Sample Trace of a Virtual Session Logon

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This record traces the first SNA command that an application sends to the terminal during session initiation. This is a BIND from application VTAMPLUS to virtual terminal VTERM000 (this establishes a virtual session). In the example that follows, VTAMPLUS is the CL/SuperSession operator facility application. There is a concurrent session between GATEWAY and the physical terminal, PTERM (see Sample Trace of CL/SuperSession Main Menu). Applications like the CL/SuperSession operator facility (and TSO, CICS®, IMS, etc.) send screens to the virtual terminal on the virtual session. CL/SuperSession then makes sure that these messages are delivered to the physical terminal on the physical session. The physical session is the session between GATEWAY and the physical terminal. The virtual session is the session between the host application (that is, CICS, TSO, etc.) and the virtual terminal.

Note: IBM Support requires BIND RUs containing bind images for the physical and virtual sessions in order to analyze VTAM-related problems. Make sure that you have captured BIND information in the trace data before you send it in. BINDs contain critical session rules that the virtual and physical sessions require in order to communicate.

Figure 1 has a sequence number of 000E and a segment number of 0000.

Figure 1. Application Sends BIND to Virtual Terminal


USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ000E SG0000 KLKVTXSC VTERM000/VTAMPLUS READONLY BIND REQ RF0000 SQ0000 SN00000000 OC  DR1
          RU 31010303 B1903080 008087C7 80000200 00000000 18502B50 7F00000 7 E5E3C1D4 *..........gG.........&.&"...VTAM* 
             D7D3E400 05000003 002308E5 E3C5D9D4 F0F0F060 1AD72B41 DB50CE9 E CB11D5C5 *PLUS.......VTERM000-.P...&....NE* 
             E3C9C4F0 F0F14BE7 E7E7C4D9 D4F2F50E 11F3D5C5 E3C9C4F0 F0F14BE 5 E3C1D4D7 *TID001.XXXDRM25..3NETID001.VTAMP*
             D3E42C0A 01084040 40404040                                               *LUS...
                TIME: A1AA74D3 345A0143 07:27:04.172960

Figure 2 is a continuation of the first GTF record. It is segment 0001 of sequence number 000E. It contains the last 13 bytes of data that completes the BIND RU started in the previous record segment.

Figure 2. Application Sends BIND to Virtual Terminal (continued)

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ000E SG0001
          DAT 40402D09 08C4F4C1 F3F2F7F8 F4                                           *  ...D4A32784 
                TIME: A1AA74D3 34645E43 07:27:04.173125

In Figure 3, VTERM000 issues VTAM® macro OPNSEC to accept the BIND. VTAM processes the OPNSEC request by creating an SNA positive response (+RSP) to the BIND.

Figure 3. Virtual Terminal Accepts BIND and Starts Session

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ000F SG0000 KLKVTAPI VTAMPLUS/VTERM000 OPNSEC DATA REQ RF0000 SQ0000 SN00000000 OC DR1 
                TIME: A1AA74D3 368FBA43 07:27:04.182011

This record contains another common SNA command, Start Data Traffic (SDT), which the application sends after establishing the session. VTAM automatically issues an SNA +RSP to the SDT; no action by VTERM000 is necessary.

Figure 4. Application Sends Start Data Traffic

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0010 SG0000 KLKVTXSC VTERM000/VTAMPLUS READONLY SDT REQ RF0000 SQ0000 SN00000000 DR1 
                TIME: A1AA74D3 38682641 07:27:04.189570

The BIND request (Figure 1 ) specified bracket protocol. Figure 5 indicates that application VTAMPLUS sent a BID command requesting permission to begin a bracket. This RU carries an SNA sequence number of SQ0001.

Figure 5. Application BIDs to Begin a Bracket

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0011 SG0000 KLKVTAPI VTERM000/VTAMPLUS RECEIVE BID REQ RF0000 SQ0001 SN00000000 OC DR1 
                TIME: A1AA74D3 413FEA43 07:27:04.225790

VTERM000 sends a positive response (+RSP) to the BID RU. (SNA sequence number SQ0001, which matches the sequence number in Figure 6, identifies this as a response to the BID.) Essentially, VTERM000 is saying to VTAMPLUS, “OK, you can talk to me.”

