Re: [rtcweb] H.264 SVC and BUNDLE

Christer,
This is about the multiple session support in MST, look at the example in
section 7.3.3 of RFC6190, using the DDP grouping attribute from RFC5583.
I assume that you can solve it using RFC5576 ssrc-group but you will need to
define the DDP to be used also for ssrc-group

Roni

-----Original Message-----
From: rtcweb-bounces@ietf.org [mailto:rtcweb-bounces@ietf.org] On Behalf Of
Christer Holmberg
Sent: 30 August, 2012 9:51 AM
To: Dan Wing; public-webrtc@w3.org; rtcweb@ietf.org
Subject: Re: [rtcweb] H.264 SVC and BUNDLE

Hi Dan,

Thanks for the information!

The issue you raise is of course not related to BUNDLE, but to multiplexing
in general.

Regards,

Christer
________________________________________
From: Dan Wing [dwing@cisco.com]
Sent: Thursday, August 30, 2012 1:32 AM
To: Christer Holmberg; public-webrtc@w3.org; rtcweb@ietf.org
Subject: RE: [rtcweb] H.264 SVC and BUNDLE

> -----Original Message-----
> From: rtcweb-bounces@ietf.org [mailto:rtcweb-bounces@ietf.org] On 
> Behalf Of Christer Holmberg
> Sent: Wednesday, August 29, 2012 11:50 AM
> To: public-webrtc@w3.org; rtcweb@ietf.org
> Subject: [rtcweb] H.264 SVC and BUNDLE
>
> Hi,
>
> At the telco yesterday one of the Microsoft guys claimed that H.264 
> SVC does not work with BUNDLE, but he didn't have the details.
>
> Could someone please explain the reason why he/she doesn't think H.264 
> SVC work with BUNDLE?
>
> (Note, that if using the same port for the different codec layers is a 
> problem, then it's not a BUNDLE problem - it's a generic multiplexing
> problem.)

The general multiplexing of layers onto the same 5-tuple is a problem,
*if* we want the layers to have different DSCP values.  This is because we
cannot successfully and reliably set different DSCP values for packets
belonging to a 5-tuple over the Internet -- too many things rewrite the DSCP
field (to a different value) or simply clear the DSCP field.
This makes it impossible to restore the per-packet DSCP values later (e.g.,
using RSVP, or using any other better/stronger/faster signaling method).
If, however, each 5-tuple has its own DSCP value then that DSCP value could
be restored.

-d

> Thanks!
>
> Regards,
>
> Christer
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