W3C home > Mailing lists > Public > public-ws-addressing@w3.org > June 2005

RE: Another go at lc75 and lc88 language (correction)

From: <paul.downey@bt.com>
Date: Tue, 7 Jun 2005 14:12:22 +0100
Message-ID: <2B7789AAED12954AAD214AEAC13ACCEF2709E39E@i2km02-ukbr.domain1.systemhost.net>
To: <tom@coastin.com>, <mark.little@arjuna.com>
Cc: <rsalz@datapower.com>, <public-ws-addressing@w3.org>

Tom

> I guess what I am seeing in this discussion is that the requirements for 
> wsa:messageId are not clear.

I don't see that at all. I see we have messageId for correlation, 
though I heard during the discussion in Berlin several potential
use-cases enabled by having a mandatory messageId. These included,
but were by no means limited to, transport independent message
correlation, logging and auditing by a transparent proxy observing
messages being exchanged, and elimination of duplicate messages.

> If it is intended to be a general purpose message id for use in wsa 
> message correlation as well as for other uses, then
> we might want to include the uid,integer pair.

I don't see how that follows at all. The introduction of integers 
implies to me you are thinking about some kind of windowing protocol 
where messages may be collated, missing messages may be identified 
and requested to be retransmitted within a range of messages. Possibly
even that the sequence number will roll-over and be reused.

That goes way, way beyond addressing, and isn't something we should
be following at all. From a procedural POV, i'm puzzled as to
what LC issue introducing such complexity and restriction
on the format of messageId would resolve.

> However, if it is just for use in ws addressing correlation, then 
> a URI would suffice, with no semantics on its contents.

I'm OK with a URI, but don't follow the reasoning.

> With a clarification on such a restricted use, it should only be 
> required when the reply to is present with a non anonymous value.

No. I disagree. That's making matters more complex and dependent
upon the binding for a single hop, rendering messagId less useful in 
end to end message passing scenarios where the message passes over
HTTP and then another transport such as Email/MQ.

> Other ws specs which need further semantics would be required to define 
> their own identity elements.  

Possibly, possibly not. It seems to me that making messageId 
mandatory and unique will make it more attractive for other
specs to layer upon it for identifying a unique message. 

> This has the advantage of allowing their 
> use when ws addressing is not being used.

That's their business.

Paul
Received on Tuesday, 7 June 2005 13:12:30 GMT

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