comments on AVD 2253 from Raleigh

Paul E. Jones paulej at PACKETIZER.COM
Thu Sep 26 16:33:34 EDT 2002


Roni,

I can't recall exactly what the definition of "source" was, but I would
agree it should be stated clearly.  In any case, the word "source" is akin
(if not the same) as "source" in RFC 1889.  Essentially, a "source" might be
a microphone or a DSP that's converting audio into packetized media, etc.

Paul

----- Original Message -----
From: "Even, Roni" <roni.even at polycom.co.il>
To: "'Paul E. Jones'" <paulej at packetizer.com>; "Even, Roni"
<roni.even at polycom.co.il>; <ITU-SG16 at echo.jf.INTEL.COM>
Cc: "Martin Euchner" <Martin.Euchner at icn.siemens.de>
Sent: Thursday, September 26, 2002 3:53 AM
Subject: RE: comments on AVD 2253 from Raleigh


> Paul,
> Single source is not a good definition, is it an a same IP address or is
it
> the same encoder
> Roni
>
> > -----Original Message-----
> > From: Paul E. Jones [mailto:paulej at packetizer.com]
> > Sent: Thursday, September 26, 2002 6:56 AM
> > To: Even, Roni; ITU-SG16 at echo.jf.INTEL.COM
> > Cc: Martin Euchner
> > Subject: Re: comments on AVD 2253 from Raleigh
> >
> >
> > Roni,
> >
> > The current definition, which was drafted by Terry Anderson,
> > is pretty clear
> > that multiple payload streams must carry data from a single
> > "source", I
> > believe.  Have a look at AVD 2257.
> >
> > Paul
> >
> > ----- Original Message -----
> > From: "Even, Roni" <roni.even at polycom.co.il>
> > To: "'Paul E. Jones'" <paulej at packetizer.com>; "Even, Roni"
> > <roni.even at polycom.co.il>; <ITU-SG16 at echo.jf.INTEL.COM>
> > Cc: "Martin Euchner" <Martin.Euchner at icn.siemens.de>
> > Sent: Wednesday, September 18, 2002 4:06 AM
> > Subject: RE: comments on AVD 2253 from Raleigh
> >
> >
> > > Paul,
> > >
> > > I think that the requirement were to prevent audio and
> > video in the same
> > > stream on one side and to allow for multiple video or audio
> > in the same
> > > stream to be compatible with SIP capabilities and not only
> > for MOIP. So I
> > > think that there should be a text saying that in multiple
> > streams we do
> > not
> > > recommend audio and video in the same stream and to be able
> > to specify the
> > > packetization scheme for the multiple streams.
> > > Roni
> > >
> > > > -----Original Message-----
> > > > From: Paul E. Jones [mailto:paulej at packetizer.com]
> > > > Sent: Tuesday, September 17, 2002 7:52 PM
> > > > To: Even, Roni; ITU-SG16 at echo.jf.INTEL.COM
> > > > Cc: Martin Euchner
> > > > Subject: Re: comments on AVD 2253 from Raleigh
> > > >
> > > >
> > > > Roni,
> > > >
> > > > ,
> > > > > I have some concerns about the changes proposed in this AVD.
> > > > >
> > > > > 1. The AVD adds a new data type called
> > multiplepayloadstream that is
> > > > > intended to allow more then one payload in a stream.
> > > > According to the
> > > > ASN.1
> > > > > you can have different media types in the same logical
> > > > channel which is
> > > > not
> > > > > a good practice and would break a lot of implementations.
> > > >
> > > > We already have precedence for this, such as RFC 2833.  In
> > > > addition, this
> > > > feature would only be used if both sides advertise the
> > > > capabilities, so I do
> > > > not expect to see anything break.
> > > >
> > > > > 2. The data type in H.245 open logical channel describe the
> > > > media type but
> > > > > do not specify the RTP payload format used. There are cases
> > > > were there is
> > > > > more then one way to build the RTP stream for example in
> > > > H.263. In the OLC
> > > > > in H2250LogicalChannelParameters there is a RTPPayloadType
> > > > parameter that
> > > > > describe the RTP payload. If the AVD is used to describe
> > > > multiple streams
> > > > > there is no way to specify the packetization scheme used.
> > > >
> > > > This might be true.  Would it be possible to add those
> > parameters as
> > > > necessary in the future?  At the moment, the only use for
> > > > this capability at
> > > > the moment is for modem over IP, wherein every payload that
> > > > will be used is
> > > > understood based solely on the capability, I believe--
> > > > perhaps I'm wrong.
> > > > In any case, the important thing is to know whether the
> > > > syntax precludes the
> > > > specification of additional parameters.
> > > >
> > > > > 3. I think that the editor of H.235 will look to see if the
> > > > proposed AVD
> > > > > allows to specify and change a key for each payload that
> > > > can be used in
> > > > the
> > > > > logical channel. I am not an expert on H.235
> > > >
> > > > Most definitely.. I would certainly welcome comments and
> > > > input in the area
> > > > of security.
> > > >
> > > > Paul
> > > >
> > > >
> > >
> >
>

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