Re: [xrblock] Fw: I-D Action: draft-ietf-xrblock-rtcp-xr-discard-05.txt

Qin Wu <> Wed, 25 July 2012 06:51 UTC

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From: Qin Wu <>
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Subject: Re: [xrblock] Fw: I-D Action: draft-ietf-xrblock-rtcp-xr-discard-05.txt
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Based on Alan's proposal to the open issue mentioed below, we like to add one new section after SDP signaling section as follows:
6. Consideration for duplicate packets discards

Early/ late discards are usually regarded as a symptom of PDV due to congestion (or route changes) however duplicate packets discards have quite different causes.

(a) A few duplicate packets can indicate some form of Layer 1/2 LAN problem. This would not need to be an accurate measure - more of a general barometer.

(b) If the number of duplicate packets is very high then this may be due to RTP replication - and if this is the case then you would want to compare the number of duplicate packets to the number of received packets in the same time interval. If the duplicate packet count is X% of the received packet count, this indicates that a (100-X)% packet loss rate is being "hidden" by the replicated packets, and  it is very useful to know the actual loss rate(useful to indicate that replication should be kept "on" and helpful to know that there are some network issues that need to be investigated).
Hope this can close the remaining issue. We will discuss this proposed new section in the Vancouver meeting but also good to listen to your opinion before the meeting.

-Qin WU
----- Original Message ----- 
From: "Qin Wu" <>
To: <>
Sent: Tuesday, July 10, 2012 8:19 PM
Subject: [xrblock] Fw: I-D Action: draft-ietf-xrblock-rtcp-xr-discard-05.txt

> On 10 July , 2012 8:02 PM, wrote:
>> A New Internet-Draft is available from the on-line Internet-Drafts directories.
>> This draft is a work item of the Metric Blocks for use with RTCP's Extended Report Framework Working Group of the IETF.
>> Title           : RTCP XR Report Block for Discard Count metric Reporting
>> Author(s)       : Geoff Hunt
>>                          Alan Clark
>>                          Glen Zorn
>>                          Qin Wu
>> Filename        : draft-ietf-xrblock-rtcp-xr-discard-05.txt
>> Pages           : 13
>> Date            : 2012-07-10
>> Abstract:
>>   This document defines an RTCP XR Report Block that allows the
>>   reporting of a simple discard count metric for use in a range of RTP
>>   applications.
>> The IETF datatracker status page for this draft is:
>> There's also a htmlized version available at:
>> A diff from previous version is available at:
> [Qin]: One update according to the comments received in the WGLC.
> The main change to previous version is based on the recent discussion and agreement on the list with Shida, 
> Dan, Alan, Varun and in the section 3.2, definition and description
> about Discard Type. Some text is added to clarify how to report each of discard type or combination of 3 discard types.
> One remaining issue is raised by Alan, which is about whether we should add some texts to explain 
> the causes of duplicated packets discards in the draft.
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