Re: [xrblock] WGLC for draft-ietf-xrblock-rtcp-xr-discardandxrblock-rtcp-xr-discard-rle-metrics

[Shida Schubert <[e-mail]>]

Qin;

 I was just simply asking a question that came up while I was reviewing the draft 
and I have no position on this. 

 So what you have currently is fine with me.  

 Regards
  Shida

On Jul 9, 2012, at 2:59 PM, Qin Wu wrote:

> Hi,Shida:
> Yes, currently we have four types. but the the 4 th type has been replaced with combine early, late and discarded due to duplication) in the current draft.
> You are right, if we combine discards due to duplication with either 1, or 2, we need to have two report blocks.
> My question, do we have the clear use case for such combinations you identify?
> 
> Regarding the assumption on whether it is used when duplicate packet arrives early or late,
> I think you should also consider one duplicated packet arrives on  time and how is discareded due to that it is duplicated packet.
> 
> Regards!
> -Qin
> ----- Original Message ----- 
> From: "Shida Schubert" <[e-mail]>
> To: "Varun Singh" <[e-mail]>
> Cc: "Alan Clark" <[e-mail]>; "Qin Wu" <[e-mail]>; "xrblock" <[e-mail]>
> Sent: Saturday, July 07, 2012 8:13 AM
> Subject: Re: [xrblock] WGLC for draft-ietf-xrblock-rtcp-xr-discardandxrblock-rtcp-xr-discard-rle-metrics
> 
> 
> 
> So my question was..
> 
> From what I can read, currently we have four types. 
> 
> 1. early ony
> 2. late only
> 3. both (late / early)
> 4. other (discarded to duplicate etc.)
> 
> According to my understanding based on Qin's response.
> 
> When there is an occurrence of 4 along with 1,2 or 3, you 
> need to have 2 report blocks.
> 
> 1 and 4, 2 and 4 or 3 and 4.. since we don't have a way 
> to express these combination currently.. 
> 
> This is based on my assumption that other is distinguished 
> from early or late Or is it used when duplicate packet arrives 
> early or late? 
> 
> Regards
>  Shida  
> 
> On Jul 6, 2012, at 8:34 PM, Varun Singh wrote:
> 
>> On Fri, Jul 6, 2012 at 1:51 PM, Alan Clark <[e-mail]> wrote:
>>> Shida
>>> 
>>> You could have all three types of discard occurring within a single stream.
>>> For example - if RTP replication is used for resilience then every interval
>>> would have the same number of duplicate/other packets as data packets and if
>>> there is a high level of jitter then there would also be late packets, early
>>> packets or both.
>>> 
>> 
>> I agree that one of early, late or others or any combination of the
>> three is a valid reporting case.
>> Perhaps there needs to be only a clarification on when to use early
>> and late or combined early and late.
>> 
>> Regards,
>> Varun
>> 
>>> Best Regards
>>> 
>>> Alan
>>> 
>>> 
>>> On 7/6/12 5:07 AM, "Shida Schubert" <[e-mail]> wrote:
>>> 
>>>> 
>>>> (as contributor)
>>>> 
>>>> So does that mean that in a single report block, early and late can co-exist
>>>> when it is described as type "both" but you can't have "other" + early,
>>>> "other" + late or "other" + both?
>>>> 
>>>> Thus, for the same reporting period, you would have separate reporting
>>>> block for the above discarded packets combination? If that is the case,
>>>> I think this should be explicitly stated in the section where the type is
>>>> described.
>>>> 
>>>> Also, the draft reads like it is dependent on Measurement Identity based
>>>> on the sub-section "number of packets discarded". If that is the case, the
>>>> Mesurement Identity should become a Normative Reference.
