Sync/Async HTTP bindings

["Dave Ingham" <dave.ingham@arjuna.com>]

Following up on my action point from the last teleconference, here are
proposed definitions for WS-RM Synchronous and Asynchronous HTTP
bindings. Thanks to Sunil for comments and suggestions.

Synchronous SOAP HTTP binding:
We say that a synchronous SOAP HTTP binding is in use if the outbound
Reliable Message is sent in the HTTP POST request and the Acknowledgment
Message is contained in the corresponding HTTP response message. We
refer to this binding as "synchronous" in order to imply the WS-RM
exchange inherits the blocking behaviour of the HTTP exchange.

Asynchronous SOAP HTTP binding:
We say that an asynchronous SOAP HTTP binding is in use if the
Acknowledgement Message is sent in a separate HTTP POST request/response
exchange from the outbound Reliable Message. We refer to this HTTP
binding as "asynchronous" in order to emphasize that the WS-RM message
exchanges are not tied to the blocking request/response behaviour of the
HTTP transport. Two alternate usage patterns are possible. We say that
the "callback" pattern is being used if the Acknowledgement Message is
contained in the HTTP POST request of a second HTTP exchange operating
in the opposite direction to the one containing the outbound Reliable
Message. We say that the "polling" pattern is being used if a second
HTTP POST request is issued in the same direction as the one containing
the outbound Reliable Message to act as a request for acknowledgement.
The Acknowledgement Message is contained in the HTTP response to this
request. This polling pattern is expected to be used in situations where
it is inappropriate for the sender of reliable messages to receive HTTP
requests.

Any comments?

Best regards,

Dave.