[135423] in North American Network Operators' Group
Re: Using IPv6 with prefixes shorter than a /64 on a LAN
daemon@ATHENA.MIT.EDU (Mark Smith)
Tue Jan 25 04:30:51 2011
Date: Tue, 25 Jan 2011 19:59:34 +1030
From: Mark Smith <nanog@85d5b20a518b8f6864949bd940457dc124746ddc.nosense.org>
To: sthaug@nethelp.no
In-Reply-To: <20110125.070230.74664425.sthaug@nethelp.no>
Cc: carlos@lacnic.net, nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Tue, 25 Jan 2011 07:02:30 +0100 (CET)
sthaug@nethelp.no wrote:
> > > IPv6 is classless; routers cannot blindly make that assumption for "performance optimization".
> > >
> > Blindly, no. However, it's not impractical to implement fast path switching that
> > handles things on /64s and push anything that requires something else
> > to the slow path.
>
> Any vendor who was stupid enough to do *hardware* switching for up to
> /64 and punted the rest to software would certainly not get any sales
> from us.
>
Actually, they'd most likely punt the rest to exact match rather than
longest match cams. Exact match cams are cheaper because they're
simpler, and have been made even more so because they've been for more
than a decade layer 2 switches, and they're are far many more of them
than there are routers.
> 128 bits. No magic.
>
"magic" is another way of describing progress. Electric start cars
would have been "magic" to owners of Motorwagens.
