A logical unit of work (LUW) is a set of autonomous changes to a set of protected resources that move them from one consistent state to another in such a way that the unit of work appears atomic. This set of changes is the work that occurs between two syncpoints or synchronization points; this work must be executed together for correctness. If a failure occurs during the LUW, all the changes that are made are undone and the state is restored to that at the start of the LUW. An LUW is the Systems Network Architecture (SNA) equivalent of an CICS Toolkit transaction; however, several transactions can correspond to the same LUW.
An LUW identifier is unique across the SNA network, just as a Toolkit global transaction identifier (global tid) is unique throughout the CICS Toolkit Server. A Toolkit transaction identifier (tid) is local to the gateway server (there is no analogue in the SNA terminology).
You can list the transactions or LUWs active at the gateway server and query the gateway server for more information about individual LUWs.