Changing the target CICS region

The communications area passed to the dynamic routing program initially contains the system identifier (sysid) and netname of the default CICS® region to which the link request is to be routed. These are derived from the value of the REMOTESYSTEM option of the installed program definition. If REMOTESYSTEM is not specified, or there is no program definition, the sysid and netname passed are those of the local CICS region.

The dynamic routing program can change the sysid and netname. If it does so when it is invoked for route selection, the region to which the link request is routed is determined as follows:
  • The NETNAME and the SYSID are not changed.

    CICS tries to route to the SYSID as originally specified in the communications area.

  • The NETNAME is not changed, but the SYSID is changed.

    CICS updates the communications area with the NETNAME corresponding to the new SYSID, and tries to route the request to the new SYSID.

  • The NETNAME is changed, but the SYSID is not changed.

    CICS updates the communications area with a SYSID corresponding to the new NETNAME, and tries to route the request to the new SYSID.

  • The NETNAME is changed and the SYSID is changed.

    CICS overwrites the communications area with a SYSID corresponding to the new NETNAME, and tries to route the request to that new SYSID.

If the REMOTESYSTEM option of the program definition names a remote region, the routing program cannot route the request locally.

You can route DPL requests over both IPIC and ISC over SNA connections. If there is both an IPIC connection and an ISC over SNA connection to the selected target region, and both are named the same, the IPIC connection takes precedence. That is, if remote SYSID CICB is defined by both an IPCONN definition and a CONNECTION definition, CICS uses the IPCONN connection.

If the NETNAME specified is invalid, or cannot be found, SYSIDERR is returned to the dynamic routing program, which may deal with the error by returning a different SYSID or NETNAME. See If an error occurs in route selection.

If the routing program changes the SYSID or NETNAME when it is invoked for notification, the changes have no effect.