The drivers you will find in the NetSpector installation directory which was created by the install wizard c inat netspect drv or in the directory which was creatad by the you alternatively e Installation of the dongle drivers under Windows NT The HARDLOCK SYS and the HLVDD DLL drivers are required to start the dongle version of NetSpector under Windows NT Install the Windows NT drivers as described below 1099 002 e Open the command line editor by selecting Start MSDOS command line e Change to the installation directory default c inat netspect drv with the command cd inat netspect drv If an old driver version already exists remove this version with the command HLDINST remove Remember Since this command deletes the HARDLOCK SYS and HLVDD DLL files and the applicable register entries no applications which access the dongle routine should be running when this command is executed Using the command HLDINST install installs the HARDLOCK SYS and HLVDD DLL drivers in the appropriate system directories Fax 49 911 5 44 27 27 e BB 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 22 Software Installation e Installation of the dongle drivers under Windows 95 The HARDLOCK VXD driver is required to
101. ro by the sending station oO Oo Oo Il 1 Tells the receiving station that the PDU is experiencing congestion along the transmission path i e the selected or specified route was not ideal c 1 Routing decisions should favor short transmission times over low cost 0 Low cost takes precedence over short transmission times a o0 Il put Routing decisions should favor low error probability over short transmission times i e a good connection takes precedence over fast transmission d 0 Vice versa Fast transmission takes precedence over a good connection e 1 Low error probability takes precedence over low cost e 0 Low cost takes precedence over low error probability Remember that although all options can be set by the sending station the transmission instances do not necessarily have to fulfill them e g not all gateways have several different sending methods at their disposal and so on CD h Priority one byte Designation Net_Opt The sending station may choose between 15 different degrees of priority The normal priority is 0 while the highest priority is 14 Priorities are used to provide special handling of packets during the transmission instances For example packets can be placed at the front of the sending queue on gateways Again the transmission instances do not necessarily have to fulfill this option Parameter length 1 Parameter value 00000000 B normal to 00001110 highes
102. ry in the list e Press Continue e Enter A NT in the input line e After OK is clicked the INAT NetSpector Capture is indicated e Select Install The driver is copied to the hard disk e The main window Network settings appears again Confirm with OK The NetSpector capture driver is linked If you are using several network cards in your system and if several cards are located in the same network not all protocols may be linked to all cards We recommend only linking the NetSpector capture driver to the NetSpector network card For information on these links see the Windows NT manuals Capture driver under Windows 95 Install the NetSpector driver as described below e Start Settings Control Panel in the Start menu e Open Network in the control panel e In Network select the Add Button e Now selct the Protocol list e Confirm the Add button e Confirm the Have Disk button e Enter a Win95 in the input line e Confirm with OK e From the list of protocols select INAT NetSpector Capture e Confirm with OK e Confirm the Network window with OK 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg 49911 54427 0 e Fax 49911 5 44 27 27 Installation and Program Start 21 2 2 1 2 Installation of the hardlock driver by hand e The hardlock driver is automatically installed with the first installation of the netspector If the installation was not pe
103. s you to decide where the protection hardware will be used based on your own particular requirements A change in computers is no problem for Hardlock Il e Hardlock Il is transparent If your computer is only equipped with a parallel interface Hardlock Il can be easily installed between computer and printer e No strain on the interface Due to the CMOS technology used in the ASIC power consumption of Hardlock II in its idle state is so low that it can hardly be measured Since the operational range of Hardlock II in parallel mode extends to below 2 Volts minimum of 1 5 V power supply problems with weak interfaces can be avoided e Hardlock II can be mounted side by side Theoretically more than 32 768 modules can be mounted side by side on the parallel interface i e no remounting if you have installed several programs on a computer which are protected with Hardlock The appropriate module is located via its module address e All systems Hardlock Il can be used with all IBM compatible PCs and laptops 2 1 2 Installation on the Serial Interface If you do not want to use Hardlock II on the parallel interface the dongle can also be used on the serial interface Although in principle Hardlock Il can be operated at speeds of up to 115 200 Baud serial data processing speeds are naturally slower than when parallel interfaces are used Maximum data throughput is achieved with the parallel interface When Hardlock II is used on the seri
