Establishing CMAS to CMAS connections

If more than one CMAS is to be involved in the management of a CICSplex, you are recommended to create links between those CMASs. In this example, you will see how to define links between two CMASs, CMSSYS1 and CMSSYS2, which will both be involved in managing the CICSplex PLXPROD1.

Note that you must define the CMAS to CMAS links before defining CICSplex PLXPROD1 to the CMASs. If you define PLXPROD1 to the CMASs before creating the CMAS to CMAS links, a duplicate maintenance point condition is raised and the CMAS to CMAS connection is terminated.

The CMASs are running on separate MVS™ images, and their CASs (CASSYS1 and CASSYS2) are already connected. You have to create two links, one from CMSSYS1 to CMSSYS2, and one from CMSSYS2 back to CMSSYS1. Both CMASs should be running while you define these links.

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  1. Display any existing CMAS to CMAS links defined from CMSSYS1.
    1. From the main menu click Administration views --> CMAS configuration administration views --> CMAS to CMAS link definitions to open the CMAS to CMAS link definition tabular view.
    2. The context, which is displayed near the top of the tabular view, must be the CMAS for any configuration task. Start with CMSSYS1, if the context is not CMSSYS1, specify CMSSYS1 in the CMAS context field and click Refresh. The context is then fixed for all subsequent views and menus until changed.
  2. Create a new CMAS to CMAS link.
    1. Click Create to open the CMAS to CMAS link definition create view.
    2. Provide the following information:
      Target CMAS name
      CMSSY2
      Description
      Link to CMSSYS2 on system 2
      Target CMAS VTAM application ID
      CMSSYS2
      Target CMAS system ID
      CM2B
      Link protocol
      LU62
      Send buffer size
      4060
      Receive buffer size
      4060
      Type of attach-time security to be used
      LOCAL
      Other fields can remain blank.
    3. Click Yes to confirm.

      The CMAS to CMAS link definition view is redisplayed, and includes an entry for the link you have just created. This confirms that the link from CMSSYS1 to CMSSYS2 has been defined in the data repository of CMSSYS1. Now you have to create the corresponding link from CMSSYS2 to CMSSYS1.

  3. Change the context. 1

    From the CMAS to CMAS link definition view, type CMSSYS2 into the CMAS context field and click Refresh. (Remember that you need to store this definition in CMSSYS2’s data repository, and so CMSSYS2 must be the context.)

    The CMAS to CMAS link definition view is refreshed to show any CMAS to CMAS links that have already been defined to CMSSYS2.

  4. Repeat step 2, using appropriate data for a link from CMASSYS2 to CMASSYS1.
  5. End of change

Start of changeA two-way link has now been created between CMSSYS1 and CMSSYS2. The link is available immediately: you do not have to restart the CMASs first. When the CMASs are restarted the required definitions are created automatically during the CMAS startup.

Note:
With MRO connections, this can result in a transient error (message DFHIR3788, return code X'68') if the connection has not yet been created on the remote CMAS. The error should resolve itself automatically once the connection has been created.
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1.
You can change the context only if the CASs CASSYS1 and CASSYS2 are connected. If they are not, you must start a second CICSPlex® SM session via CASSYS2.

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