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

Re: on LC75

From: Tom Rutt <tom@coastin.com>
Date: Sun, 05 Jun 2005 17:06:18 +0200
Message-ID: <42A314EA.4040305@coastin.com>
To: Rich Salz <rsalz@datapower.com>
CC: Marc Hadley <Marc.Hadley@Sun.COM>, "public-ws-addressing@w3.org" <public-ws-addressing@w3.org>

Rich Salz wrote:

>>If we go this route I'd like to suggest we also add an optional
>>timestamp field. I've had several requests for WS-addressing to offer
>>support for such a thing separate from the message id itself.
>Can we point to wsu:Timestamp from OASIS WS-Security?
I had thought about this kind of extensibility, and one option would be 
to make the messageId complex type extensible in some way.

Before we get carried away, however, I think we should consider keeping 
the messageId type just having semantics of identity. 

WS-Reliability has a messageId complex type which has other information 
carried beyond idenity (e.g., first message insequence, last message in 
sequence), which was done for "efficiency" purposes.  However, this 
extra information is not necessary for the uniqueness
of identity.

One reason to have a message id which has a globalId with an integer 
index is for scalability purposes.  For examle, an endpoint could obtain 
its globalID URI at bootup time, using an integer counter of messages 
sent as the index.  This avoids generating a new globalID for each 
mesage, while keeping the messageId globally unique for each message sent.

Another reaons for an integer index is to enabline ordering of ids.  
Both WS reliability and WS- Reliable messaging use the pair as their 
identity.  They both also add semantics of sequence to the messageID 
(i.e., they specify that the index must increase by one each time a new 
message is sent, and that the global ID represents a particular 
messageSequence)  This sequence ID can be used for
control opeations pertainig to that sequence (eg. to terminate it).


However, in some cases the sequentiality might not be required.  Thus 
ws-addressing does not need to include the ordering
semantics for the integer index .

Now adding a timestamp is going beyond identity, and, for orthoganlity 
purposes, might be better to put somewhere else other than in the 
MessageId structure.

If we do not need extensibility, then  ws addressing can have a message 
ID structure as follows (which is backwards compatible with the last 
call messageId syntax):

    </xs:complexType><xs:complexType name="MessageIdType3">
            <xs:extension base="xs:anyURI">
                <xs:attribute name="index" type="xs:unsignedLong" 

Tom Rutt

>	/r$

Tom Rutt	email: tom@coastin.com; trutt@us.fujitsu.com
Tel: +1 732 801 5744          Fax: +1 732 774 5133
Received on Sunday, 5 June 2005 15:08:28 UTC

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