Hi,

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.



Overall I find the document to be of good quality and I agree that the 


security considerations section is adequate.






While PIM is certainly not my strong suit the document is understandable 


except for the following paragraph from Section 2.1:




   The Local Interface Identifier MUST be non-zero.  The reason for
   this, is that some protocols may want to only optionally refer to an
   Interface using the Interface Identifier Hello option, and use the
   value of 0 to show that it is not referred to.  Note that the value
   of 0 is not a valid ifIndex as defined in [RFC1213].



This seems to be saying that the Local Interface Identifier must not be 0, 


except when some protocol wants to use the Interface Identifier Hello to 


not refer to any actual interface.  Which leaves me confused.




Regards,
Chris