104. sion protocol identifier extension At this time this byte can only assume one value Net_version 01 h Version 1 of the ISO 8473 protocol 4th byte Designation Lifetime When no fixed routing from the source station to the destination station has been selected segments or even whole datagrams may be caught in endless loops due to routing errors or run times This wastes network resources unnecessarily In addition the transport layer above can only function reliably when the time during which a packet is present in the network is finite since flow monitoring assumes that only a limited number of packets of a transport connection can be present at one time on the network since the sequential numbers are repeated cyclically To prevent packets from being caught in the network in endless loops each PDU is provided with the maximum permissible presence in 500 msec units when sent Each gateway which is passed decrements this value based on certain delays on certain paths It is not necessary to reduce Lifetime to an exact time value since this would require a worldwide synchronous clock pulse For example ISO 8473 recommends using a delay of 20 msec for a transmission path For details see annex B of ISO 8473 Since every gateway functions according to the store and forward principle combined with waiting queues delays which affect Lifetime also occur on the gateway itself When a packet is segmented all segments receive the sam
105. ss 0 Parameter Code INAT NetSpector notation Parameter Length Parameter Value d Security parameters INAT NetSpector notation Are not specified in the norm e Checksum 11000100 C4 h vers_nr 1 Byte 00000001 00000001 01 h security This parameter is only defined for class 4 The checksum is calculated for all elements of the TPDU and consists of one record with two modulo 255 sums Parameter Code INAT NetSpector notation Parameter Length Parameter Value 11000011 C3 h checksum 2 Bytes 00000010 2 Bytes Checksum f Additional option selection This parameter contains additional transport parameters of the partner station It is not used for class 0 Parameter Code INAT NetSpector notation Parameter Length Parameter Value The basic setting is 0001 i e 1099 002 Fax 49 911 544 27 27 T 49 911 544 27 0 11000110 C6 h add_opt 1 Byte 00000001 0000 wxyz w 1 expedited data in class 1 w 0 no expedited data in class 1 x 1 Connect confirm in class 1 Explicit confirmation in class 1 16 Bit Checksum in class 4 should be used 16 Bit Checksum in Class 4 should not be used Use of expedited data transport service No use of expedited data transport service expedited data communication can be used e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 96 The Protocols of Layer 4 g Alternate protocol class es Th
106. st to the segment_length of the fixed portion total_length specifies the total length of the basic PDU This value must be identical in all segments of the basic PDU It includes header and data 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 INAT GmbH 80 The Protocols of Layer 3 4 3 3 4 Optional Portion The optional parameters are transferred in this portion of the PDU Each parameter consists of a parameter code i e which parameter a parameter length i e how long is the option and the parameter value i e what are the contents of the parameter A parameter may only be present once in the PDU Parameter codes FF h and 00xxxxxx b are not permitted The parameter length specifies in bytes the length of the parameter without parameter code and without the parameter length itself Parameter code Byte n 254 15 length of address portio Parameter length n 1 Parameter value n 2 to n 2 parameter length Fig 57 Layout of the parameters The following parameters are presently defined by ISO 8473 i e only seven different 1st bytes are available CC h padding one byte Designation Net_Opt This parameter can be used to increase the length of the header as desired The other bytes do not contain relevant information The decoding software does not offer further explanation 1 2 Parameter length Variable one byte 1 3 Parameter valu
107. start the dongle version of NetSpector under Windows 95 Install the Windows 95 drivers as described below Open the command line editor by selecting Start MSDOS command line Change to the installation directory default c inat netspect drv with the command cd c inat netspect drv If an old driver version already exists remove this version with the command HLDINST remove Remember Since this command deletes the HARDLOCK VXD file and the applicable register entries no applications which access the dongle routine should be running when this command is executed Using the command HLDINST install installs the HARDLOCK VXD driver in the standard Windows directory More information about the HDLINST command you will get with entry HDLINST INAT GmbH 1099 002 Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Installation and Program Start 23 2 2 1 3 Starting the Program under Windows NT and Windows 95 There are several ways to start the program Start the program by double clicking the NetSpector Netzwerk Analyser icon If you want to start INAT NetSpector at the command prompt switch to the directory in which you have installed INAT NetSpector Then enter NETSPECT The following message INAT NetSpector Dongle Ea gt Hardlock not connected r Tt Ignore Cancel indicates that the dongle has not been correctly mounted on the serial or parallel interface 1099
