gtpc1m2aTransmission Control Protocol/Internet Protocol

Deactivating Sockets

Use the ZTTCP INACTIVATE command, specifying the SOCKETS parameter to deactivate all of the sockets on a TPF host. When a TPF host processor is being deactivated, deactivate all sockets before cycling down below CRAS state.

When the TPF system is cycled below CRAS state, all sockets are cleaned up. For each connected TCP socket, a reset (RST) message is built to inform the remote end that the connection is being cleaned up. However, it is not guaranteed that the reset messages will be sent out before the TPF system cycles down. For this reason, enter the ZTTCP INACTIVATE command with the SOCKETS parameter specified before you cycle down your TPF system.

If the TPF system cleans up TCP sockets internally without notifying the remote partners (for example, during an unplanned TPF outage), one of two actions will occur:

  1. The remote end will send data while the TPF system is IPLing. No acknowledgments will be received, causing the remote end to detect the failure of the TPF system and clean up the sockets on the remote end.
  2. The TPF system is cycled up after the IPL and the remote end cleans up the socket when it sends the next message. The first message sent to the TPF system on any of these old sockets will cause a reset message to be sent to the remote end causing the remote end to clean up the old socket.

Enter the ZSOCK command with the INACT parameter specified to deactivate a specific socket or all sockets that have matching values for the selection criteria. The selection criteria can be any of the following:

See TPF Operations for more information about the ZSOCK command.