Subject: [tsvwg] RFC 4594 update: Hi-Res video class - open issue

From: "Black, David" <[email-masked]>
Date: Fri, 15 Mar 2013 14:29:00 -0400

This is about the other RFC 4594 update topic discussed yesterday
in Orlando.

The RFC 4594 update draft proposes to introduce a new diffserv
class for (high-resolution) telepresence video.  That new class
would be split out of the Multimedia Conferencing class.  FWIW,
that Multimedia Conferencing is also the source out off which the
new Video (Conferencing) class for interactive video will be split
(the WG already has rough consensus on the need for this new
Video class).

Here's the relevant slide content from Orlando (slide 1 from the
slide deck on Diffserv Service Class Questions):

	"Hi-Res" NEW 
		- For video and audio/video conferencing
		- Created for policy-based treatment different than "Video"

	Question #1: Is this new class needed?

The sense of the room was not clearly "Yes" - for that reason,
questions #2 and #3 in the slides were not asked in Orlando.
I heard considerably more of a hum for "No" than "Yes" and a
similar level of hum for "Not sure" as for "Yes".

Please comment on the need (or lack thereof) for this new class -
this decision starts from a default to not add the new class:

- The new Hi-Res class will only be added if there is good WG
	rough consensus that it is needed.
- Otherwise the class will not be added, even if the WG does not
	reach rough consensus that the new class is not needed.

Please limit discussion to the need or lack thereof for this new
Hi-Res class, and in particular please do not include the proposed
changes to CS4 and CS5 usage at this time - if the new class is to
be added, then whether to do that via changes to usage of CS4 and
CS5 will be opened up as a separate topic.

Thanks,
--David (tsvwg WG co-chair)
----------------------------------------------------
David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
[email-masked]        Mobile: +1 (978) 394-7754
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From: Joe Touch <[email-masked]>
Date: Fri, 15 Mar 2013 16:05:27 -0700

Hi, David,

One general assumption I have for diffsrv classes is that they should 
describe a service, not an application.

How does this service differ from that for conferencing (i.e., roughly 
constant bitrate, lossy allowed, low latency)?

Joe

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From: Brian E Carpenter <[email-masked]>
Date: Sat, 16 Mar 2013 07:51:20 +0000

> describe a service, not an application.

Not only that; they need to correspond 1:1 to a well defined PHB.

> constant bitrate, lossy allowed, low latency)?

And why does it need a new PHB, or a separate set of parameters
for an existing PHB?

   Brian

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From: <[email-masked]>
Date: Mon, 18 Mar 2013 12:56:03 +0100

Joe, Brian,

thanks, your questions are the ones I have too.

Regards,

Rüdiger

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Brian E Carpenter
Sent: Saturday, March 16, 2013 8:51 AM
To: Joe Touch
Cc: [email-masked]
Subject: Re: [tsvwg] RFC 4594 update: Hi-Res video class - open issue

   Brian

---

From: Dan Wing <[email-masked]>
Date: Mon, 18 Mar 2013 12:44:10 -0700

On Mar 15, 2013, at 4:05 PM, Joe Touch <[email-masked]> wrote:

> Hi, David,
> 
> One general assumption I have for diffsrv classes is that they should describe a service, not an application.

Agreed.

> How does this service differ from that for conferencing (i.e., roughly constant bitrate, lossy allowed, low latency)?

And, how will today's "high resolution" (1080i) compare with tomorrow's "high resolution" (4K, 8K), and more importantly, with the needs of the codecs used in the future and their tolerance to delay, loss, and jitter.

-d

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From: "Eggert, Lars" <[email-masked]>
Date: Tue, 19 Mar 2013 14:25:17 +0000

> 	Question #1: Is this new class needed?

As I said in the room in Orlando, I think it's a slippery slope if we start assigning codepoints to classes that are distinguished from others only by policy or preference and not intrinsically. So no, I don't think we want to do this.

(And you can already prioritize these video flows over other video flows by five-tuple, if you have to.)

Lars

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From: "Black, David" <[email-masked]>
Date: Fri, 29 Mar 2013 18:49:51 -0400

Between discussion in the room and on the list, it is clear
that the WG does not have rough consensus that the new "Hi-Res"
class is needed.  I believe that the WG has actually reached
rough consensus that the this new class is not needed.

> 	reach rough consensus that the new class is not needed.

Therefore, the new Hi-Res class should be removed from the next
version of the RFC 4594 update draft.

Moving on, I also wrote:

> in particular please do not include the proposed

The decision to not add the new "Hi-Res" class suggests that the RFC
4594 update draft should be revised to restore the recommended uses
of CS4 and CS5 to those in RFC 4594, but I am interested in hearing
further input and comments on this topic.

Thanks,
--David (tsvwg WG chair)

> From: [email-masked] [mailto:[email-masked]] On Behalf Of
> Black, David
> Sent: Friday, March 15, 2013 2:29 PM
> To: [email-masked]
> Subject: [tsvwg] RFC 4594 update: Hi-Res video class - open issue
>