I have reviewed this document as part of the Operational directorate's 
ongoing effort to review all IETF documents being processed by the IESG.  These 
comments were written with the intent of improving the operational aspects of the 
IETF drafts. Comments that are not addressed in last call may be included in AD reviews 
during the IESG review.  Document editors and WG chairs should treat these comments 
just like any other last call comments. 

Overall I've found this document to be READY. I do believe that some parts' readability could be improved however, particularly Section 5. This section describes some principles a potential implementation of the spec should follow but provides little or no justification for them. I believe additional text could help.

Thank you to the authors for their great work!

Carlos