Drop Copy Sequence Reset - Dual Reset

In the event of an application failure, it may be necessary to use Sequence Reset - Dual Reset (tag 35-MsgType=4, tag 123-GapFillFlag=N) message to force synchronization of sequence numbers on the sending and receiving sides.

Keep these important points in mind:

• Do not use Sequence Reset - Dual Reset (35=4, 123=N) as a normal response to a Resend Request (35=2) message.

• Use a Sequence Reset - Dual Reset (35=4, 123=N) message ONLY to recover from a disaster situation that cannot be recovered via the use of Sequence Reset - Gap Fill.

• Using the Sequence Reset - Dual Reset (tag 35-MsgType=4) message may result in losing messages sent prior to the reset. The Sequence Reset - Dual Reset (tag 35-MsgType=4) message is identified as a Reset by setting tag 123-GapFillFlag to 'N' or leaving the tag out of the message.

• If the Sequence Reset - Dual Reset (35=4, 123=N) message is sent and is not in response to a Resend Request, tag 43-PossDupFlag should be set to 'N'.

• The Sequence Reset - Dual Reset (35=4, 123=N) message must increment the sequence number. A Sequence Reset - Dual Reset (35=4, 123=N) with a lower than expected sequence number logs the client system out.

• Tag 36-NewSeqNo of the Sequence Reset - Dual Reset (35=4, 123=N) message contains the sequence number of the next message to be transmitted by the receiving system. If the message is a Sequence Reset - Dual Reset (35=4, 123=N) message and the value in tag 36-NewSeqNo is equal to or higher than the expected sequence number, the tag 36-NewSeqNo is adopted as the new expected sequence number of the party that just processed the Sequence Reset - Dual Reset (35=4, 123=N) message.

• If the sequence number is lower than the expected, a Logout (35=5) message is sent.

• No acknowledgment is sent in response to the Sequence Reset - Dual Reset (35=4, 123=N) message; a successful reset will be indicated by the next value received in tag 34-MsgSeqNum.