NextExpectedMsgSeqNum too high

Imported from previous forum

[ original email was from Brien Oberstein - brien.oberstein@transacttools.net ]
Hi,

I’ve come across behavior in the 4.4 spec that could use some clarification.

In the "Logon Message NextExpectedMsgSeqNum Processing" section it specifies, "If [NextExpectedMsgSeqNum is] higher than the next-to-be-assigned sequence, send Logout to abort the session."

Presumably, if NextExpectedMsgSeqNum is higher than expected that represents a condition equivalent with the counterpart receiving a message with a lower than expected sequence number. The proper bahavior in that case is to immediately drop the connection without sending a Logout message.

Is this inconsistency intentional and if so could someone elaborate on what benefit the Logout provides? Typically, the Logout is used to do a clean shutdown that ensures gaps are filled prior to dropping the connection. In this case that’s probably counterproductive.

Thanks-
Brien