Re: [rmcat] [tsvwg] FW: Fwd: Submitted ID on delay vs. loss-only rate-adaptive for DiffServ

["Cheng-Jia Lai (chelai)" <[e-mail]>]

Same here... I feel it makes sense to create a new DSCP / CS4 for transport of video flows that have rate adaptive behaviors and/or intra-flow preferential drop priorities as indicated in the I-D. The service provided by the network may thus be considered new, i.e. different from what exists in AF4x, so IMHO, using a new or reusing CS4 service class adds clarity for the user applications.

Regards,
CJ


-----Original Message-----
From: [e-mail] [mailto:[e-mail]] On Behalf Of Michael Ramalho (mramalho)
Sent: Tuesday, July 16, 2013 6:36 AM
To: [e-mail]
Subject: [tsvwg] FW: [rmcat] Fwd: Submitted ID on delay vs. loss-only rate-adaptive for DiffServ

TSVWG Members,

I should have copied you on my email to the RMCAT mailer below.

I strongly support the creation of a new DSCP for transports in which their congestion control can adapt based on delay.

The current ID in support of this (http://www.ietf.org/internet-drafts/draft-polk-tsvwg-delay-vs-loss-ds-service-classes-00.txt ) is a work in progress, but a step in the right direction.

It is a given that the ability of the eventual RMCAT adaptation mechanisms to achieve low delay will be function of the other dominant traffic it is competing against. If the dominant competing traffic DEPENDS on loss, the RMCAT packets are held hostage to being delayed by the bottleneck queue delay maximum.

Thus, whenever possible, it will be preferable for RMCAT flows to compete with other congestion control transports that adapt on delay. Even this may not get us to the desired low-delay goals when a portion of the traffic has long RTTs (i.e., adaptation control loops that are long in time), or for links that have a highly-time varying capacity,  but it will help for a lot of common bottleneck topologies (e.g., slowly time-varying access bufferbloat).

It is my hope that this topic has some discussion time in the Berlin Transport WG (not the specific codepoint to be chosen, but rather the need for one).

Off Soapbox,

Michael Ramalho, Ph.D.

-----Original Message-----
From: Michael Ramalho (mramalho) 
Sent: Tuesday, July 16, 2013 9:06 AM
To: [e-mail]
Subject: RE: [rmcat] Fwd: [tsvwg] Submitted ID on delay vs. loss-only rate-adaptive for DiffServ

RMCAT Design Team,

The draft Lars references below is a formal request for a DSCP dedicated to "RMCAT-only (or other nice delay-based cc) traffic".

It will take a while to become socialized ... and we can progress our RMCAT work in the interim.

Michael Ramalho

-----Original Message-----
From: [e-mail] [mailto:[e-mail]] On Behalf Of Eggert, Lars
Sent: Tuesday, July 16, 2013 5:26 AM
To: WG WG
Cc: [e-mail]
Subject: [rmcat] Fwd: [tsvwg] Submitted ID on delay vs. loss-only rate-adaptive for DiffServ

Possibly of interest to RMCAT.

Begin forwarded message:

> From: James Polk <[e-mail]>
> Subject: [tsvwg] Submitted ID on delay vs. loss-only rate-adaptive for DiffServ
> Date: July 16, 2013 8:07:59 GMT+02:00
> To: <[e-mail]>
> 
> (as an author)
> 
> Toerless and I put together a draft about legacy rate-adaptation based only on loss vs. what RMCAT is looking to (for RTCWEB), which is based on delay and loss.  Here's the URL.
> 
> http://www.ietf.org/internet-drafts/draft-polk-tsvwg-delay-vs-loss-ds-service-classes-00.txt
> 
> It's more raw than we had in mind, but we believe this is necessary, based on implementation experience and what users and customers have in their networks, or are planning on having in their networks soon.
> 
> James & Toerless
>