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. Al 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 discard. 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. -=-=-=-=-=-=-=-