Set Up a Simple P2P Configuration to Test TCP/IP Connectivity

CA Vtape P2P Option › Set Up a Simple P2P Configuration to Test TCP/IP Connectivity

Set Up a Simple P2P Configuration to Test TCP/IP Connectivity

CA Vtape P2P normally requires more than one SVTS complex. Several SVTS subsystems on one or more LPARs, sharing the same set of GLOBAL and BSDS1 data sets, are all considered part of the same SVTS complex. Separate SVTS complexes or subsystems require separate sets of DASD cache, and GLOBAL and BSDS1 control files. Learning to use CA Vtape P2P in this type of environment may seem complex. We therefore recommend starting with a small CA Vtape P2P parmlib configuration designed simply to test TCP/IP connectivity. This configuration will only consist of a single SVTS subsystem and will not require any remote virtual tape unit (VTUs), groups, or data filters.

As stated previously, the purpose of this configuration is to test easily that you can properly define CA Vtape P2P and establish connectivity through TCP/IP. To test TCP/IP connectivity through a single system you will be utilizing the TCP/IP loopback IP address 127.0.0.1. This will allow you to configure the SVTS subsystem as a remote system to itself. While you will not be able to test a remote Virtual Tape mount, you will be able to test connectivity by utilizing remote SVTS commands and thereby confirm that CA Vtape P2P connectivity is working properly with your TCP/IP stack.

To set up a simple CA Vtape P2P configuration

Configure the VTP2POPT parmlib member. While most of the default attributes will suffice, the most important attributes to consider in this member are:
TCPNAME=$NULL

This attribute is normally assigned the job or task name of the TCP/IP stack running on your zOS/390 system.

ListenOnPort=1100&SVTS(-1:1)

This attribute assigns the port number used by the P2P Listener. The default value assigns 1100n where n is the SVTS subsystem number, that is, from 1 to 8 (effectively 11001 to 11008).

Note: If these port numbers conflict with other numbers on your system you can change the port number prefix, that is, change the number to something like 1200&SVTS(-1:1)
Configure the VTP2PRMT parmlib member. For now we recommend simply defining the local system as a remote system. This will allow you to test connectivity by sending remote commands to the local system.
In VTP2PRMT define the local system as remote system named localhost, for example:
```
<PeerToPeerRemotes>
    RemoteSystem=LocalHost

<LocalHost>                            
   Port = 1100&SVTS(-1:1)
   IPAddress = 127.0.0.1
   ConsoleSuffix = LCL&SVTS(-1:1)
```
In this case the port number must match the ListenOnPort attribute value defined in the VTP2POPT member.

Note: If you specified a ListenOnIPAddress attribute in VTP2POPT, then the IPAddress must also match that attribute. If you did not specify a ListenOnIPAddress attribute then the loopback address, 127.0.0.1 should work.

In this example, we have chosen a ConsoleSuffix of LCLn where n is the SVTS subsystem number 1 to 8. The ConsoleSuffix is a user defined four character value used to uniquely identify the remote system when issuing remote SVTS commands or displaying remote console text.
In the parmlib <directory> section of VTPARMS, configure the PeerToPeerOptions and PeerToPeerRemotes attributes to point at VTP2POPT and VTP2PRMT members.
Run the SVTPARMS batch job to validate that you have properly configured your parmlib options. Correct any parmlib configuration problems before continuing.
If your TCP/IP Stack is active, restart SVTS. At startup SVTS should display several messages indicating that CA Vtape P2P is active, for example:
```
SVT1TP208I RC=0,0,P2P@MCSX,EMCS Console SVT7XE61 activated
SVT1TP000I Console routed to LOCAL
SVT1TP501I RC=0,0,P2P@LSTN,Host XXI161ME, 41.202.65.61
SVT1TP500I RC=0,0,P2P@LSTN,Listening on 0.0.0.0:11001
```
The first SVT1TP500I message indicates the default IP address of the TCP/IP stack (41.202.65.61 in this example). The second message indicates that the P2P Listener has established a TCP/IP socket and is waiting for remote connections on the given IP address (0.0.0.0) and port (11001).

Note: The default ListenOnIPAddress attribute in VTP2POPT is 0.0.0.0. This allows the P2P Listener to accept connections from any IP address connected to the TCP/IP stack.

Issue a SVTS D P (display parmlib) command. This will record the parmlib settings on the console log and show both the CA Vtape P2P options and remote systems as defined by parmlib, for example:

PeerToPeerOptions initialized from Parmlib member: VTP2POPT
   ProtocolFamily................. IPV4
   TCPName........................ TCPIP61
   DsnameSYSTCP................... VTAM.TCPIP.TCPIP.DATA
   ListenOnPort................... 11001
   ListenOnIPAddress.............. $NULL
   MaxClients..................... 4
   IdleTaskTimeout................ 30
   EMCSTerminalPrefix............. SVT, EMCS CN=SVT1XX61
PeerToPeerRemotes initialized from Parmlib member: VTP2PRMT
   LCL1 LocalHost….......... 11001 127.0.0.1

Issue a SVTS D R (display remotes) command. This command will show the connection status of any of the defined remote systems, for example:

SVT1 D R
SVT1TP403I Display Remote Statistics
Rmt  Status       AsOf   #Receive     #MB Files #Transmit     #MB Files
---- ------------ ----- --------- ------- ----- --------- ------- -----
LCL1 Active       15:08         5       1     0         5       1     0
----------------------- --------- ------- ----- --------- ------- -----
1 Remote System(s)              5       1     0         5       1     0

In the example above note that it shows that LCL1 is active and that we have been able to send and receive data from it.

You should now be able to issue remote SVTS commands and effectively test the ability of CA Vtape P2P to communicate with itself as the localhost remote system.
Note: One of the features of CA Vtape P2P is that it allows you to direct any normal SVTS commands to a connected remote system. This is accomplished by appending the console suffix to the SVTS console command prefix using either a period or a slash character. For example:

SVTn D H is the normal SVTS display help command. To route that command for execution to the localhost remote system simply append its console suffix LCL1, that is, SVT1.LCL1 D H or SVT1/LCL1 D H

Try a simple command, such as: SVT1.LCL1 D S (display status) or SVT1/LCL1 D H (display help).

SVTS operator commands entered in this manner will be transmitted by the local system to the remote system for execution. SVTS console output displayed by the remote system command will then be transmitted back to the local system. There, the console suffix will prefix the remote console output to distinguish its source. For example:
```
SVT1.LCL1 D S
SVT1TP204I Command for LCL1, LocalHost scheduled
LCL1X0224I Subsystem Status Display
     Field               Current State
     ------------------- -------------------
     Release             r11.5
     Subsystem           Active
     … 
     Recall Order        Primary
     Console             Local
LCL1X0100I Command Complete
```
Note: The console suffix 'LCL1' was also used as a prefix for messages displayed from that remote system. This allows you to determine from which remote subsystem that console output was derived.

You have successfully configure a small CA Vtape P2P parmlib configuration designed to test TCP/IP. In this case the remote subsystem was simply the loopback address.