[Standards-JIG] VoIP Jabber

[Richard Dobson]

This sounds like the perfect solution for those that want true integrated 
voip in XMPP/Jabber.

+1

----- Original Message ----- 
From: "Jean-Louis Seguineau" <jean-louis.seguineau at laposte.net>
To: <standards-jig at jabber.org>
Sent: Wednesday, February 09, 2005 9:56 AM
Subject: Re: [Standards-JIG] VoIP Jabber


>
>
> -----Original Message-----
> From: standards-jig-bounces at jabber.org
> [mailto:standards-jig-bounces at jabber.org] On Behalf Of
> standards-jig-request at jabber.org
> Sent: Wednesday, February 09, 2005 12:36 AM
> Hi All,
>
> This is an interesting thread, and reading it, I would like to reflect on 
> a
> few things:
>
> - VOIP, or any multimedia communication, is about communication. Without a
> common communication standard no communication is possible. I believe the
> major advantage of POTS is that one can call anywhere in the world...
> Looking at facts, almost all the VOIP hard or soft phones that are
> increasingly becoming available use RTP as a transport for the voice. This
> is not likely to change, because it has been burnt into the silicon. Same
> for the new 3G wireless devices that are starting to appear. And RTP means
> UDP.
> In the end we have to decide if we want to communicate (and that implies
> using RTP as the de facto transport for the p2p voice channel) or if we 
> want
> to create yet another closed community.
> There are several RTP open source libraries in many programming language.
>
> - Beside the transport of the voice (or video), establishing, maintaining
> and updating an RTP communication session requires some sort of signaling
> between the parties involved in the session. It is not simply about
> exchanging the IP addresses that would be necessary to establish the RTP
> stream, but also passing information about the end points capabilities,
> updating session information on the fly (for things like call forwarding 
> or
> conferencing), etc... all these niceties that are available on a POTS. To
> handle the actual voice session negotiation, there is also an agreed IETF
> standard called SDP (SDP is described in RFC 2327).
> There are several RTP open source libraries in many programming language.
>
> SDP does not clearly define a binding to a particular transport, i.e. it
> does not tell how you get the SDP payload to be exchanged between parties.
> There is a certain fad nowadays to exchange SDP using SIP as a transport.
> But you can as well use SMTP or why not XMPP...
>
> Using XMPP to transport the information used to negotiate the voice (or
> other media) session makes perfect sense, because we would leverage the
> existing communication channel that exists between the parties to perform
> that negotiation. We would use existing standards to express the session
> particulars, and we would use a standard transport protocol for the voice.
> And if some in the Jabber community want to come up with a SIP transport, 
> it
> would be somewhat easy to convert a call signaling from XMPP to SIP or 
> H323
> to interact with another VOIP network...
>
>>From a practical stand point, all the nuts and bolts are already there. We
> can easily incorporate the SDP/RTP negotiation in a new JEP-0095 Stream
> Initiation profile, similar to this
>
> <iq type='set' id='offer1' to='receiver at domain/resource'
> from='sender at domain/resource'>
>    <si xmlns='http://jabber.org/protocol/si'  id='a0' 
> profile='xmpp:si:ms'>
>       <media xmlns='xmpp:si:ms'>
>          <sdp xmlns='urn:ietf:rfc:2327'>
>             v=0
>             o=sender at domain 98765432 IN IP4 192.168.1.1
>             s=Multimedia questions
>             e=sender at domain
>             p=+1-212-741-6653
>             c=IN IP4 192.168.1.1/127
>             t=3288361865 0
>             a=sendrecv
>             m=audio 7800 RTP/AVP 0
>         </sdp>
>      </media>
>   </si>
> <iq>
>
> I believe this approach makes the most at leveraging existing standards
> including our own JEPs to allow developers to start working on the first
> implementations. Using these standard also allow to re-use many of the
> existing code for RTP and SDP, nad better incorporate it into clients.
>
> Best regards
>
> Jean-Louis Seguineau
>
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