[itu-sg16] Instant Messaging in H.323 & Common AlertingProtocol(CAP)

Paul E. Jones paulej at packetizer.com
Tue May 22 18:17:46 EDT 2007


Francois,

 

That's precisely what Paul Reddy (Intel) had proposed back in 2000.  Doing
that increases the complexity for the user, as they then have to be logged
into two different networks.  It also means we need to define an interface
between the XMPP client and the H.323 endpoint.  In theory, it would work
quite well.  (I use XMPP and it impresses me how we are able to have a
completely federated IM system. it's probably one of the world's best-kept
secrets, in spite of Jabber's very hard work trying to enlighten the world.)

 

I have no objection to that if that's what we want to do to deliver IM
functionality, but if we do that then we definitely need to consider CAP
separately, as the requirement we have is to send CAP messages to H.323
devices.

 

So, do we want to reconsider XMPP/H.323 association?  You know, Jungle was
created precisely because marrying SIP and XMPP was viewed as complicated.
(Perhaps that and the fact that the SIP WG wanted to have native methods and
would consider no less.)

 

Paul

 

From: Francois Audet [mailto:audet at nortel.com] 
Sent: Tuesday, May 22, 2007 6:04 PM
To: Paul E. Jones; Even, Roni; Gary Sullivan; itu-sg16 at lists.packetizer.com
Subject: RE: [itu-sg16] Instant Messaging in H.323 & Common
AlertingProtocol(CAP)

 

Another appoach would be to use XMPP and/or SIMPLE directly (as a separate
session).

 

You would bootstrap the XMPP session from the H.323 session by each side
providing the URI for the IM.

 

There are a number of clients out there that use SIP for voice/video session
setup but XMPP for IM. The same could be done with H.323. 

 


  _____  


From: itu-sg16-bounces at lists.packetizer.com
[mailto:itu-sg16-bounces at lists.packetizer.com] On Behalf Of Paul E. Jones
Sent: Tuesday, May 22, 2007 14:48
To: 'Even, Roni'; 'Gary Sullivan'; itu-sg16 at lists.packetizer.com
Subject: Re: [itu-sg16] Instant Messaging in H.323 & Common
AlertingProtocol(CAP)

Roni,

 

I believe there is an interest in the market.  I've been asked many times
over the years, we've seen many proposals, etc., but inevitably somebody
kills every proposal before we are able to make any real progress.  I will
argue that, yes, we need IM within H.323.  Does it need to interoperate with
SIMPLE or XMPP?  Not directly: that's what an SBC can handle for us, just as
it does everything else.  Do we want to make it as interoperable as
possible?  No objections: we're not consenting text at this meeting and we
have time to work out issues.

 

The way I view it, we need something.  I've seen people doing things ranging
from using the user-data field to nonStandardData field, to H.460.x-style
extensions.  I'd prefer to start with something and then we solicit
contributions and comments against it.  I really want forward progress on
this long-standing open work item.

 

Paul

 

From: Even, Roni [mailto:roni.even at polycom.co.il] 
Sent: Tuesday, May 22, 2007 4:56 PM
To: Paul E. Jones; Gary Sullivan; itu-sg16 at lists.packetizer.com
Subject: RE: [itu-sg16] Instant Messaging in H.323 & Common
AlertingProtocol(CAP)

 

Paul,

I understand the request for emergency message protocol but I am wondering
if it will help to have it as part of a general H.323 IM protocol or as a
standalone solution. 

My concern is that we have not succeeded in defining a general IM protocol
for H.323 was probably because of lack of real market requirements and
trying to define it now may cause us to define an IM solution which is not
optimal ( and difficult to interact with XMPP and SIMPLE based IM solutions)
while the only real requirement is for the emergency message protocol.

Roni Even

 


  _____  


From: itu-sg16-bounces at lists.packetizer.com
[mailto:itu-sg16-bounces at lists.packetizer.com] On Behalf Of Paul E. Jones
Sent: Tuesday, May 22, 2007 11:36 PM
To: 'Gary Sullivan'; itu-sg16 at lists.packetizer.com
Subject: Re: [itu-sg16] Instant Messaging in H.323 & Common
AlertingProtocol(CAP)

 

Gary,

 

T.134 is an application protocol entity for sending text messages within the
context of a T.120 conference.  So, it's not usable within H.323.

 

T.140 is a character presentation format and is used by H.323 Annex G for
delivering real-time text.  However, real-time text and Instant Message are
not the same (so I'm getting closer to answering your question).

