Re: [xrblock] WGLC for Packet Delay Variation Metric Reporting

Hi,

Please find below my comments and questions related to this I-D. 

1. Section 1.3: 

   Metrics
   described in this draft either reference external definitions or
   define metrics generally in accordance with the guidelines in
   [RFC6390].

Why 'generally'? 

2. Section 1.4 says nothing as it stands. Maybe it should refer RFC
5481? Or maybe refer of some of the applicability stuff described in
Section 3.3? 

3. Section 2 - should not it be called 'Notations' rather than
'Definitions'? 

4. Expand SSRC at first occurrence

5. Reference [MEASI] does not exist

6.  Section 3.2 -  definition of Packet Delay Variation Metric Type
(pdvtyp) is not well in synch with the IANA considerations in Section
5.4. It does not say that the value of the field is to be interpreted as
Integer, and mentioning of bits 014-017 further enhances the confusion.
It does not mention this is an initial allocation for an IANA registry.
The three values allocated are 0,1,2 in 3.2 and 1,2,3 in 5.4 (0,1,2 is
better IMO as 0 has no special meaning, and this field allows for a max
of 16 values)

7. Section 3.2 - why are the recommendations for unavailable values
SHOULD and not MUST? For example ' If the measurement is unavailable,
the value 0x7FFF SHOULD be reported.' for Positive PDV Threshold/Peak.
Or ' If the measurement is unavailable, the value 0xFFFF SHOULD be
reported.' for Negative PDV Threshold/Peak. Are there any cases of
exception? Which are these? 

8. Same question in Section 4 for SDP Signaling. Why ' if the metric is
not available, the system receiving the SDP SHOULD send the metric block
with the flag value indicating that the metric is unavailable.' Why a
SHOULD and not a MUST?

9. Section 6: 

' This block does not provide per-packet statistics so the risk to
   confidentiality documented in Section 7, paragraph 3 of [RFC3611]
   does not apply.'

This phrase seems to say that there is not risk to confidentiality which
is not accurate. Although the statistics are not per packet the risk for
confidentiality concerning the performance on path is the same as the
one pointed to in RFC 3611. 

Thanks and Regards,

Dan

'

> -----Original Message-----
> From: xrblock-bounces@ietf.org [mailto:xrblock-bounces@ietf.org] On
> Behalf Of Shida Schubert
> Sent: Wednesday, May 02, 2012 8:02 AM
> To: xrblock
> Subject: [xrblock] WGLC for Packet Delay Variation Metric Reporting
> 
> This is an announcement of a 2 weeks XRBLOCK WG last call on
> "Report Block for Packet Delay Variation Metric Reporting" prior
> to requesting publication of the document as a proposed standard.
> 
> Please send your comments, including nits, to the list by the
> 
>   17th of May
> 
> If you read the draft and you see no issues, concerns, or nits, please
> express the fact that you have no issue progressing the draft on the
> list as well.
> 
> The latest version can be found here:
> http://tools.ietf.org/html/draft-ietf-xrblock-rtcp-xr-pdv-02
> 
> Regards
> 
>  Shida as co-chair
> 
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