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

[Paul E. Jones]

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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