108. suppress special kinds of the Protocol Activating the buttons Syn Fin Reset pure Acks and TCP data INAT data and INAT Life data Acks the corresponding frames are suppressed in the a Frame List Port Filter TCP IP communication between two Ethernet stations may take place via several ports You have three choices 1099 002 Fax 49 911 5 44 27 27 e B 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 50 Analyzing the Capture O Only the Selected You specify all ports which you want displayed in the Frame List O All but not the Selected You specify all ports whose frames you do not want displayed in the Frame List o Filters off The default setting is Filters Off The frame traffic of all ports is displayed 3 8 9 Printing The menu item Print in the File menu can be used to access the following dialog a Settings M Long Text Help MV Hex Dump from Frame 1 to Frame 47 Comment T Print to File Fig 24 Printing Attention After printing the Creation of the Frame List shoud be repeated Complete captures or only parts thereof can be printed for logging purposes or for a more detailed analysis Only the frames of the stations are printed which are selected in the Station List The set Display Filter and the options of the individual protocol DLLs apply here Various combinations can be selected I
109. t going e From where is the packet coming e Was the packet distorted during its transmission e How much information does the packet contain Before we move on to a discussion of the higher layers we will briefly explain some basic principles and definitions A layer executes certain services It has an interface to the next higher layer and to the next lower layer Individual services can be performed by the layer 2 without the aid of higher layers The individual services are accessed by SAPs i e Service Access Points SAPs are special software addresses Each unit of data which passes through a certain layer is provided with specific data from this layer thus becoming a PDU i e Protocol Data Unit of this layer For example the PDU of layer 2a is the total packet The PDU of layer 2b is the packet of layer 2a minus the preamble of the SFD the two addresses the length indicator and the FCS sequence 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 57 4 2 3 The LLC Layer The LLC layer handles the transmission of a packet between two stations without switching nodes in between Two classes are defined Class Only services of type 1 Class Il Services of type 1 and type 2 Type 1 Type 1 defines a service without a connection or confirmation i e all data are passed through from layer 3 to layer 2a without be
110. t priority C8 h Source routing one byte Designation Source_routing This option can be used by the sending station to specify the route that the packet is to take See Fig 52 Parameter length Variable one byte Parameter value Only two options are provided 1st byte 00000000 b Partial source routing requested or 1st byte 00000001 b Total source routing requested 2nd byte Specifies the offset of the next valid address relative to the beginning of the parameter This byte is reset by each transmission instance 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Description of the ISO Communication Protocols 83 1 1 1 0 0 1 000 Source Routing 2 0 0 0 1 10 1 O Parameter length 3 Parameter value 4 Offset of next valic address 5 1 Route address 6 Bytes 44 2 Route address 6 Bytes 17 23 Fig 58 Parameter setup for source routing CB h Recording of route one byte Designation Recording of route This option permits the route which the packet has taken to be specified in the packet Each gateway which is passed enters its address When a PDU contains this parameter all instances along the route are requested to enter their address Parameter length Variable one byte Parameter value Only two options are provided 1st byte 00000000 b Partial recording of the route 1st byte 00000001 b Total recordi
