The APPLID parameter specifies the z/OS® Communications Server application identifier for this CICS® region.
If CICS is running in a sysplex, its APPLID must be unique in the sysplex.
This parameter can be used also as the application identifier of this CICS region on IPIC connections.
When you define this CICS region to another CICS region, in an MRO or ISC over SNA CONNECTION definition you specify the APPLID using the NETNAME attribute; in an IPIC IPCONN definition you specify the APPLID using the APPLID attribute.
When sharing a DL/I database with a batch region, the APPLID is used by the batch region to identify the CICS region.
If the CICS region uses XRF, the form of the APPLID parameter is as follows:
When you define this XRF pair to another CICS region, in an MRO or ISC over SNA CONNECTION definition you specify the generic APPLID using the NETNAME attribute; in an IPIC IPCONN definition you specify the generic APPLID using the APPLID attribute.
When sharing a DL/I database with a batch region, this name is used by the batch region to identify the CICS region. CICS passes the generic applid to DBRC, because the alternate system does not sign on to DBRC until it has completed takeover.
Do not confuse the term generic applid with generic resource name. Generic APPLIDs apply only to CICS regions that use XRF. Generic resource names apply only to z/OS Communications Server generic resource groups.
The active and alternate CICS regions use the z/OS Communications Server MODIFY USERVAR command to set a user application name variable, so end users do not need to know which CICS region is active at any instant.