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

Even, Roni roni.even at polycom.co.il
Tue May 22 16:55:40 EDT 2007


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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