111. ts a text file or an executable program from being overwritten by accident The file extension also shows the type of file directly A blue window background in the Statistics window means that a capture is being loaded or saved Since some captures are lengthy storage may require time 1099 002 INAT GmbH e Ostendstra e 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 31 3 1 6 Opening the Capture A capture which has been saved can be read in again As with the save procedure the file must have the extension cap Before a saved capture can be loaded again a running capture must be stopped The contents of the capture buffer are deleted without an are you sure inquiry The following dialog appears when the menu item Open capture is selected under the File menu Open Capture Suchen in a NetSpect x i c a NetSpect cap Dateiname NEEREREEN Dateityp Capture Files cap 7 ee Fig 4 Dialog for opening the capture The file name under which you saved or opened the last time is already preselected A blue window background in the Statistics window means that a capture is being loaded or saved Since some captures are lengthy loading the capture in the RAM may require time 1099 002 Fax 49 911 544 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 32 The Station List 3 2 The Station List When a captur
112. uccessfully on your hard disk Step 2 Capture driver under Windows NT 4 0 Install the NetSpector driver as described below e Start Settings Control Panel in the Start menu e Open Network in the control panel e Since the NetSpector capture driver is a protocol select the protocol tab e Select the Add button e Since the NetSpector capture driver is stored on the floppy disk select Have Disk e Enter AANT or A Win95 in the input line e After clicking OK the INAT NetSpector Capture is indicated e Select OK The driver is copied to the hard disk 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 20 Software Installation e The main window Network appears again Confirm with OK The NetSpector capture driver is linked If you are using several network cards in your system and if several cards are located in the same network not all protocols may be linked to all cards We recommend only linking the NetSpector capture driver to the NetSpector network card For information on these links see the Windows NT manuals You can link the NetSpector capture driver to all cards Capture driver under Windows NT 3 5 Install the NetSpector driver as described below e Open the Control Panel e Inthe Control Panel open Network e Select the software button e Select Others in the network software list This is the last ent
113. uded in the capture The following dialog appears for both selections after the Edit button is clicked Capture FilterStations Capturing only the selected ones x New Station Selected Stations INAT 002140010002 SPS1 Add gt gt Available Stations INAT 002140020002 SPS2 INAT 002140050056 INAT S5 TCP IP 2 Help 000000000000 SSTCP IP 2 030000000001 INAT 00214005005F INAT S5 TCPAP 1 FFFFFFFFFFFF 3com 0020D58001ED Siena 3com 002005800450 SPS1 ICcardO080C885CEBC INAT 002140000072 INAT 002140000088 INAT 002140010002 SPS1 INAT 002140020002 SPS2 INAT 002140050056 INAT S5 TCPYI IMAT ANPANNENNEEIMAT CR TCO AM Add Remove Cancel eit Fig 9 Dialog for the station capture filters Capture FilterStations l Ea Capturing all but not the selected ones OK Fig 10 Dialog for the station capture filters All but not the selcted ones If the INAT NetSpector receives a frame from an unknown station during capture the Ethernet address of this station is entered in the Available Stations list You can enter an Ethernet address in the New Station field and add it to the Selected Stations list by clicking the Add button You can also select a station in the Available Stations list and add it to the Selected Stations list with the Add button You can also obtain the same result by double clicking an entry in the Available Stations list If you want to r
114. vidual segments so that these can be reassembled correctly by the receiving station The optional portion permits the use of various services e g certain transmission security procedures recording of the route priorities error transmittal and so on The individual parameters will now be explained in more detail The nomenclature of the data monitor of the INAT NetSpector will be used for the short designations 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 76 The Protocols of Layer 3 4 3 3 1 Fixed Portion The fixed portion consists of nine bytes 1st byte Short designation NLPI network layer protocol identifier At this time this byte can only assume two values NLPI 81 h The PDU is designed in accordance with ISO 8473 NLPI 00 h_ The network layer is empty The packet remains in the source LAN Routing is not supported No layer 3 information follows 2nd byte Short designation Li_3 length indicator_3 The length of the layer 3 header is indicated including NLPI and Li_3 If a packet is transmitted in segments this length may not be change in the individual segments i e the header must always contain the same information in the individual segments Since this length indicator has a length of only one byte the maximum length is 254 bytes The 255 byte length is reserved for future expansions 3rd byte Short designation Net_version ver
