[154941] in North American Network Operators' Group
Re: using "reserved" IPv6 space
daemon@ATHENA.MIT.EDU (Matt Addison)
Tue Jul 17 07:19:27 2012
From: Matt Addison <matt.addison@lists.evilgeni.us>
In-Reply-To: <1342509300.6281.198.camel@karl>
Date: Tue, 17 Jul 2012 07:18:28 -0400
To: Karl Auer <kauer@biplane.com.au>
Cc: NANOG List <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Jul 17, 2012, at 3:15, Karl Auer <kauer@biplane.com.au> wrote:
> Reading it with a squint: The phrase "packets [...] will be delivered to
> one router on the subnet" does not specifically exclude the possibility
> that packets will be delivered to more than one router on the subnet.
> Still, I do think it would be a little unreasonable to interpret it
> thus.
After reading some more I see how using subnet-router anycast works.
The anycast address is global in scope so the end host will only learn
1 potential next hop at a time (the routers randomize a delay when
responding to ND for a subnet-router anycast), and perform NUD as
needed to determine if their current router is up or down (RFC4861).
So you can get failover with no FHRP by using subnet-router anycast.
You just won't get sub-second failover.
