Subject: [dispatch] A comment on draft-kaplan-dispatch-b2bua-taxonomy-00

From: Gonzalo Camarillo <[email-masked]>
Date: Thu, 23 Feb 2012 12:42:06 +0200

Hi,

Section 3 of the draft says:

>    A typical centralized conference server, for example, is
>    not a B2BUA because it is the target UAS of multiple UACs, whereby
>    the UACs individually and independently initiate separate SIP
>    sessions to the central conference server.

You may want to clarify whether or not a conference server receiving an
INVITE and fanning out several INVITEs is a B2BUA (e.g., in a
push-to-talk call). The mechanism used to establish such a conference is
described in RFC 5366. It is the same mechanism as the one used to
invoke inline transcoding, and the document says inline transcoders are
B2BUAs. The difference is that in a conference, there is typically more
than one outgoing INVITE request. The document needs to clarify whether
for each of those legs, the conference server should be considered a B2BUA.

Also, you may want to include an Abstract and expand acronyms on their
first use.

Cheers,

Gonzalo

---

From: Paul Kyzivat <[email-masked]>
Date: Thu, 23 Feb 2012 12:13:50 -0500

IMO a conference focus is indeed a B2BUA. And there are other things 
with similar topology that aren't conference servers that have a similar 
signaling topology. Those B2BUAs that coordinate *2* sessions are simply 
an interesting special case of that.

For instance, a device that does what Splices was interested in, by 
splitting a voice+video session into separate sessions to a voice device 
and a video device, has similar topology and might be considered a 
special case of a conference server. (But I had people argue with me 
that it is not a conference server.)

And devices that coordinate more than two sessions can have many of the 
same roles that are described in this draft for the 1:1 case.

And then there is another hybrid: half UA, half B2BUA. E.g. a device 
that takes an audio+video session on one side, terminates the audio 
itself, but delegates the video to a separate device via a separate sip 
session.

	Thanks,
	Paul

On 2/23/12 5:42 AM, Gonzalo Camarillo wrote:
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