[157038] in North American Network Operators' Group
Re: IPv4 address length technical design
daemon@ATHENA.MIT.EDU (Eugen Leitl)
Thu Oct 4 02:47:57 2012
Date: Thu, 4 Oct 2012 08:47:45 +0200
From: Eugen Leitl <eugen@leitl.org>
To: nanog@nanog.org
In-Reply-To: <28390.1349305160@turing-police.cc.vt.edu>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Wed, Oct 03, 2012 at 06:59:20PM -0400, Valdis.Kletnieks@vt.edu wrote:
> Where's Noel Chiappa when you need him?
>
> > (2) The new protocol will use variable-length address for the Host
> > portion, such as used in the addresses of CLNP,
>
> This also was considered during the IPv6 design phase, and the router
> designers had a collective cow, as it makes ASIC design a whole lot more
> interesting. And back then, line speed was a lot lower than it is now...
>
> Not saying it can't be done - but you're basically going to have to do CLNP
> style handling at 400Gbits or 1Tbit. Better get those ASIC designers a *lot*
> of caffeine, they're gonna need it...
Except that these will be pure photonic networks, and apart from optical
delay lines for your packet buffer you'd better be able to make a routing
(switching) decision while few bits of the header have streamed by your
photonic router circuit.
There is no time for any table look-ups, obviously.
And optical gates are *really* expensive, so better use few of
them. And don't add too many gate delays, too.
Above describes your setting for the next protocol. There is not
a lot of leeway in design space, I'm afraid.