Figure 6. Virtual Terminal Accepts BID

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0012 SG0000 KLKVTAPI VTAMPLUS/VTERM000 SEND    BID RSP RF0000 SQ0001 SN00000000 OC DR1 
                TIME: A1AA74D3 645C7A43 07:27:04.369607

Figure 7 is a three-segment (SQ0013-SG0000, SQ0013-SG0001, SQ0013-SG0002) data message that VTAMPLUS is sending to the virtual terminal. The request (REQ) has an SNA sequence number of SQ0002. It contains the Entry Validation panel, which asks the user to enter a user ID and password. This message is not forwarded to the physical terminal because the initial dialog for APPLDEF VTAMPLUS is in effect.

Note: Initial dialogs are specified in the APPLDEF commands; see commands library member(KLSCAPLD). One of their functions is to simulate certain user tasks, such as typing a user ID and password.
Figure 7. Logon Entry Validation Panel Sent by Application to Virtual Terminal

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0013 SG0000 KLKVTAPI VTERM000/VTAMPLUS RECEIVE DATA REQ RF0000 SQ0002 SN00000000 OC DR1 BB CD
          DAT 7EC31D60 60606060 60606060 60606060 60606060 60606060 60606060 60606060 *-C.-----------------------------* 
              601DE800 C595A399 A800E581 93898481 A3899695 001D6060 60606060 60606060 *-.Y.Entry.Validation..----------* 
              60606060 60606060 60606060 60606060 60606060 00000000 C896A2A3 7A00E2E8 *--------------------....Host:.SY*
                TIME: A1AA74D3 6619EA43 07:27:04.376734                               *                                *

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0013 SG0001
          DAT E2C711C2 D1C481A3 857A00F0 F261F1F5 61F9F000 00C485A5 8983857A 00D9C7C5 *SG.BJDate:.02/15/90..Device:.RGE* 
              D5F6F0F0 F111C361 E3899485 7A00F0F7 7AF2F77A F0F411D4 4DC98485 95A38986 *N6001.C/Time:.07:27:04.M(Identif* 
              898381A3 8996957A 11D55011 D5E5E4A2 85998984 1DE87E7E 7E6E1DC8 11D5F91D *ication:.N&.NVUserid.Y--->.H.N9.*
              6011D660 11D6F3D7 81A2A2A6 9699841D E87E7E7E 6E1D4C11 D7C91D60 11D750D5 *-.O-.O3Password.Y--->.<.PI.-.P&N*
              85A600D7 81A2A2A6 9699841D E87E7E7E 6E1D4C11 D76A1D60 11D94011 D9C5C184 *ew.Password.Y--->.<.P|.-.R .REAd*
              8489A389 96958193 00C99586 96999481 A3899695 7A115A50 115AE6C7 9996A497 *ditional.Information:.!&.!WGroup*
              1DE87E7E 7E6E1DC8 115AF91D 60115B60 115BF7C1 8383A31D E87E7E7E 6E1DC811 *.Y--->.H.!9.-.$-.$7Acct.Y--->.H.*
              5C6A1D60 115CF011 5DC7D799 96831DE8 7E7E7E6E 1DC8115D D91D6011          **|.-.*0.)GProc.Y--->.H.)R.-.    * 
                TIME: A1AA74D3 661C8043 07:27:04.376776

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0013 SG0002
          DAT 60601D60 11F2C111 F3501D60 C3969494 8195841D 607E7E7E 6E1D4011 F4601D60 *--.-.2A.3&.-Command.-===>. .4-.-* 
              C595A385 994040C6 F37EC5A7 89A34040 11D5F113                            *Enter  F3=Exit  .N1.
                TIME: A1AA74D3 661E7843 07:27:04.376807

Figure 8 is a +RSP from VTERM000 to VTAMPLUS. It carries an SNA sequence number of SQ0002, which matches the message in Figure 7. This is a positive response to the Entry Validation panel.

