[Gen-art] Gen-ART Last Call review of draft-ietf-dnsop-edns-tcp-keepalive-04

Brian E Carpenter <brian.e.carpenter@gmail.com> Mon, 23 November 2015 01:58 UTC

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From: Brian E Carpenter <brian.e.carpenter@gmail.com>
To: draft-ietf-dnsop-edns-tcp-keepalive.all@ietf.org, General Area Review Team <gen-art@ietf.org>
Organization: University of Auckland
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Date: Mon, 23 Nov 2015 14:58:08 +1300
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Subject: [Gen-art] Gen-ART Last Call review of draft-ietf-dnsop-edns-tcp-keepalive-04
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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

Document: draft-ietf-dnsop-edns-tcp-keepalive-04.txt
Reviewer: Brian Carpenter
Review Date: 2015-11-23
IETF LC End Date: 2015-11-30
IESG Telechat date:

Summary: Ready with issues

Comment: These are only standards-language issues, nothing fundamental.

Major Issues:

Last paragraph of section 3.2.2.  Receiving Responses:

   A DNS client that sent a query containing the edns-keepalive-option
   but receives a response that does not contain the edns-keepalive-
   option should assume the server does not support keepalive and behave
   following the guidance in [DRAFT-5966bis].  This holds true even if a
   previous edns-keepalive-option exchange occurred on the existing TCP

Firstly, shouldn't that "should" be a SHOULD?

More important, [DRAFT-5966bis] really looks like a normative reference to me.
I couldn't code this without reading that reference. It's already entering
Last Call so hopefully this won't waste much time.

Section 3.6.  Anycast Considerations:

   Changes in network topology between clients and anycast servers may
   cause disruption to TCP sessions making use of edns-tcp-keepalive
   more often than with TCP sessions that omit it, since the TCP
   sessions are expected to be longer-lived.  Anycast servers MAY make
   use of TCP multipath [RFC6824] to anchor the server side of the TCP
   connection to an unambiguously-unicast address in order to avoid
   disruption due to topology changes.

IMHO, [RFC6824] is another normative reference; and it's a downref since
it's an Experimental RFC. I think you could avoid this by weakening
the last sentence a bit:

   It might be possible for anycast servers to avoid disruption due to
   topology changes by making use of TCP multipath [RFC6824] to anchor
   the server side of the TCP connection to an unambiguously unicast address.