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 document is an implementation report for PIM-SM to provide 
supporting documentation for progressing PIM-SM to Internet Standard.

Note: I am in no way an expert on multicast.

Nit: The document is inconsistent when it comes to spelling out 
abbreviations, eg RP is never spelled out.

The only other comment I have is that the security considerations
section says "no implications" while 2.4 argues for the removal of 
PMBR which features in the security implications section of RFC4601. 

I don't know if the removal of PMBR makes things better or worse
but the security considerations section maybe should provide a
word or two of comment on this.

	Cheers Leif