Re: [xrblock] Tags and SSRC's in XR Blocks

Hi Alan,

in draft-clark-xrblock-rtcp-xr-qoe-00:

Numerical values for interval or duration are provided in the
      Measurement Identifier block referenced by the tag field below.

Is the measurement identifier block only used for sample duration. Interval
and cumulative measurements don't require the tag field. Is the Tag set to
0 in these cases?

On Fri, Nov 18, 2011 at 12:24, Varun Singh <vsingh.ietf@gmail.com> wrote:

> Hi Alan,
>
> draft-clark-xrblock-rtcp-xr-qoe-00 has a 6-bit tag while the Measurement
> ID block defines it as a 3-bit identifier.
>
> In draft-ietf-avt-rtcp-xr-meas-identity-02#section-2: there is a 0 bit, is
> this done so that the Tag field aligns across blocks? if so then there
> should be 2 zero bits to cover for the new I field.
>
> Also in the measurement identity draft:
>
> Bits shown as '0' in the figure SHOULD be set to zero.
>
> SHOULD be MUST?
>
>
> Cheers,
>
> Varun
>
>
> On Fri, Nov 18, 2011 at 12:57, Charles Eckel (eckelcu) <eckelcu@cisco.com>wrote:
>
>> Hi Alan,
>>
>> As this issue concerns the monarch draft as well as the measurement
>> identification block draft, it was discussed on both the avtcore and
>> xrblock lists:
>>
>> http://proxy2974.my-addr.net/myaddrproxy.php/http/www.ietf.org/mail-arch
>> ive/web/avt/current/msg14582.html<http://proxy2974.my-addr.net/myaddrproxy.php/http/www.ietf.org/mail-archive/web/avt/current/msg14582.html>
>> and
>> http://proxy2974.my-addr.net/myaddrproxy.php/http/www.ietf.org/mail-arch
>> ive/web/avt/current/msg14658.html<http://proxy2974.my-addr.net/myaddrproxy.php/http/www.ietf.org/mail-archive/web/avt/current/msg14658.html>
>>
>> The decision at that time was to remove the tag and rely on the SSRC.
>> The thread speaks to point (i) you raised. It does not speak to point
>> (ii).
>> Point (ii) was raised during the xrblock working group session with
>> week, and one of the action items for the measurement identification
>> draft was to clarify the intended usage of the measurement identity
>> block in such cases.
>>
>> Cheers,
>> Charles
>>
>> > -----Original Message-----
>> > From: xrblock-bounces@ietf.org [mailto:xrblock-bounces@ietf.org] On
>> Behalf Of Alan Clark
>> > Sent: Wednesday, November 16, 2011 11:27 AM
>> > To: xrblock@ietf.org
>> > Subject: [xrblock] Tags and SSRC's in XR Blocks
>> >
>> >
>> > The original concept for the XR blocks used the idea of a Tag to
>> relate the metrics blocks to a
>> > measurement identification block.  This approach was used for a number
>> of reasons:
>> >
>> > (i) It is more efficient as the Source SSRC, which is already in the
>> measurement identification block,
>> > does not have to be repeated for every metrics block.  As some of the
>> metrics blocks are only 3-4
>> > words in size, the redundant SSRC increases the message size by
>> 25-30%.
>> >
>> > (ii) It provides more flexibility in the organization of metrics
>> blocks into RTCP packets - allowing
>> > either one RTCP packet to contain several sets of measurement data or
>> allowing one set of measurement
>> > data to be carried over several RTCP packets.
>> >
>> > I'm not sure why the Tag was removed - was there some good technical
>> reason for this?
>> >
>> > Alan
>>
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>>
>
>
>
> --
> http://www.netlab.tkk.fi/~varun/
>

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