Re: [xrblock] WGLC - draft-ietf-xrblock-rtcp-xr-jb-02.txt

Glen Zorn <> Fri, 14 December 2012 10:04 UTC

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Date: Fri, 14 Dec 2012 17:04:01 +0700
From: Glen Zorn <>
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Subject: Re: [xrblock] WGLC - draft-ietf-xrblock-rtcp-xr-jb-02.txt
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I have reviewed this draft and have some comments.

*Section 1.1*
"SSRC" should be expanded on first usage.

*Section 1.4*
I'm pretty sure that jitter cannot be "encountered", because it is a 
timing abberation, not a physical object.  Suggest using "introduced" 

The second sentence says:

    These metrics are used to measure how the jitter buffer behave as a 
result of the
    jitter and applicable to a range of RTP applications.

The English language usage needs to be cleaned up a bit, but more 
importantly the statement sees to contradict the first sentence of 
Section 3 which says

    This block describes the configuration and operating parameters of
    the jitter buffer in the receiver of the RTP end system or RTP mixer
    which sends the report.

How can both be correct?

Sorry, but I have no idea what the third sentence means.

*Section 3*
It would be a very good idea, I think, to make capitalization and 
terminology consistent throughout the document.  An example from this 
section: "Instances of this Metrics Block" in sentence one but "this 
metric block" elsewhere.

Sentence two says "Instances of this Metrics Block refer by SSRC to the 
separate auxiliary Measurement Information block  [RFC6776] which 
contains measurement intervals." but AFAICT the Measurement Information 
lock describes only one interval.  Suggest changing to "Instances of 
this metric block refer by SSRC to the separate auxiliary Measurement 
Information block [RFC6776] which describes the measurement interval in 

*Section 3.2*
The description of the "jitter buffer nominal delay" says that "It is 
calculated based on the time for packets spent in the jitter buffer."  
How is it calculated?

*Section 8*
s/Hideaki Yamada,Claire Bi,Colin Perkin/Hideaki Yamada, Claire Bi, Colin 
Perkins, Glen Zorn