An MVS application can receive inbound LU 6.2 conversations directly (rather than through a transaction scheduler) by requesting the conversations through a process called registering. When it registers, the server application specifies, through the Register_For_Allocates service, which allocate requests it is to serve. Specifically, the server specifies the name of the local TP to which the client TP issues the allocate request, and the name of the LU that is targeted by the allocate request. An application that has successfully registered for allocate requests is considered to be an APPC/MVS server.

APPC/MVS places inbound allocate requests for which a server has registered on a structure called an allocate queue, on a first-in, first-out (FIFO) basis. APPC/MVS creates the allocate queue at the completion of the server's registration. APPC/MVS creates a separate allocate queue for every unique server registration. The server selects allocate requests from the allocate queue for subsequent processing.

A server can register for all the TP/LU pairs it has RACF authority to serve. Your installation's security administrator grants this authority through the APPCSERV general resource class of RACF (or a functionally equivalent security product).