Subject: I-D Action: draft-ietf-6man-maxra-02.txt

From: [email-masked]
Date: Thu, 09 Mar 2017 20:12:06 -0800

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the IPv6 Maintenance of the IETF.

        Title           : Support for adjustable maximum router lifetimes per-link
        Authors         : Suresh Krishnan
                          Jouni Korhonen
                          Samita Chakrabarti
                          Erik Nordmark
                          Andrew Yourtchenko
	Filename        : draft-ietf-6man-maxra-02.txt
	Pages           : 6
	Date            : 2017-03-09

Abstract:
   The neighbor discovery protocol specifies the maximum time allowed
   between sending unsolicited multicast Router Advertisements from a
   router interface as well as the maximum router lifetime.  It also
   allows the limits to be overridden by link-layer specific documents.
   This document allows for overriding these values on a per-link basis.

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-6man-maxra/

There's also a htmlized version available at:
https://tools.ietf.org/html/draft-ietf-6man-maxra-02

A diff from the previous version is available at:
https://www.ietf.org/rfcdiff?url2=draft-ietf-6man-maxra-02

Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org.

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

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From: Lorenzo Colitti <[email-masked]>
Date: Fri, 10 Mar 2017 13:46:41 +0900

>    This document allows for overriding these values on a per-link basis.

The changes proposed by this draft are fine, but I have concerns about the
stated rationale.

Rationale: it makes no sense to say that we should be able to extend the
maximum RA timer above 9000 seconds because multicast is inefficient on
some links, and then cite a draft that says that multicast is not efficient
on 802.11 networks. On 802.11 networks, multicast is not as reliable as
unicast, but it's certainly not the case that one packet every 9000 seconds
is a problem. Maybe instead of citing 802.11, remove all mention of 802.11
and focus only on the 3GPP use case? Or, in addition to that, say that for
some power-constrained nodes, one packet every 9000 seconds might still be
too much.

Also: since we continue to see implementers do bad things such as set
maxinterval to 4s and router lifetime 12s on a wifi network, I would add to
the end of section 4:

As explained in Section 3, the relationship between MaxRtrAdvInterval and
AdvDefaultLifetime must be chosen to take into account the probability of
packet loss.