>>>> 
>>>> Regards
>>>> Shida
>>>> 
>>>> On Jul 3, 2012, at 11:09 AM, Qin Wu wrote:
>>>> 
>>>>> That's what I think, thank for your clarification.
>>>>> 
>>>>> Regards!
>>>>> -Qin
>>>>> ----- Original Message -----
>>>>> From: "Alan Clark" <[e-mail]>
>>>>> To: "Dan (Dan)" <[e-mail]>; "Qin Wu" <[e-mail]>; "Shida
>>>>> Schubert" <[e-mail]>; "xrblock" <[e-mail]>
>>>>> Cc: <[e-mail]>
>>>>> Sent: Monday, July 02, 2012 7:49 PM
>>>>> Subject: Re: [xrblock] WGLC for
>>>>> draft-ietf-xrblock-rtcp-xr-discardandxrblock-rtcp-xr-discard-rle-metrics
>>>>> 
>>>>> 
>>>>>> Hi Dan
>>>>>> 
>>>>>> There are some implementations of RTP that send duplicate packets (in some
>>>>>> cases every packet) in order to provide a simple form of FEC. Reporting
>>>>>> duplicate packets as "duplicates" can allow the user to determine what
>>>>>> proportion of lost packets are being concealed by the process.  For example,
>>>>>> if I send 1000 packets but duplicate these in order to provide FEC - then
>>>>>> knowing that 900 duplicate packets were discarded tells me that the network
>>>>>> packet loss rate was 10%.
>>>>>> 
>>>>>> The reason that RFC3611 excluded duplicates was that the discard count was
>>>>>> intended to show what effect late/early arriving packets were having on the
>>>>>> quality perceived by the user.  Discarded duplicates have no effect whereas
>>>>>> a discarded late packet causes a "hole" in the decoded stream that has to be
>>>>>> repaired by PLC
>>>>>> 
>>>>>> It is useful to report discards of duplicate packets "separately from" the
>>>>>> early/late arrival discard count. They should not be combined into the same
>>>>>> counter.  This means that the early/late arrival discard count would be
>>>>>> consistent with RFC3611 but there is an additional count of discarded
>>>>>> duplicate packets
>>>>>> 
>>>>>> Best Regards
>>>>>> 
>>>>>> Alan
>>>>>> 
>>>>>> 
>>>>>> On 7/2/12 6:52 AM, "Dan (Dan)" <[e-mail]> wrote:
>>>>>> 
>>>>>>> Hi Qin,
>>>>>>> 
>>>>>>> Thank you for your response.
>>>>>>> 
>>>>>>> I am fine with your proposed resolutions with the exception of item 3.
>>>>>>> The resolution proposed by you suggests including packets 'thrown away
>>>>>>> before playout (e.g., packet duplication or redundancy)' in the discard
>>>>>>> count metric. This would make the discard count metric inconsistent to
>>>>>>> the discard rate metric defined in section 4.7.1 of RFC 3611 which
>>>>>>> explicitly excludes duplicate packet discards.
>>>>>>> 
>>>>>>> Am I the only one (exaggeratedly) concerned by this inconsistency? I
>>>>>>> would love to hear other opinions.
>>>>>>> 
>>>>>>> Dan
>>>>>>> (speaking as contributor)
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>>> -----Original Message-----
>>>>>>>> From: Qin Wu [mailto:[e-mail]]
>>>>>>>> Sent: Friday, June 29, 2012 6:33 AM
>>>>>>>> To: Romascanu, Dan (Dan); Shida Schubert; xrblock
>>>>>>>> Cc: [e-mail]
>>>>>>>> Subject: Re: [xrblock] WGLC for draft-ietf-xrblock-rtcp-xr-
>>>>>>>> discardandxrblock-rtcp-xr-discard-rle-metrics
>>>>>>>> 
>>>>>>>> Hi,Dan:
>>>>>>>> Thank for your valuable review to draft-ietf-xrblock-rtcp-xr-discard.
>>>>>>>> Please see my replies inline.
>>>>>>>> 
>>>>>>>> Regards!
>>>>>>>> -Qin
>>>>>>>> ----- Original Message -----
>>>>>>>> From: "Romascanu, Dan (Dan)" <[e-mail]>
>>>>>>>> To: "Shida Schubert" <[e-mail]>; "xrblock" <[e-mail]>
>>>>>>>> Cc: <[e-mail]>;
>>>>>>> <draft-ietf-xrblock-
>>>>>>>> [e-mail]>
>>>>>>>> Sent: Thursday, June 28, 2012 8:02 PM
