Subject: Genart last call review of draft-ietf-rmcat-video-traffic-model-06

From: Ines Robles <[email-masked]>
Date: Thu, 24 Jan 2019 12:09:55 -0800

Reviewer: Ines Robles
Review result: Ready

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair.  Please treat these comments just
like any other last call comments.

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Document: draft-ietf-rmcat-video-traffic-model-06
Reviewer: Ines Robles
Review Date: 2019-01-24
IETF LC End Date: 2019-01-28
IESG Telechat date: Not scheduled for a telechat

Summary:

I believe the draft is technically good. This document is well written and
clear to understand.

This document describes two reference video traffic models for evaluating RTP
congestion control algorithms.  The first model statistically characterizes the
behavior of a live video encoder in response to changing requests on target
video rate.  The second model is trace-driven, and emulates the output of
actual encoded video frame sizes from a high-resolution test sequence.  The
document describes also how both approaches can be combined into a hybrid model.

Additionally, The stand-alone traffic source module is available as an open
source implementation, which I think it is very nice. :)

I did not find issues. I have some minor questions/suggestions.

Major issues: Not found

Minor issues: Not found

Nits/editorial comments:

- Page 14: correponding -> corresponding

- steady state, sometimes appears as steady-state, it would be nice to unify
these terms.

Some Questions/suggestions:

1- In Figure 1, would it be correct to add an input as a self-loop arrow
indicating "dummy video frames"? (As previously was an input "raw video frames"
e.g. in version 4 )

2- Would it be correct to add in:

2.1- Page 14: "...ongoing, steady-state behavior of a video..." => "...ongoing,
steady-state behavior (fluctuation around a constant target rate) of a
video..."? [1]

2.2 - Page 8: "...is considered to be in a transient state...." => "...is
considered to be in a transient state (reaction to abrupt changes in target
rate)...."? [1]

[1] Based in
https://datatracker.ietf.org/meeting/101/materials/slides-101-rmcat-rmcat-video-traffic-model-00
- Slide 2

3- Would it be correct to add in the Figure 3 something like?:

- R_v > R_v_previous for transient state

- R_v <= R_v_previous for steady state

Thanks for this document,

Ines.