[standards-jig] VoIP and Jabber

CORVOYSIER David FTRD/DMI/REN david.corvoysier at rd.francetelecom.com
Wed Apr 2 09:39:00 UTC 2003

As mentioned in another post, I am currently working on a project that
aims at providing VoIP/Video conferencing in Jabber.

We are currently having internally a strong debate about the way we
integrate the signalling part in the application, that roughly
corresponds to the previous threads on VoIP and Jabber.

Basically we have two options:

1 - keep the client-server protocol full XMPP and provide a gateway that
maps TINS to SIP and/or H323 (SIP is the primary target actually)
2 - develop a client that understands both XMPP and SIP/H323 (maybe

This appears to me a bit like the Jabber versus Trillian approach to
interoperable IM (fat clients versus transports). The choice is not easy
because both solutions have pros and cons:

Solution 1 Pros:
- simpler client,
- allows rich conferencing,
- more "packaged" solution.

Solution 1 Cons:
- risk of reinventing the wheel,
- difficulty/cost of implementing the gateway, 
- no formal adoption of TINS by the jabber community,
- TINS out of the scope of the XMPP WG.

Solution 2 Pros:
- Can take advantage of existing client SIP/H323 stacks,
- easier to interface with existing voice networks

Solution 2 Cons:
- heavy-weight client,
- likely to require multiple servers if we want to interoperate with SIP
or H323 world,
- not easy to mix different conferencing modes,
- NAT traversal ?
- versionning nightmare to follow the evolutions of three protocols.

I personnaly would like to see the jabber community start debating about
the way to integrate VoIP and Video in Jabber, because I expect growing
conflicts between SIP, H323 and XMPP as protocols extends and overlaps.

At least, since my project involves XMPP, SIP and H323 implementers, and
since we tend to be led by our implementations to discuss this matter, I
am very interested in having as many advices as I can from external
people involved in each realm (XMPP/H323/SIP).

-----Message d'origine-----
De : Craig Southeren [mailto:craig_southeren at hotmail.com]
Envoye : mardi 1 avril 2003 15:32
A : standards-jig at jabber.org
Objet : [standards-jig] VoIP and Jabber

To all,

   As one of the co-authors of the OpenH323 project (used by many VoIP 
projects, including GnomeMeeting), and as someone who has just started 
getting into Jabber in a big way, I am interested in working with
parties to move ahead on the integration of VoIP functions into Jabber.

   I've seen some of the previous emails re VoIP on this list 
and those seem to be heading towards duplicating the signalling
functions of 
H.323 and SIP using the Jabber protocol. While this would be possible, I

really don't think this is the right approach. VoIP is a LOT more
than just exchanging IP addresses and port numbers: think about call 
deflection, conferences, integration with existing voice networks,
progress tones, out of band DTMF tones, and call routing. Trust me, you 
don't want to get into it if you can avoid it :)

  Jabber has the potential to be much more than just duplicating the 
signalling functions of H.323 or SIP. Being able to advertise a normal 
telephone number for voice calls using Jabber would be very useful. Or a
number, or integration with SMS messaging, and so on.

  Is there are a standard way for a Jabber user to advertise any voice
video related information via a Jabber server? That is, is there a
way for me to include a telephone number in my externally visible Jabber

information? Can I specify my cell phone number, or my landline number?
I specify the address and port of my H.323 phone or my SIP phone? Can I 
indicate that I can do audio and/or video? Can I select what users can
what information? I'd like this right now - is there a standard for

   I am also interested in starting an effort within the H.323 community
define a standard way for the H.323 protocol to interface to IMPP
and Jabber. This may require the definition of new messages and
within H.323 - if anyone is interested in this, then please contact me.

  The SIP community already seems to working on their own solution to
Rosenberg has his own strong opinions on this, and whilst OpenH323 is 
working to include the SIP protocol (via the Opal project), I will leave
specifics of how SIP handles this to others who have more time.

   I am already working on these kinds of ideas, and would be very 
interested in talking or emailing with others who would like to work on
also. Whilst I am a newbie as far as Jabber is concerned, I have lots of

experience in VoIP and would be happy to bring that to bear on the

  BTW: for those who do not know, OpenH323 can be found at 
http://www.openh323.org and runs on Linux, Windows, *BSD, and OSX (among


   Craig Southeren

P.S - sorry for the use of hotmail - my main work machine is down right
and I cannot access my normal email account until I get it running again

MSN Instant Messenger now available on Australian mobile phones. Go to  

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