WAS v8.5 > WebSphere applications > Web services > WS-ReliableMessagingWS-ReliableMessaging sequences
The WS-ReliableMessaging protocol relies on a "sequence" to manage the transmission of messages from reliable messaging source to reliable messaging destination. Each application message is given an identifier that identifies both the sequence and the message number (the position) within the sequence. Protocol flows are used to create sequences, to acknowledge messages and to terminate sequences.
We can think of a sequence as being a structured conversation between the reliable source and the reliable destination, through which each message in the sequence is passed reliably. A sequence also passes on the set of messages in the sequence in the order in which it receives them, so if it is important that messages are processed in a particular order - for example, if money must be credited to a bank account before a debit instruction is received to pay for a purchase - then those messages should be included in the same sequence.
The developer of a reliable web services application does not have to be aware of sequences, but the system administrator needs to monitor and manage sequences, as described in Detecting and fixing problems with WS-ReliableMessaging.
Related
Add assured delivery to web services through WS-ReliableMessaging
Detecting and fixing problems with WS-ReliableMessaging