Subject: [Sip] 100rel incorporated into bis

From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 31 Dec 2001 10:52:09 -0500

Folks,

I have just finished incorporating 100rel into bis. As a result of this, 
a few things have changed which I wanted to bring up in advanced of 
publication of -06, which will include the text.

1. Reliability of provisional responses now only defined for
provisional responses to INVITE, although extension methods can
allow its usage. This is because PRACK needs to be sent within the
context of a dialog, and only responses to INVITE establish
dialogs (as far as bis is concerned).

2. Reliability of provisional responses which remain unacknowledged when 
the final response is sent, is no longer guarnateed. This is because the 
proxy transaction machines are specified such that provisional responses 
received after the final response are discarded. This has been the case 
since rfc2543. THerefore, in practice, I suspect that provisional 
responses would have never been reliably delivered after a final 
response was sent. If a UAS NEEDS for them to be delviered, it has to 
delay sending the final response. This is the biggest change.

3. Proxy behavior for reliable provisional responses no longer
defined separately; the spec states that it simply acts as a uas.

4. Scope of record-route headers for a reliable provisional
response is now the dialog rather than the particular request.

5.  Example PRACK flows were lost when incorporating into bis. I've 
asked Alan to add them into the call flows document.

6. Bis includes formal IANA registration of ``100rel'' option tag.

7. If a reliable provisional response gets no PRACK after 32*T1 seconds,
UAS sends 5xx to original request.

Please let me know asap if there are any comments or questions on these 
changes.

Thanks,
Jonathan R.

-- 
Jonathan D. Rosenberg, Ph.D.            72 Eagle Rock Avenue
Chief Scientist                         First Floor
dynamicsoft                             East Hanover, NJ 07936
[email-masked]                 FAX: (973) 952-5050
http://www.jdrosen.net                  PH:  (973) 952-5000
http://www.dynamicsoft.com

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