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

[Varun Singh <[e-mail]>]

Hi Dan,

Comments inline.

On Thu, Jun 28, 2012 at 3:02 PM, Romascanu, Dan (Dan)
<[e-mail]> wrote:
> (as contributor)
>
> I read the documents and they look almost ready for submission to the
> IESG.
>
[snip--discard draft, only keeping discard rle]

> Here are a few comments on
> draft-ietf-xrblock-rtcp-xr-discard-rle-metrics:
>
> 1. Runing idnits indicates that references to RFC 3551 and RFC 5760 are
> unused.

These have been removed. Also Discard and Burst Gap Discard are
changed to Informative References.

>
> 2. Section 3 - explain that the BT field MUST be assigned the DRLE value
> assigned by IANA as per the assignment required in the IANA
> Considerations section. Also there are three 'rsvd' bits in Figure 1,
> while the text mentions only 2.
>

The text should say 3 and the updated draft will correct that.

NEW TEXT:
     Block Type (BT, 8 bits) A Run-length encoded Discarded Packets Report
     Block is identified by the constant DRLE.
     [Note to RFC Editor: please replace DRLE with the IANA provided RTCP XR
     block type for this block.]

> 3. Section 4 - explain that the BT field MUST be assigned the BDR value
> assigned by IANA as per the assignment required in the IANA
> Considerations section.
>
NEW TEXT:
     Block Type (BT, 8 bits) A Run-length encoded Discarded Packets Report
     Block is identified by the constant BDR.
     [Note to RFC Editor: please replace BDR with the IANA provided RTCP XR
     block type for this block.]


> 4. Is there any reasons for the Interval Metric flag (I) to be 2 bits,
> rather than one bit, with the other one reserved?

There is a question for consistency across documents. AFAIK the only place the
sampled metric is used is the PDV (Packet Delay Variation
http://tools.ietf.org/html/draft-ietf-xrblock-rtcp-xr-pdv-03) draft, but the
measurement-identity draft does not carry the sampled duration.
Moreover, we do not use the sampled metric so we could just use 1 bit
for the Interval metric.

If we use 1-bit I flag then, all other documents that do not use the
Sampled Metric
should also use 1-bit I flag, else we should use the 2-bit I flag and
mention that the
Sampled metric cannot be used.


An off-topic question: if the sampled value duration is not carried in the
measurement identity block, does it need to be specified somewhere
in the RFC or some reference?


Regard,
Varun




-- 
http://www.netlab.tkk.fi/~varun/