Listener task, CIEP

The CIEP task is attached by SO domain when it receives data on the port specified in the IPECI TCPIPSERVICE. The CIEP transaction handles control flows directly, or attaches a mirror task to issue the ECI program link request.

The valid flows that may be received by CIEP are:
  • Attach FMH for CCIN INSTALL

    The initial flow from a client is an attach for the CCIN transaction to install the client. No attach is done as IE domain handles the installation processing internally.

  • Attach FMH for CCIN UNINSTALL

    A client can terminate its connection with CICS® by sending a CCIN UNINSTALL transaction request. No attach is done as IE domain handles the installation processing internally.

  • Attach FMH for some other transid, assumed to be a mirror
  • FMH7 indicating the client wants to abend a conversation.
  • Connection level PING request/reply
  • Conversation level PING request/reply
  • Connection status 01, last transmission from client (equivalent to UNINSTALL)
  • User data in extended conversation (Link request or SYNCPOINT RU)
All other flows are rejected by CIEP; conversation errors with an FMH7, control errors by closing the socket.

The different flows are distinguished by testing various fields in the flow headers, including the SNA format RH.