Re: [xrblock] Proposed change to summary discard draft to address discard type issue

Hi,
----- Original Message ----- 
From: "Huangyihong (Rachel)" <rachel.huang@huawei.com>
To: "Glen Zorn" <glenzorn@gmail.com>
Cc: "xrblock" <xrblock@ietf.org>
Sent: Friday, September 21, 2012 2:48 PM
Subject: Re: [xrblock] Proposed change to summary discard draft to address discard type issue


> 
> 
> Best Regards!
> Rachel
> 
> 
> -----Original Message-----
> From: Glen Zorn [mailto:glenzorn@gmail.com] 
> Sent: Friday, September 21, 2012 2:26 PM
> To: Huangyihong (Rachel)
> Cc: Glen Zorn; xrblock
> Subject: Re: [xrblock] Proposed change to summary discard draft to address discard type issue
> 
> On 09/21/2012 12:55 PM, Huangyihong (Rachel) wrote:
> 
> ...
> 
>>
> >
> > In section 3.2.2, the description of Gap Discard Rate field, the
> > third paragraph.
> >
> > OLD TEXT:
> >
> > "
> >
> > where "number of packets discarded" is obtained from the RTCP XR
> >
> > Discard Block [DISCARD] and Packets Expected is calculated as the
> >
> > difference between "extended last sequence number" and "extended
> >
> > first sequence number" (Interval or Cumulative) provided in the
> >
> > Measurement Information block [MEASIDENT].
> >
> > "
> >
> > NEW TEXT:
> >
> > "
> >
> > where "number of packets discarded" is filled with number of packets
> > due to both
> >
> > early and late to be played outwhich is obtained from the RTCP XR
> >
> > Discard Block [DISCARD], and Packets Expected is calculated
> >
> > as the difference between "extended last sequence number" and
> > "extended
> >
> > first sequence number" (Interval or Cumulative) provided in the
> >
> > Measurement Information block [MEASIDENT].
> >
> > "
> >
> >
> > I would rewrite this as
> >
> > "where "number of packets discarded" is filled with the number of
> > packets discarded due to both early and late arrivalwhich is obtained
> > from the RTCP XRDiscard Block [DISCARD], and Packets Expected is
> > calculatedas the difference between "extended last sequence number"
> > and "extendedfirst sequence number" (Interval or Cumulative) provided
> > in The Measurement Information block [MEASIDENT]."
> >
> > But even so, it would imply that two instances of the RTCP XR Discard
> > Block are required, since a single Discard block can only report
> > discards due to either early or late arrival, not both. Is that your
> > intent? If so, then I would suggest making it explicit; if not, the
> > maybe just leave the text as it is.
> >
> > [Rachel]: I am okay with your proposed change. Also one instance is
> > sufficient since Discard draft supports reporting discards due to
> > both.
> 
> Yes but the statement that the '"number of packets discarded" is filled 
> with the number of
> packets discarded due to both early and late arrival which is obtained 
> from the RTCP XR Discard Block" is only true if a) the "Discard Type" 
> field in the Discard block is set to 11 or b) two instances of the 
> Discard block are present, one with the DT field set to 10 & the other 
> with the DT field set to 01.  Do you think that that should be mentioned?
> 
> [Rachel]: I got your point. How about changing the text to :
> "
>   where "number of packets discarded" is filled with the number of packets discarded 
>   due to both early and late arrival (e.g. the discard type field in the Discard block is 
>   set to 11) 

[Qin]: say "e.g." is not correct, it is better to rephrase as
(i.e.,Discard Type (DT) field set to 11 in the Discard block)

>which is obtained from the RTCP XR Discard Block [DISCARD], and Packets 
>   Expected is calculated as the difference between "extended last sequence number" 
>   and "extended first sequence number" (Interval or Cumulative) provided in The 
>   Measurement Information block [MEASIDENT].
> 
> "

> ...
> 
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