CICS TCP/IP client and server processing

TCP/IP also supports client and server processing, where processes are either:

Servers that provide a particular service and respond to requests for that service
Clients that initiate the requests to the servers

With CICS® TCP/IP, remote client systems can initiate communications with CICS and cause a CICS transaction to start. It is anticipated that this is the most common mode of operation. Alternatively, the remote system can act as a server with CICS initiating the conversation.