>>>>>>>> Subject: Re: [xrblock] WGLC for draft-ietf-xrblock-rtcp-xr-
>>>>>>>> discardandxrblock-rtcp-xr-discard-rle-metrics
>>>>>>>> 
>>>>>>>> 
>>>>>>>>> (as contributor)
>>>>>>>>> 
>>>>>>>>> I read the documents and they look almost ready for submission to
>>>>>>> the
>>>>>>>>> IESG.
>>>>>>>>> 
>>>>>>>>> Here are a few comments on draft-ietf-xrblock-rtcp-xr-discard:
>>>>>>>>> 
>>>>>>>>> 1. It would be useful I think to say more about the relation between
>>>>>>>>> this metric and the discard rate metric defined in section 4.7.1 of
>>>>>>>> RFC
>>>>>>>>> 3611. Maybe calling the metric here Discarded Packets metric would
>>>>>>>> help,
>>>>>>>>> as both RFC 3611 and this document refer to 'discard metric' but the
>>>>>>>> two
>>>>>>>>> are different (one is rate, the other packets).
>>>>>>>> 
>>>>>>>> [Qin]: Good point, I propose to change 'discard metric' in this
>>>>>>> document
>>>>>>>> into 'discard count  metric' since
>>>>>>>> abstract in this draft also uses 'discard count metric'.
>>>>>>>> 
>>>>>>>> To make this consistent with SDP parameter defined in this document, I
>>>>>>>> also like to propose to do the following change
>>>>>>>> OLD TEXT:
>>>>>>>> "
>>>>>>>> xr-format =/ xr-pd-block
>>>>>>>> 
>>>>>>>>  xr-pd-block = "pkt-dscrd"
>>>>>>>> 
>>>>>>>> "
>>>>>>>> NEW TEXT:
>>>>>>>> "
>>>>>>>> xr-format =/ xr-pdc-block
>>>>>>>> 
>>>>>>>>  xr-pdc-block = "pkt-dscrd-count"
>>>>>>>> 
>>>>>>>> 
>>>>>>>> "
>>>>>>>> 
>>>>>>>>> 2. In Section 3.1 diagram we use NBGD for Block Type, while the text
>>>>>>>> in
>>>>>>>>> Section 3.2 refers to the ND constant. We should get to a consistent
>>>>>>>>> representation
>>>>>>>> 
>>>>>>>> [Qin]: It is a typo and will fix this by changing NBGD into ND.
>>>>>>>>> 
>>>>>>>>> 3.
>>>>>>>>> 
>>>>>>>>> Section 2.1:
>>>>>>>>> 
>>>>>>>>>   A packet that arrives within
>>>>>>>>>   this time window but is too early or late to be played out
>>>>>>> shall
>>>>>>>>>   be regarded as discarded.  A packet shall be classified as one
>>>>>>> of
>>>>>>>>>   received (or OK), discarded or lost.  The Discard Metric counts
>>>>>>>>>   only discarded packets.
>>>>>>>>> 
>>>>>>>>> Section 3.1 however includes:
>>>>>>>>> 
>>>>>>>>>      00: packets are discarded due to other reasons than late
>>>>>>>>>      arrival, early arrival, or both (e.g., duplicate, redundant
>>>>>>>>>      packets).
>>>>>>>>> 
>>>>>>>>> This seems inconsistent.
>>>>>>>> 
>>>>>>>> [Qin]: Good question. To make them consistent, I propose do the
>>>>>>>> following change to Section 2.1
>>>>>>>> OLD TEXT:
>>>>>>>> "
>>>>>>>>   A packet that arrives within
>>>>>>>>    this time window but is too early or late to be played out shall
>>>>>>>>    be regarded as discarded.  A packet shall be classified as one
>>>>>>> of
>>>>>>>>    received (or OK), discarded or lost.  The Discard Metric counts
>>>>>>>>   only discarded packets.
>>>>>>>> 
>>>>>>>> "
>>>>>>>> NEW TEXT:
>>>>>>>> "
>>>>>>>> A packet that arrives within
>>>>>>>> 
>>>>>>>> this time window but is too early or late to be played out
>>>>>>>> 
>>>>>>>> or is thrown away before playout (e.g., packet duplication or
>>>>>>>> redundancy)
>>>>>>>> 
>>>>>>>> shall be regarded as discarded.  A packet shall be classified as one
>>>>>>> of
>>>>>>>> 
>>>>>>>> received (or OK), discarded or lost.  The Discard Count Metric counts
>>>>>>>> 
>>>>>>>> only discarded packets.
>>>>>>>> "
>>>>>>>> 
>>>>>>>>> 4. Is there any reasons for the Interval Metric flag (I) to be 2