115. w If the capture had been stopped the background of the window is white toa Statistics Frames 43 Bytes 3733 0 Lost D Fig 7 Statistics 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 34 Presettings The Statistics window offers the following information on the capture buffer e Frames Number of frames e Bytes Number of bytes e Capacity used in e Lost Number of frames which were not captured due to poor computer performance or an overloaded computer 3 5 Presettings At the beginning no explicit settings must be selected for the capture NetSpector comes with the following presettings e Write in a ring buffer e Size of the ring buffer 5 MB network card selected card 0 e All capture filters disabled e All display filters disabled e All protocol related filters disabled e Noise disabled e All files in which NetSpector stores the parameters station names and captures are located on the hard disk and in the directory under which NetSpector is installed 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Working with INAT NetSpector 35 3 6 Capture Filter 3 6 1 Working with NetSpector without Filters If all stations which are participating in active frame communication on your network are to be captured all filters remain disabled All filters can be disabled in the Tools menu
116. y several times or by double clicking an entry in the Stations List This window is divided into two areas e The top part contains a short description of the frame e In the bottom part of the window the frame is dissected into its single elements Each logical level has its own prefix The contents of this field also depend on the options which have been set for the appropriate protocol Frames for which no protocol DDL exists are decoded up to layer 2a For the meaning of the individual parameters see the descriptions of the individual protocols further back in this manual e g the protocol description of SINEC H1 Make the following settings to obtain a clear view of the capture with the frame detail Set the Frame Detail to maximized screen by clicking the maximize icon Using the PgUp PgDn or arrow keys move the highlight bar to the desired frame The Frame Detail appears when the desired frame is double clicked You can page to the previous or the next frame with the key combination Alt PgUp or Alt PgDn or with the menu items Previous Frame and Next Frame in the View menu If the frame is too large for the window you can scroll through it with the arrow or PgUp PgDn keys 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 44 Analyzing the Capture S NetSpector Frame Detail File Edit View Tools Window Help Delale x alee SE Bl R o
117. you an overview of the remaining memory space on all of your drives e Using the Install button start the installation e After the first floppy disk has been copied you will be asked to insert the second floppy disk which is labeled NetSpector OS 2 Disk 2 2 Continue is used to continue the copy procedure for the second floppy disk e After the second floppy disk has been copied a message to this effect appears The program has now been installed successfully A folder called NetSpector Network Analyzer has been set up in your work area Open this folder and two icons appear NetSpector Network The network analysis tool NETSPECTOR Analyzer Installation Utility A utility program to remove the NetSpector network analyzer from the computer and install updates 1099 002 INAT GmbH e OstendstraBe 115 e D 90482 N rnberg e 49911 54427 0 e Fax 49911 5 44 27 27 Installation and Program Start 25 Next the drivers for the capture must be installed These drivers are also located on the floppy disk labeled NetSpector OS 2 Disk 2 2 which is already in the floppy disk drive Note Check the entry IOPL in the Config sys file before installing the dongle drivers The standard entry is shown below IOPL YES Add this entry if it does not exist or change the existing entry to conform to the above entry Driver installation OS 2 version A Warp Version 4 Connect or Server The installation of network drivers
118. ype of error Ifthe error can be associated with a certain field the number of the first byte of this field is entered If the error cannot be localized or if a checksum error has occurred the value of the second byte is always zero The following errors have been defined Byte1 Byte2 Error class Meaning 0000 0000 General Reason not specified 0001 Error in Protocol Procedure 0010 Incorrect Checksum 0011 PDU rejected due to Traffic Jam 0100 Header Syntax Error 0101 Segmentation necessary but not allowed 0110 Received incomplete PDU 0111 Option Duplication 1000 0000 Address Destination Address not achievable 0001 Destination Address not known 1001 0000 Source Source Routing Error not specified 0001 Routing Syntax Error inthe Source Routing Field 0010 Unknown Address in the Source Routing Field 0011 Path not acceptable 1010 0000 Lifetime End of Lifetime during Transit 0001 End of Lifetime during Reassembling 1011 0000 PDU Option not supported 0001 rejected Protocol Version not supported 0010 Option Security not supported 0011 Option Source Routing not supported 0100 Option Recording of Route not supported 1100 0000 Reassembly Interrupt during Reassembling 1099 002 Fax 49 911 5 44 27 27 e 49911 54427 0 e D 90482 N rnberg e OstendstraBe 115 e INAT GmbH 86 The Protocols of Layer 4 4 4 The Protocols of Layer 4 4 4 1 General Layer 4 is the highest data communication layer and exclusively concerns transport

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