RE: [ws-rx] NEW ISSUE: anonymous AcksTo

["Vikas Deolaliker" <vikas@sonoasystems.com>]

I am not sure it is a dependency on WS-Addressing but rather an explicit
admission by that specification that should the source endpoint use
anonymous IRI, it is the responsibility of the transport binding or the
specification that defines that transport binding to provide a channel for
acks. In case of HTTP, it happens to be the reply to an HTTP Get/Put, but it
could be different for other transport say SMTP.  

Regardless that clarification could be made explicit in WS-Rx, I think. 

Vikas 



-----Original Message-----
From: Lei Jin [mailto:ljin@bea.com] 
Sent: Monday, July 11, 2005 12:19 PM
To: ws-rx@lists.oasis-open.org
Subject: [ws-rx] NEW ISSUE: anonymous AcksTo

I have the impression after talking to a few people that there is the
implicit assumption (though not specifically called out) in the spec
that if the AcksTo EPR is set to use the anonymous IRI, then all
subsequent acknowledgements for that reliable sequence will be sent back
synchronously on the http response path of either the application
message or an ack request message.

I think that is not a good idea.  First of all, we are saying that even
if my application message is one way (or asynchronous), I might still
receive something back on the http response(the WS-RX ack).  Nothing
really precludes this usage, but we are introducing unnecessary
dependency between WS-RX (acknowledgement messages) and WS-Addressing
(normal MEP).  For example, if I have an intermediary on the server side
that takes an incoming message, looks at the reply-to address (or
message MEP), and decides to close http connection if it's a oneway or
asynchronous message, everything works fine.  Now, with WS-RX, it has to
know that "hmm, maybe I shouldn't close that connection if WS-RX is
involved and synchronous ack is used". 

Secondly, the paragraph below quoted from WS-Addressing spec says the
anonymous IRI shouldn't be used as the destination in any other
circumstances other than the destination for reply messages.  I don't
see acknowledgements as reply messages.

WS-Addressing defines the following well-known IRI for use by endpoints
that cannot have a stable, resolvable IRI:
"http://www.w3.org/2005/03/addressing/role/anonymous";  Requests whose
[reply endpoint], [source endpoint] and/or [fault endpoint] use this
address MUST provide some out-of-band mechanism for delivering replies
or faults (e.g. returning the reply on the same transport connection).
This mechanism may be a simple request/reply transport protocol (e.g.,
HTTP GET or POST). This IRI MAY be used as the [destination] for reply
messages and SHOULD NOT be used as the [destination] in other
circumstances.

Proposal 1:

Specifically call out that the AcksTo EPR should not use the anonymous
IRI.

-- One reason to use an anonymous IRI is so that the acknowledgement may
reach sending endpoints that may be sitting behind a NAT or firewall.
But we have to deal with the same problem with asynchronous response
messages anyway.

Proposal 2:

Specifically call out that an anonymous IRI in the AcksTo EPR would
indicate acknowledgement message will only be sent back in response to
ack request messages where the ack request message should be a
standalone synchronous invoke.

Flames?

Lei