Establishing connections between CICS TS for z/OS generic resources

Assume that you have two sysplexes, SYSPLEXL and SYSPLEXR, and that these contain the CICS® TS for z/OS® generic resource groups CICSL and CICSR, respectively.

About this task

This is illustrated by Figure 1. The steps involved in establishing connections between CICSL and CICSR are as follows:
  1. On each member of CICSL that is to initiate a connection to CICSR, statically define and install an APPC parallel-session connection in which the NETNAME is the generic resource name of CICSR—that is, define a generic resource name connection. Similarly, on each member of CICSR that is to initiate a connection to CICSL, statically define and install an APPC parallel-session connection in which the NETNAME is the generic resource name of CICSL.
    Note: You should not install any predefined connections other than generic resource name connections.

    The first attempt by any member of CICSL to acquire a connection to CICSR (or vice versa) uses a generic resource name connection.

  2. The CICSR member to which z/OS Communications Server sends the bind request searches for the generic resource name connection definition for CICSL. (If none exists, it autoinstalls one, subject to the normal rules for autoinstalling connections.)
  3. Subsequent connections that z/OS Communications Server happens to route to the same member of CICSR from different members of CICSL are autoinstalled on the CICSR member, using the CICSL member name as the NETNAME; that is, CICS autoinstalls member name connections. Similarly, subsequent connections to the same member of CICSL from different members of CICSR are autoinstalled on the CICSL member, using the CICSR member name as the NETNAME. The example in Example makes this clearer.

    The template used for autoinstalling these further connections can be any installed connection. CICS uses the generic resource name connection as the default template.

    If you decide to use a template other than the default for member name connections, remember that use of the sessions for these connections is initiated by the partner, so consider defining the MAXIMUM attribute of the SESSIONS resource with no contention winners. This attribute is described in Defining groups of APPC sessions. This is useful because the member name is not known to the applications in the system in which the member name connection is autoinstalled. They use the GR name for outbound requests. Therefore the member name connection is not used for outbound requests and so does not need to have any sessions defined as winners. By allowing the partner system to have all the sessions as winners, the overhead of bidding for loser sessions is avoided.

    A template is a normal installed connection defined with CONNECTION and SESSIONS resources that can be used solely as a template, or as a real connection. It is used as a model from which to autoinstall further connections.