What is OTMA?
The IMS OTMA facility is a transaction-based connectionless client/server protocol that runs on IMS Version 5.1 or later. It functions as an interface for host-based communications servers accessing IMS TM applications through the z/OS Cross Systems Coupling Facility (XCF).
OTMA enables clients to connect to IMS to provide high performance for interactions between clients and IMS for a large network or large number of sessions. OTMA is implemented in a z/OS sysplex environment. Therefore, the domain of OTMA is restricted to the domain of XCF.