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@lists.packetizer.com [mailto:itu-sg16-bounces@lists.packetizer.com]
On Behalf Of
Sent: Tuesday, May 22, 2007 11:36
PM
To: 'Gary Sullivan';
itu-sg16@lists.packetizer.com
Subject: Re: [itu-sg16] Instant
Messaging in H.323 & Common AlertingProtocol(CAP)
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@windows.microsoft.com]
Sent: Tuesday, May 22, 2007 4:14
PM
To:
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@lists.packetizer.com [mailto:itu-sg16-bounces@lists.packetizer.com]
On Behalf Of
Sent: Monday, May 21, 2007 9:23 PM
To: itu-sg16@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