 

V.18 is a protocol for sending text over a PSTN circuit using modulated
signals (modem), so that's far away from what we're doing in H.323 (or IP
networks in general).

 

So what is the difference between H.323 Annex G (real-time text) and Instant
Messaging?  The difference is how messages are composed, transmitted, and
delivered.  With H.323 Annex G, characters are collected and transmitted as
they are entered by the user and then displayed on the remote device
"character at a time" (or as close to that as possible).  With Instant
Messaging (IM), entire sentences or paragraphs are entered and then
transmitted as a single message block.  The latter is what we see with MSN
Messenger, Yahoo Messenger, Sametime, Jabber / XMPP / Google Talk, AIM, and
other similar clients.

 

The desire that has been expressed since at least 2000 is to support some
form of IM in H.323.  We've had several proposals and nothing has moved
forward beyond the initial presentation (or at most the second meeting).  I
never understood why, but now we have a situation where we're being asked to
deliver what is essentially a "text message".  If we have an IM protocol in
place, it would become trivial to deliver that capability.  Thus, I'd like
to see hastened forward progress on the IM work we've been debating for so
many years.

 

I hope that helps. 

 

Paul

 

From: Gary Sullivan [mailto:garysull at windows.microsoft.com] 
Sent: Tuesday, May 22, 2007 4:14 PM
To: Paul E. Jones; itu-sg16 at lists.packetizer.com
Subject: RE: [itu-sg16] Instant Messaging in H.323 & Common Alerting
Protocol(CAP)

 

Paul et al,

 

What is the difference between "IM" and "text chat"?

 

And how do these efforts relate to the following?:

T.134 - Text chat in data conferencing

T.140 - Protocol for multimedia application text conversation
V.18 - Text telephony

Best Regards,

 

Gary Sullivan

 


  _____  


From: itu-sg16-bounces at lists.packetizer.com
[mailto:itu-sg16-bounces at lists.packetizer.com] On Behalf Of Paul E. Jones
Sent: Monday, May 21, 2007 9:23 PM
To: itu-sg16 at lists.packetizer.com
Subject: [itu-sg16] Instant Messaging in H.323 & Common Alerting
Protocol(CAP)

Folks,

 

We have debated the introduction of a method of sending IMs within H.323 for
years.  It's unfortunate, especially considering how the H.323
infrastructure so easily lends itself to such functionality.  There was a
renewed hope with some documents introduced during the Shenzhen meeting that
suggested a means of sending IM within the context of a call, as well as
outside the context of a call.

 

One of the other matters we were asked to consider within the context of
H.323 and H.248 is the transmission of emergency messages using a format
called the "Common Alerting Protocol".  During the Shenzhen meeting, we sent
a liaison to SG17 urging them to consider the creation of an ASN.1
specification that would more readily transport within H.323 networks.  I
can report that, not only did they do that, it has been put forward for
consent already.  The standard will be X.1303.

 

So, the next step is to define procedures for transporting X.1303 (CAP)
messages within H.323.  Initially, I considered creating an H.460.x
extension, but then I thought that a better solution might be to use
something like H.450.7 (Message Waiting Indicator).  But, as I thought about
this, perhaps the best way is to marry this with the Instant Messaging
proposals we've seen before.

 

If we were to standardize the ability to send instant messages within H.323,
both within and outside the context of a call, then it would be possible to
send X.1303 messages as an "instant message".  This does introduce a new
requirement, though, in that we ought to "tag" the type of message so that
it is properly treated.  Instant Messages might appear unprocessed on the
user's screen, whereas X.1303 messages must be decoded and formatted for
human readability.

 

So, I would like to draft a proposal for this upcoming SG16 meeting to do
precisely what I said: let's move forward on the work of sending IM messages
within H.323, adding a tag that indicates the type of message.  We can also
utilize the call priority procedures in H.460.4 in order to ensure that an
emergency CAP message gets higher priority through the network.

 

Does this sound reasonable and acceptable?  Do others have other proposals?

 

If it is acceptable, then I have a question of procedure.  The proposals for
instant messaging were not accepted as new work items for Q2, though they
were not rejected: the request was for further progress.  Unfortunately, the
contributor is not a member of the ITU, which leaves us in a difficult
situation.  As a possible means forward somebody might volunteer to submit
these documents as formal contributions to this SG16 meeting under their
company's name.  Is that agreeable and are there any volunteers?

 

Do you have another idea for how we can support X.1303 (CAP)?

 

Thanks,

Paul

 

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