Last Call Review of draft-ietf-v6ops-pmtud-ecmp-problem-04
review-ietf-v6ops-pmtud-ecmp-problem-04-opsdir-lc-chown-2015-10-19-00

Hi,

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. 

The draft describes mitigations that can be applied to address the problem of failure of
PMTUD to work correctly in ECMP load balanced or anycast networks, due to the
potential failure to deliver ICMPv6 PTB messages to the correct destination in such 
scenarios.

The problem is described clearly. Mitigations described include deeper packet inspection
(subject to router capability), replicating the PTB message, or lowering the TCP MSS
to 1280.  Each solution is not without limitations. Different implementations of the 
replication approach are described and their merits discussed, and the potential for 
an attacker to maliciously send PTB messages as part of a DoS attack is considered 
in the Security Considerations section.

In my view, this text represents a good discussion of a real, though not too common,
issue that should be documented, and as such the draft is Ready for publication.

Tim