Figure 8. Virtual Terminal Acknowledges Receipt of Panel

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0014 SG0000 KLKVTAPI VTAMPLUS/VTERM000 SEND DATA RSP RF0000 SQ0002 SN00000000 OC DR1 BB 
                TIME: A1AA74D3 667AF943 07:27:04.378287

Figure 9 is a data request from VTERM000 to VTAMPLUS. It contains the user ID USER00 and password PSSWD1. The user at the terminal made no entries; the initial SSPL dialog issued a VSSTYPE command with USER00 and PSSWD1. The Change Direction (CD) bit is ON. This means that VTERM000 is locked for input until application VTAMPLUS unlocks it with another CD or End Bracket (EB).

Figure 9. User ID and Password Sent to Application by Virtual Terminal

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0015 SG0000 KLKVTAPI VTAMPLUS/VTERM000 SEND DATA REQ RF0000 SQ0001 SN00000000 OC XDR1 CD
          DAT 7DD7C711 D5F1E4E2 C5D9F0F0 11D7C1D7 E2E2E6C4 F1                         *'PG.N1USER00.PAPSSWD1 
                TIME: A1AA74D3 76DBAA43 07:27:04.445370

At this point, the initial dialog ends and messages from VTAMPLUS to VTERM000 must be delivered to the physical terminal. Figure 10 contains a message from VTAMPLUS to the virtual terminal. The RU contains Only in Chain (OC) and End Bracket (EB) indications, and requests a positive response.

Figure 10. Logon Message From Application Received by Virtual Terminal

USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ001A SG0000 KLKVTAPI VTERM000/VTAMPLUS RECEIVE DATAREQ RF0000 SQ0003 SN00000000 OC DR1 EB 
          DAT F1C311F5 E51DE8C1 60E5E3C5 D9D4F0F0 F0                                  *1C.5V.YA-VTERM000
                TIME: A1AA74D4 92835643 07:27:05.607221

Figure 11 indicates that VTERM000 sends a positive response to CL/SuperSession.

Figure 11. Virtual Terminal Acknowledges Logon Message


USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ001C SG0000 KLKVTAPI VTAMPLUS/VTERM000 SEND DATA RSP RF0000 SQ0003 SN00000000 OC DR1 EB 
                                TIME: A1AA74D5 A2930441 07:27:06.721584

In Figure 12 , the virtual terminal issues VTAM macro RESETSR to change the RECEIVE mode. The RESETSR entries that appear frequently in the traces are a VTAM application program interface convention and are not related to SNA data traffic in the network.

Figure 12. Receive Mode Change


USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0022 SG0000 KLKVTAPI VTAMPLUS/VTERM000 RESETSR NEXT 00000000 00000000
                                TIME:  A1AA74D5 ACB0A141 07:27:06.763018

Figure 13 indicates that GATEWAY is preparing to send an output message to the PTERM. At this time, the PTERM's keyboard is unlocked and PTERM owns the SNA direction indicator. GATEWAY sends an SNA SIGNAL request to ask PTERM to relinquish the SNA direction indicator.

Figure 13. GATEWAY SIGNALs for Send Direction


USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0023 SG0000 KLKVTAPI PTERM/GATEWAY SEND SIGNAL REQ RF0000 SQ0000 SN00000000 OC DR1 
                TIME: A1AA74D6 F41D8141 07:27:08.104152

Figure 14 indicates that the physical terminal sends a null RU (that is, no data) with the Change Direction (CD) indication, allowing GATEWAY to start sending data.

Figure 14. Physical Terminal Relinquishes Send Direction with Null RU


USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0024 SG0000 KLKVTAPI GATEWAY/PTERM RECEIVE DATA REQ RF0000 SQ0003 SN00000000 OC XDR1 CD 
                TIME: A1AA74D6 F42A8C41 07:27:08.104360

In Figure 15, GATEWAY delivers the logon message received on the virtual session (Figure 10 ) to the physical terminal.

Figure 15. GATEWAY SENDs Logon Message to Physical Terminal


USR4E 3E8 ASCB 00F5B600            JOBN KLK
          SQ0025 SG0000 KLKVTAPI PTERM/GATEWAY SEND DATA REQ RF0000 SQ0008 SN00000000 OC DR1 CD
          DAT F1C311F5 E51DE8C1 60E5E3C5 D9D4F0F0 F0                                  *1C.5V.YA-VTERM000 
                TIME: A1AA74D6 F6F87041 07:27:08.115847