Response or conversational output available at restart

If, during session initiation, IMS has response mode or conversational output available to be sent or is in a sync-point response pending state, the bracket state manager reset and half-duplex flags within the IMS portion of the bind or bind response are set to in-brackets/SEND by IMS.

If IMS is in conversation mode but has no conversational output available or pending, these same bind or bind reply flags are set to in-brackets/RECEIVE, because input is required to continue the conversation. IMS does not accept a nonnegotiated BIND or negotiated BIND response indicating IMS to be in-brackets/RECEIVE when conversation or response mode output is available. Unless a sync point is pending from a previous session, the session is resumed and the STSN that is sent must receive a TEST POSITIVE reply to the SET AND TEST option in order for processing to continue.

When IMS is in conversation or response mode and receives a nonnegotiated BIND or a response to a negotiated BIND indicating between-brackets, IMS attempts to terminate the conversation or response mode. This termination is just like that which occurs if end-bracket is received on an FMH7 or LUSTATUS while IMS is in conversation or response mode during normal data flow active state (after SDT).

Conversation and response mode termination is only assured when the output reply message is available to be sent or the half session is waiting for the next conversational input. Therefore, IMS restricts attempts to terminate conversation or response mode by binding between-brackets when the output reply is available to be sent or no conversational input is required. If no output reply is available to be sent or no conversational input is required, a warning message is sent to the IMS master terminal operator with instructions to retry session initiation later.

If IMS receives a negotiated BIND indicating in-brackets/SEND and is not in conversation or response mode, a BIND response is sent indicating between-brackets. IMS sends LUSTATUS - NO-OP indicating end-bracket immediately after SDT when IMS is not in conversation or response mode and when receiving a non-negotiated BIND or negotiated BIND response indicating in-brackets/SEND. LUSTATUS - NO-OP is sent because transaction restart is not possible under these circumstances.

It is possible that IMS is left in-brackets/SEND after a BIND or BIND response, because a conversation or response mode output sync-point response is pending from the previous session. The output message might be dequeued if STSN processing indicates that the response was sent. In this case, an LUSTATUS - NO-OP indicating end-bracket is to be sent after SDT if the output message is a response mode reply. An LUSTATUS - NO-OP indicating change-direction is sent if the output message is a conversational reply, because input is required to continue the conversation.

If STSN indicates that the conversation or response mode message was not acknowledged, IMS again places the message in a sync-point response-pending state as if it had been sent with change-direction and as if it had requested an exception sync-point response. Any normal flow reply is then considered implicit acknowledgment of the pending output message and causes it to be dequeued by IMS even if the reply was an LUSTATUS - Abort or an ATTACH ATTDPN=SYSMSG. These replies indicate additional error conditions associated with the message's scheduling or execution. Had the session not failed, these error conditions would have been reflected by an exception response to the sync-point request rather than the LUSTATUS - Abort or ATTACH ATTDPN=SYSMSG. Depending on the sense code used, the exception response might have caused the message to be returned to the message queue (backed out) for retransmission rather than dequeued (committed) as occurs for LUSTATUS - Abort or ATTACH ATTDPN=SYSMSG resulting when both a session and an application failure occur together.