RE: Evaluation: draft-ietf-avt-rtcp-report-extns - RTP Control Protocol Extended Reports (RTCP XR)

["Peterson, Jon" <jon.peterson@neustar.biz>]

>                       Yes  No-Objection  Discuss  Abstain
> Jon Peterson         [   ]     [ x ]     [   ]     [   ]
>

One semi-serious note:

I think the VoIP Metrics RB is kind of bloated. The text in 4.7 says:

   Implementations MUST provide values for all the fields defined here.
   For certain metrics, if the value is undefined or unknown, then the
   specified default or unknown field value MUST be provided.

However, I think the information that is aggregated in the VoIP Metric RB
itself contains several groups of unrelated elements. For example, one group
of elements concerns delay characteristics, whereas another group concerns
measures of audio quality (signal/noise levels). It seems likely that many
applications might know how to measure delay characteristics, for example,
but not audio quality, but given that fact that all of the elements MUST be
provided in each RB, applications are required to send a lot of default
filler in the report. The document description of the RB breaks these 21
different elements into seven separate categories. I think it might have
been preferable to provide different RBs for these different categories of
elements. Obviously, if these were grouped into separate metrics RBs, you
would incur additional RB header costs if you wanted to provide multiple
metrics, so breaking this into 7 distinct RBs probably wouldn't be
appropriate - but perhaps there's a happy medium.

There are also some editorial problems with section ordering - I note for
example that throughout the text the IANA Considerations are referred to as
Section 5, when they are in fact in Section 6.

- J