Hello, I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. This draft defines a new message to tell TRILL implementations to flush certain reachability information it has learned. It seems quite extensible and complete. The security considerations are adequate and discuss what would happen if these messages are not secured. The draft is "Ready" for publication. One editorial nit (to show I really did read it!): in section 2.2, "...where using a set of contiguous blocks if cumbersome." should be "is cumbersome" I think. regards, Dan.