You are advised to use MRO or APPC links for CICS®-to-CICS communication.
LUTYPE6.1 links are necessary for intersystem communication between CICS and any system, such as IMS™, that supports LUTYPE6.1 protocols but does not fully support APPC.
You must not have an LUTYPE6.1 and an APPC connection installed at the same time between an LU-LU pair.
A DEFINE CONNECTION is always required to define the remote system on an LUTYPE6.1 link. The sessions, however, can be defined in either of the following ways: