Routing client requests in a two-tier (gateway-less) environment requires use of the Server Option socket handler (SYSH). The socket handler is a conversational transaction that matches client application procedure calls to Server Option RPCs, thereby enabling a client application to access the Server Option directly (in two-tier mode) without needing to route transactions through a gateway.
For each client application logged in to the Server Option, a socket handler transaction instance receives client requests and manages the connection between the client application and the Server Option. In addition, CICS activates the socket handler transaction instance to handle a transaction abend. An active socket handler instance terminates when its associated client application logs out.
