Monitoring VTAM

The term monitor means to watch something change, in order to ensure that the network is operating as planned. As you monitor VTAM®, you can check on the status of the sessions between resources by using the various DISPLAY commands. A DISPLAY command enables VTAM to show information about your workstation screen.

This topic does not provide details of what each of the commands can do. You can find details about specific commands in VTAM operator commands.

Using the DISPLAY commands, you can see the status of the network or its resources. Status shows whether the network or its individual resources are up (active) or down (inactive). DISPLAY commands also provide information about which resources have been defined to VTAM and where they are in the network hierarchy.

The following example illustrates the use of a DISPLAY command. The operator for the sample network shown in Figure 1 enters the following DISPLAY command:

d net,id=CICS01,scope=all

Note: In VTAM, the operator can use the abbreviation "d" instead of "DISPLAY" in the command DISPLAY NET,ID=CICS01,SCOPE=ALL.

Within this topic, the abbreviated forms of commands (d=DISPLAY, v=VARY, and f=MODIFY) are used. VTAM accepts commands in either lowercase or uppercase.

The displays shown in the scenarios might differ from what you would see in your network. For example, if the MSGMOD=YES start option is specified in your network, the output would differ from these samples, which reflect MSGMOD=NO.

When you enter this command, VTAM shows all active sessions with the CICS01 application program. Details about this and other commands used in this scenario are provided in VTAM operator commands.

The display shows VTAM's response:

d net,id=CICS01,scope=all
IST097I DISPLAY ACCEPTED  
IST075I NAME = NETA.CICS01, TYPE = APPL  
IST486I STATUS= ACT/S, DESIRED STATE= ACTIV  
IST977I MDLTAB=***NA*** ASLTAB=***NA***  
IST861I MODETAB=***NA*** USSTAB=***NA*** LOGTAB=***NA***  
IST934I DLOGMOD=***NA*** USS LANGTAB=***NA***  
IST597I CAPABILITY-PLU ENABLED  ,SLU ENABLED  ,SESSION LIMIT NONE  
IST231I APPL MAJOR NODE = APPL1A  
IST654I I/O TRACE = OFF, BUFFER TRACE = OFF  
IST271I JOBNAME = ECHO, STEPNAME = ECHO, DSPNAME = 0AAACIST  
IST228I ENCRYPTION = OPTIONAL, TYPE = DES  
IST1050I MAXIMUM COMPRESSION LEVEL - INPUT = 0, OUTPUT = 0  
IST171I ACTIVE SESSIONS = 0000000002, SESSION REQUESTS = 0000000000  
IST206I SESSIONS:  
IST634I NAME     STATUS         SID          SEND RECV VR TP NETID  
IST635I L3A3278A ACTIV-S    EAABEEC3FF8D8965 0000 0000  4  0  NETA  
IST635I L3A3767A ACTIV-P    F6ABEEC3028D8998 0000 0000  4  0  NETA  
IST314I END

Note: The highlighted fields and values in this and later samples are explained in the text.

In this display:

IST486I indicates that the application program is active with sessions (ACT/S) and that the desired state for this application program is active.
IST171I shows that there are two sessions with this application program and that no session requests are pending.
IST635I lists the logical units that are in session with this application program.

In your network, you can also display information about physical and logical resources, check to see whether your domain's VTAM is connected to any other VTAM domains, and view routes (logical connections) that are being used.

The operator enters another DISPLAY command as follows:

d net,id=LN3A1,scope=all

The operator uses this command to display line LN3A1 and the resources that are attached to the line.

The display shows VTAM's response:

d net,id=LN3A1,scope=all  
IST097I DISPLAY ACCEPTED  
IST075I NAME = LN3A1, TYPE = LINE  
IST486I STATUS= ACTIV, DESIRED STATE= ACTIV  
IST087I TYPE = LEASED             , CONTROL = SDLC  
IST134I GROUP = GRP3A1,   MAJOR NODE = NCP3AA1  
IST084I NETWORK NODES:  
IST089I P3A3767A TYPE = PHYSICAL UNIT    , ACTIV  
IST089I L3A3767A TYPE = LOGICAL UNIT     , ACTIV  
IST089I P3A3274A TYPE = PHYSICAL UNIT    , ACTIV  
IST089I L3A3278A TYPE = LOGICAL UNIT     , ACTIV  
IST089I L3A3278B TYPE = LOGICAL UNIT     , NEVAC  
IST089I L3A3290A TYPE = LOGICAL UNIT     , ACTIV  
IST314I END

In this display:

IST087I indicates that the line is a leased (nonswitched) line.
IST089I shows two physical units and four logical units attached to the communication controller.
One of the logical units (L3A3278B) has never been activated (NEVAC).

The operator enters another DISPLAY command as follows:

d net,id=L3A3278B,scope=all

VTAM displays the following information about logical unit L3A3278B:

d net,id=L3A3278B,scope=all  
IST097I DISPLAY ACCEPTED  
IST075I NAME = NETA.L3A3278B, TYPE = LOGICAL UNIT  
IST486I STATUS= NEVAC, DESIRED STATE= INACT  
IST977I MDLTAB=***NA*** ASLTAB=***NA***  
IST861I MODETAB=MODETAB2 USSTAB=***NA*** LOGTAB=***NA***  
IST934I DLOGMOD=***NA*** USS LANGTAB=***NA***  
IST597I CAPABILITY-PLU INHIBITED,SLU INHIBITED,SESSION LIMIT 00000001  
IST081I LINE NAME = LN3A1, LINE GROUP = GRP3A1, MAJNOD = NCP3AA1  
IST135I PHYSICAL UNIT = P3A3274A  
IST082I DEVTYPE = LU  
IST654I I/O TRACE = OFF, BUFFER TRACE = OFF  
IST228I ENCRYPTION = NONE, TYPE = DES  
IST171I ACTIVE SESSIONS = 0000000000, SESSION REQUESTS = 0000000000  
IST172I NO SESSIONS EXIST  
IST314I END

In this display, IST486I indicates that the current state of the logical unit is NEVAC, which means the logical unit was never activated, and that the desired state is INACT. It indicates that VTAM is not attempting to activate its subordinate resources because no request was made to do so.