Subject: [Gen-art] Gen-ART Last Call review of draft-ietf-v6ops-pmtud-ecmp-problem-04

From: Paul Kyzivat <[email-masked]>
Date: Mon, 28 Sep 2015 13:03:53 -0400

I am the assigned Gen-ART reviewer for this draft. The General Area 
Review Team (Gen-ART) reviews all IETF documents being processed by the 
IESG for the IETF Chair. Please treat these comments just like any other 
last call comments. For more information, please see the FAQ at 
<http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>.

Summary: This draft is on the right track but has open issues, described 
in the review.

Major Issues: NONE

Minor Issues:

It would be helpful if this draft described its intended target 
audience. It would also benefit from having additional references 
providing background context for the substance of the draft.

In particular, "ECMP" and "PMTUD" are used extensively, in the text and 
even the title of the draft. While these acronyms are expanded in the 
text, there are no references to definitions of them.

I sought out references for ECMP. The ones I found are RFC2991 and 
RFC2992, which are old. Is there a more recent analysis that ought to be 
considered? It seems that the problem at hand comes when using ECMP for 
load balancing across multiple servers. Is there some reference that 
talks about that? (RFCs 2991 and 2992 are more general - they could 
apply in other contexts and don't mention this use.)

The single reference in the document is to RFC4821. Is it the proper 
reference for PMTUD? It seems to be closely related, but it seems to be 
more specialized.

In the Security Considerations section a possible attack is identified, 
and a mitigation described. But then a seemingly serious drawback to the 
mitigation is also described. I think this bears more discussion.

	Thanks,
	Paul