H.323/VoIP QoS

Roy, Radhika R, ALCOO rrroy at ATT.COM
Wed Mar 3 18:22:50 EST 1999

Hi Scott:

I guess that H.323 is a transport independent multimedia (audio, video,
and/or data) application. That is, H.323 can be transferred over any packet
network (e.g., IP, ATM, etc). So, one of the most important aspects of H.323
is to define signaling messages that will carry the QOS information at the
H.323 application level. H.323 will then signal the underlying transport
network to support the appropriate QOS.

I think that SG16 will limit their multimedia QOS activities at the H.323
application layer.

Now how this H.323 application level QOS information will be implemented
over a specific network layer can be implementation specific.

For example, if it is an Internet/IP network, IETF's DiffServ, RSVP,
intserv, and other QOS related services can be used by H.323's application
level QOS signaling messages.

Similarly, ATM network's QOS related services can also be used by the
H.323's application level signaling messages.

My view is that H.323's application level QOS work is intended to complement
all QOS related works that are being carried out at the lower "network layer
(e.g., IP/Internet, ATM, etc.)" in all standard bodies/forums (e.g., IETF,
ATM Forum, T1A1, TIPHON, IMTC, MSAF, etc.).

I do agree with you that no work should be undertaken that becomes counter
productive with respect to on-going works of IETF, ATM Forum, T1A1, TIPHON,
IMTC, MSAF, and other standard bodies/forums.

My view is that only complementary solutions should be considered.

With respect to H.323 QOS activity group's membership (per Joon Maeng's
email), I am not sure what actually it means. I thought that it might be a
part of the activities of SG16 to address QOS related issues at the H.323
application layer. Joon Maeng may elaborate more on that.


> -----Original Message-----
> From: Scott Bradner [SMTP:sob at HARVARD.EDU]
> Sent: Wednesday, March 03, 1999 4:52 PM
> Subject:      Re: H.323/VoIP QoS
> I do hope that you-all take a look at what is going on in the IETF
> before going off to invent a different QoS for IP technology - SG16
> doing that sort of thing would seem to be quite counter productive
> I would suggest that people interested in IP QoS get on the IETF mailing
> lists
> (diffserv, RSVP, and intserv - see www.ietf.org under working
> groups to find out how)
> Scott
> ----
> From ITU-SG16 at mailbag.cps.intel.com  Wed Mar  3 12:55:07 1999
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> Date:         Wed, 3 Mar 1999 12:41:50 -0500
> Reply-To: Mailing list for parties associated with ITU-T Study Group 16
>               <ITU-SG16 at mailbag.cps.intel.com>
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>               <ITU-SG16 at mailbag.cps.intel.com>
> From: "Roy, Radhika R, ALCOO" <rrroy at ATT.COM>
> Subject:      Re: H.323/VoIP QoS
> To: ITU-SG16 at mailbag.cps.intel.com
> Hi Everyone:
> I support this effort. In fact, Maeng and I had a very brief talk in the
> last Monterey meeting related to the QOS aspects of H.323. Recent AT&T,
> VTEL, and TIPHON contributions reflect many aspects of H.323/VoIP QOS.
> I also got encouraging responses when we talked about QOS related issues
> to
> many other companies. I guess that all of us would be benefited if the
> H.323/VoIP QOS aspects are satisfactorily addressed.
> Hope that the QOS activity group will be formed.
> Thanks,
> Radhika R. Roy
> AT&T
> (732) 420 1580
> rrroy at att.com
> > -----Original Message-----
> > From: Joon Maeng [SMTP:Joon_Maeng at VTEL.COM]
> > Sent: Wednesday, March 03, 1999 11:40 AM
> > Subject:      H.323/VoIP QoS
> >
> > Greetings!  My name is Joon Maeng.  I work for VTEL Corp in USA. I've
> > talked to
> > several companies while I was attending ITU and IETF meetings about
> > establishing
> > an ad-hoc group to address QoS (Quality of Service) issues in
> > REAL-TIME TRAFFICS in the packet switched network, especially in the IP
> > network.
> > I was very encouraged by responses from those companies.  Most of them
> > agreed
> > that lack of QoS support for real-time traffics  was one of major
> barriers
> > in
> > deploying H.323/VoIP products and  the H.323 industry would benefit by
> > having a
> > QoS activity group.  I would like to ask if your company would be
> > interested in
> > the activities described in the following:
> >
> > Proposed name of the group: H.323/VoIP QoS Activity Group.
> >
> > Motivation:  ITU defined a good conference standard, H.323, for the
> packet
> > network.  IETF is actively defining QoS standards for the IP network.
> The
> > deployment of H.323/VoIP products has been slow partially due to lack of
> > QoS
> > supports in current IP network.  The H.323/VoIP industry shall work
> > together to
> > access the issues and provide solutions for the users.
> >
> > Proposed charter of the group:
> > - Assess QoS issues in transporting real-time traffics (calls with
> > long-duration
> > compared to web-access) in the IP network,
> > - Find the solutions to resolve issues,
> > - Execute solutions via various processes such as building consensus on
> > various
> > QoS solutions among participants,
> >   submitting recommendations to standardization bodies if needed, and
> > facilitating inter-operablity testing between QoS standards and
> > application
> >   standards,
> > - and education,  promotion, etc.
> >
> > I would expect the final charter and the structure of the group will be
> > determined by the participants and their interests.    I would say that
> > everything is open at this time except that the industry shall look at
> the
> > QoS
> > issues seriously for real-time traffics.  I'd like to clarify that the
> > proposed
> > group is not a group to standardize the QoS.  It is a group or a forum
> > that is
> > interested in helping and promoting the real-time QoS for H.323/VoIP
> > industry
> > through various methods (to be determined).   I plan to set up an email
> > reflector for the initial discussions among participants and decide the
> > following steps based on the discussions. Please email me (joon_maeng@
> > vtel.com)
> > if you and your company would be interested in joining the initial talks
> > via
> > email reflector.   Your comments and suggestions will be greatly
> > appreciated.
> > Regards,
> > Joon

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