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Re: draft-van-beijnum-multi-mtu-05.txt

Michael Richardson <mcr+ietf@sandelman.ca> Wed, 06 April 2016 17:12 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: David Lamparter <equinox@diac24.net>
Subject: Re: draft-van-beijnum-multi-mtu-05.txt
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Date: Wed, 06 Apr 2016 13:12:45 -0400
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Cc: Iljitsch van Beijnum <iljitsch@muada.com>, 6man <ipv6@ietf.org>
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David Lamparter <equinox@diac24.net> wrote:
    > Now the hard bit; L2 devices messing with L2 addresses.  The device
    > class I have in mind here are 802.11 "client to wired" bridges.  They
    > connect to wifi as plain clients and have one or more LAN ports
    > supporting multiple devices.  802.11 restricts them to the single MAC
    > address their radio has, so what they do is they "MAC-NAT" everything
    > behind them.  (They rewrite ARP & ND and have an address table to undo
    > it on incoming wireless packets.)

This definitely falls into the category of stupid-layer-2 tricks to get
around a lack of a routed (homenet-style) layer-3.  sigh.  IPv4 legacy.

It seems you are saying with can deal with this problem with:

> I believe the better choice here is "Neighbors are identified by their IPv6
> link-local address".  This removes any possibility for 2 hosts to be
> conflated into a single neighbor even in the presence of 'broken' L2
> devices.



--
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-

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