>>>>>>> bits,
>>>>>>>>> rather than one bit, with the other one reserved?
>>>>>>>> 
>>>>>>>> [Qin]: Good question, I remembered we got a suggestion on the list
>>>>>>>> before from Kevin Gross which suggested to
>>>>>>>> remove Sampled metric related description from the definition of
>>>>>>>> Interval Metric flag. Since Sampled metric is
>>>>>>>> measured only at a particular time instant however metrics defined in
>>>>>>>> this document is
>>>>>>>> measured over one or several reporting intervals.To get in line with
>>>>>>> the
>>>>>>>> defintion
>>>>>>>> of the Interval Metric flag in other XR BLOCK drafts and address your
>>>>>>>> comment,
>>>>>>>> I propose the following change to the defintion of the interval metric
>>>>>>>> flag:
>>>>>>>> 
>>>>>>>> OLD TEXT:
>>>>>>>> "
>>>>>>>> Interval Metric flag (I): 2 bits
>>>>>>>> 
>>>>>>>>    This field is used to indicate whether the Discard metric is an
>>>>>>>>    Interval or Cumulative metric, that is, whether the reported
>>>>>>>>    values applies to the most recent measurement interval duration
>>>>>>>>    between successive metrics reports (I=10) (the Interval
>>>>>>> Duration)
>>>>>>>>    or to the accumulation period characteristic of cumulative
>>>>>>>>    measurements (I=11) (the Cumulative Duration).
>>>>>>>> 
>>>>>>>> "
>>>>>>>> NEW TEXT:
>>>>>>>> "
>>>>>>>> Interval Metric flag (I): 2 bits
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>>    This field is used to indicate whether the Discard Count Metric
>>>>>>> is
>>>>>>>> an
>>>>>>>> 
>>>>>>>>    Interval or Cumulative metric, Sample metric,that is, whether
>>>>>>> the
>>>>>>>> reported
>>>>>>>> 
>>>>>>>>    values applies to the most recent measurement interval duration
>>>>>>>> 
>>>>>>>>    between successive metrics reports (I=10) (the Interval
>>>>>>> Duration)
>>>>>>>> 
>>>>>>>>    or to the accumulation period characteristic of cumulative
>>>>>>>> 
>>>>>>>>    measurements (I=11) (the Cumulative Duration) or is a
>>>>>>>> 
>>>>>>>>    sampled instantaneous value (I=01) (Sampled Value). In this
>>>>>>>> document,
>>>>>>>> 
>>>>>>>>    Discard Count Metric is not measured at a particular time
>>>>>>> instant
>>>>>>>> but over
>>>>>>>> 
>>>>>>>>    one or several reporting intervals. Therefore Discard Count
>>>>>>> Metric
>>>>>>>> MUST not
>>>>>>>> 
>>>>>>>>    be chosen as Sampled Metric.
>>>>>>>> 
>>>>>>>> "
>>>>>>>> 
>>>>>>>> 
>>>>>>>>> 5. number of packets discarded:
>>>>>>>>> 
>>>>>>>>>> If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE
>>>>>>>>>   SHOULD be reported to indicate an over-range measurement.
>>>>>>>> 
>>>>>>>>> Why is this a SHOULD and not a MUST? Are there any exceptions?
>>>>>>>> 
>>>>>>>> [Qin]: No,  I will use MUST based on your comment.
>>>>>>>> 
>>>>>>>>> 6. In the IANA Considerations section:
>>>>>>>>> 
>>>>>>>>> s/ The contact information for the registrations is/ The following
>>>>>>>>> contact information is provided for all registrations in this
>>>>>>>> document/
>>>>>>>> 
>>>>>>>> [Qin]: Okay.
>>>>>>>> 
>>>>>>>>> 
>>>>>>> _______________________________________________
>>>>>>> xrblock mailing list
>>>>>>> [e-mail]
>>>>>>> https://www.ietf.org/mailman/listinfo/xrblock
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> _______________________________________________
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>>>> 
>>> 
>>> 
>>> 
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>> 
>> 
>> 
>> -- 
>> http://www.netlab.tkk.fi/~varun/