Re: [dispatch] Draft on Discarding Priority of RTP Video Packets

[Lijun Dong <[e-mail]>]

Hi Ron

As far as I understand the frame marking RTP header extension and your priority marking drafts, the meta-information from the video stream such as TID (temporal ID), LID (layer ID) for scalable streams, or 2 bits P field for either H.264 or scalable video codecs are included in this extension header.

The RTP header extension would not be visible to routers, because the RTP header is encapsulated by UDP and IP headers. Thus, routers when encountering congestion, would not apply dropping precedence for the packets from the same flow although they obviously differ in importance for decoding and user’s QoE.

My draft points out this priority difference at packet level, which I think you and many others already agree and support. And tries to find a way to let the routers utilize such information for dropping precedence when network congestion happens. I will have more discussions in the presentation whether mapping to DSCP is a good way to achieve this (honestly I do not think it is a very good way). I hope I would trigger your interest in considering other options and solutions.

Lijun

From: Ron Even <[e-mail]>
Date: Wednesday, July 13, 2022 at 12:19 AM
To: Lijun Dong <[e-mail]>
Cc: "[e-mail]" <[e-mail]>, Stuart Clayman <[e-mail]>, Muge Sayit <[e-mail]>
Subject: Re: [dispatch] Draft on Discarding Priority of RTP Video Packets

Hi,
I had a proposal in the past to use https://datatracker.ietf.org/doc/html/draft-ietf-avtext-framemarking-13<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Fdraft-ietf-avtext-framemarking-13&data=05%7C01%7Clijun.dong%40futurewei.com%7C1bcf58dbf9c34cf2425808da649ff5fa%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C1%7C637932935446599721%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=whCgSZiS5MclEhlMr7oPTzQiCPkeLikX7eqp61umP%2Bo%3D&reserved=0> for defining priority in the past. see https://datatracker.ietf.org/doc/html/draft-even-avtcore-priority-markings-03<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Fdraft-even-avtcore-priority-markings-03&data=05%7C01%7Clijun.dong%40futurewei.com%7C1bcf58dbf9c34cf2425808da649ff5fa%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C1%7C637932935446599721%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=zOWAm6F2rEPRVAMvRDhpz00kHvdb8wh8EYaAlfJm%2Btc%3D&reserved=0>.
Roni Even

On Wed, Jul 13, 2022 at 2:59 AM Lijun Dong <[e-mail]<mailto:[e-mail]>> wrote:
Hi dispatch:

I want to share my recently submitted draft on “Discarding Priority of RTP Video Packets”.

https://datatracker.ietf.org/doc/draft-dong-priority-rtp-packet/<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fdraft-dong-priority-rtp-packet%2F&data=05%7C01%7Clijun.dong%40futurewei.com%7C1bcf58dbf9c34cf2425808da649ff5fa%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C1%7C637932935446599721%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=jq%2BlyAeltH2vE1KkLGAiuAe3B59Ate9BNJeTj6woURI%3D&reserved=0>

It is observed that significance difference or discarding priority might exist among RTP packets which encapsulate video streaming data with the existing modern video codecs. So selectively dropping RTP packets according to their significances could be a complementary mechanism when dealing with network congestion and improve end user’s QoE. The draft proposes that the video source or edge node with media-awareness could perform mapping of RTP packet discarding priority carried in RTP NALU header to a DSCP value, such that the priority-based dropping could happen at the packet level when network congestion happens.

I look forward to your generous comments and suggestions.

Lijun



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