Subject: [AVT] draft-clark-avt-rtcpvoip-00.txt

From: "Alan Clark" <[email-masked]>
Date: Fri, 15 Mar 2002 15:59:29 -0500

At the AVT meeting next week these are the key points I plan to cover in the
draft-clark-avt-rtcpvoip-00.txt slot.

- Why provide RTCP extensions for VoIP metrics?
- Why base on friedman-avt-rtcp-report-extns draft?
- Metrics included and why these are complementary to those already
available
- Request comments/ feedback on approach, implementation and usage issues

Regards

Alan Clark

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

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From: "Timur Friedman" <[email-masked]>
Date: Tue, 19 Mar 2002 18:55:00 -0500

One question that will come up in the Wednesday afternoon session here in Minneapolis is whether to merge this draft with the RTCP Reporting Extensions draft (draft-friedman-avt-rtcp-report-extns-02.txt) as the Reporting Extensions draft proceeds to Experimental RFC status.

The Reporting Extensions draft provides an eight-bit type field, allowing 256 different block types to be defined.  Seven specific block types are defined in the draft, allowing other block types to be defined as the need arises.  The VoIP Metric draft proposes a block type within this framework.  This block type could be incorporated into the Reporting Extensions draft, or it could remain in the VoIP Metric draft as the first block type that is defined separately within the framework of the RTCP Reporting Extensions.

Issues to consider include how generic the block types are, and how settled the block type definitions are.

- How generic?

The block types defined in the Reporting Extensions draft contain information that could be used by a wide variety of applications, including audio, video, and measurement applications.  To the extent that the VoIP metrics are specific to voice applications, this would argue for including them in a separate draft.  On the other hand, some of the metrics are fairly generic (packet loss rate, for instance).

- How settled?

The block types defined in the Reporting Extensions draft are pretty much settled, and, in my opinion, are unlikely to change much.  The VoIP metrics are, it appears, well understood (I've seen work by Cole and Rosenbluth on the subject), which would argue for incorporating them into the Reporting Extensions draft.  But the specific format for incorporating them into RTCP reporting blocks might be less so, which would argue the other way.

Timur Friedman

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]On Behalf Of Alan
> Clark
> Sent: Friday, March 15, 2002 3:59 PM
> To: [email-masked]
> Subject: [AVT] draft-clark-avt-rtcpvoip-00.txt
> 
> 
> 
>

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From: "Alan Clark" <[email-masked]>
Date: Tue, 19 Mar 2002 21:07:35 -0500

Timur

One question that will come up in the Wednesday afternoon session here in
Minneapolis is whether to merge
this draft with the RTCP Reporting Extensions draft
(draft-friedman-avt-rtcp-report-extns-02.txt) as the
Reporting Extensions draft proceeds to Experimental RFC status.

[Alan] Either approach would be fine and we can go along the route which
gets a usable draft most quickly.

>- How generic?

The block types defined in the Reporting Extensions draft contain
information that could be used by a wide variety of applications, including
audio, video, and measurement applications.  To the extent that the VoIP
metrics are specific to voice applications, this would argue for including
them in a separate draft.  On the other hand, some of the metrics are fairly
generic (packet loss rate, for instance).

[Alan] for VoIP applications it is useful to have a little more information
on packet loss, notably packet discards by the jitter buffer, burst
density/length/spacing.  VoIP is quite sensitive to loss (including discard)
distribution - the same is true for other multimedia traffic types.

Alan Clark