Last Call Review of draft-ietf-xrblock-rtcp-xr-loss-conceal-10

Request Review of draft-ietf-xrblock-rtcp-xr-loss-conceal
Requested rev. no specific revision (document currently at 12)
Type Last Call Review
Team Ops Directorate (opsdir)
Deadline 2014-03-28
Requested 2014-03-20
Authors Alan Clark, Glen Zorn, Claire Bi, Qin Wu
Draft last updated 2014-03-27
Completed reviews Genart Last Call review of -10 by Meral Shirazipour (diff)
Genart Telechat review of -11 by Meral Shirazipour (diff)
Secdir Last Call review of -10 by Steve Hanna (diff)
Opsdir Last Call review of -10 by Al Morton (diff)
Assignment Reviewer Al Morton 
State Completed
Review review-ietf-xrblock-rtcp-xr-loss-conceal-10-opsdir-lc-morton-2014-03-27
Reviewed rev. 10 (document currently at 12)
Review result Has Issues
Review completed: 2014-03-27


This is the OPS-DIR review of the subject draft.

I note that this draft was reviewed by Vinayak Hegde for the pm-dir;
he reviewed version 05 on May 31st, 2013.

I find no new operational issues extending RTCP-XR with this new block,
but have the following comments for clarity.


   Interval Metric flag (I): 2 bit

      This field is used to indicate whether the Loss Concealment
      metrics are Sampled, Interval or Cumulative metrics:

         I=10: Interval Duration - the reported value applies to the
         most recent measurement interval duration between successive
         metrics reports.

         I=11: Cumulative Duration - the reported value applies to the
         accumulation period characteristic of cumulative measurements.

         I=01: Sampled Value - the reported value is a sampled
         instantaneous value.

      In this document, Loss Concealment Metrics can only be measured
      over definite intervals, and cannot be sampled.  Also, the value
      I=00 is reserved for future use.  Senders MUST NOT use the values
      I=00 or I=01.  If a block is received with I=00 or I=01, the
      receiver MUST discard the block.

Since I=01 is not allowed, remove it from the list and simply
retain the explanation that follows (like I=00 was omitted).
(the text above occurs twice in the draft)


   SCS Threshold: 8 bits

      The SCS Threshold is defined as the percentage of packets
      corresponding to lost or discarded frames that must occur within a
      one second period in order for the second to be classified as a
      Severely Concealed Second.  This is expressed in numeric format
      0:8 and hence can represent a range of 0.1 to 25.5 percent loss or

      A default threshold of 5% effective frame loss (50ms effective
      frame loss ) per second is suggested.

Please provide the value of the default threshold setting.