What is the importance of WS-Addressing in SOAP?

Question

I'm learning Web Services Addressing and SOAP, but I can't get the importance of WS-Addressing in SOAP. This is quoted from Wikipedia "standardized way of including message routing data within SOAP headers".

As far as I understand that message routing data for a WS is already included in the HTTP header, then why add it to the SOAP?

Answer 1

WS-Addressing is a higher level version of routing information, which does indeed duplicate some of the functionality available at the lower level in http.

You could argue it is not necessary, but SOAP is neutral to http: e.g. SOAP can work over a message queue without http.

As WS-Addressing is higher level, it provides for different response endpoints (fault vs. normal), a message id, and relationship to prior messages by id.