Subject: [Sipping] Definition problem in RFC 4730 (KPML)

From: "Ilan Avner" <[email-masked]>
Date: Mon, 26 Mar 2007 07:05:14 +0200

Hi all, 
 
Section 4.2 - "Event Package Parameters" in RFC 4730 defines three
parameters that identify the subscription dialog.
The three parameters are "call-id", "local-tag" and "remote-tag".
The way to find a match between these header parameters and an existing
dialog is -
"The User Interface matches the local-tag against the to tag, the
remote-tag against the from tag, and the call-id against the Call-ID"
This definition is not clear enough, what I am referring to is the "tag"
matching, it is not clear what are the "to" and from" tag that the
"remote-tag" and "local-tag" from the event package parameters should be
checked against.
Dialog identifiers according to RFC 3261 are local and remote tag not
"to" and "from" tag.
I suppose the intention is that the "to" and "from" are the local and
remote tag respectfully (just like any other RFC\Draft" that uses SIP
header to match an existing dialog).
I tried to look at the examples in RFC 4730 in order to be sure that my
assumptions are correct and I became totally confused.
In the example, the ACK sent from the user that afterwards receives the
Subscribe is - 
 
   ACK sip:[email-masked] SIP/2.0
   Via: ...
   Max-Forwards: ...
   Route: ...
   From: <sip:[email-masked]>;tag=jfh21
   To: <sip:[email-masked]>;tag=onjwe2
   Call-ID: [email-masked]
   ...
 
The Subscribe event header in the subscribe request that arrives after
the ACK looks like -  
   Event: kpml ;remote-tag="sip:[email-masked];tag=jfh21"
               ;local-tag="sip:[email-masked];tag=onjwe2"
               ;call-id=[email-masked]
 
First, the event from the example contains not only the tags but all the
To\From headers, why?
Second, it looks like my assumption is wrong and that the "remote-tag"
is matched against the local tag (as defined in RFC 3261) and vise
versa. 
 
Can anybody make things clear?

Thanks

Ilan Avner 

Tel.  +972-3-9764513

Fax. +972-3-9764040

Mobile. +972-54-6608141

www.audiocodes.com <BLOCKED::http://www.audiocodes.com/> 

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