[149466] in North American Network Operators' Group
Re: Optimal IPv6 router
daemon@ATHENA.MIT.EDU (Masataka Ohta)
Sun Feb 5 21:53:41 2012
Date: Mon, 06 Feb 2012 11:52:30 +0900
From: Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp>
To: nanog@nanog.org
In-Reply-To: <CAPLq3UPr7C9sfdCmqgnALRFuviwujh+F3hir_X1yg8aWasO3tA@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Glen Kent wrote:
> With IPv6 growing, if we were to design a native IPv6 router, with
> IPv4 functionality thrown in, then is it possible to design a more
> optimal IPv6 router, than what exists today?
It depends on what you want routers to do.
As I am working on Tbps photonic routers with fiber delay lines,
the bottleneck is at constant time (nano seconds order) electric
route look up.
There, several simple 4M*16bit SRAMs is fine for IPv4 with mostly
/24 routing table entries.
IPv6 was better because TLA had was merely 13bit long with only
8192 entries.
However, as the idea of TLA was abandoned long before and a lot
more than /24 is, seemingly, necessary for route look up of IPv6
backbone, I'm afraid IPv6 needs large amount of power consuming
content addressable memories.
Without any (defacto) standard prefix length at the IPv6 backbone,
it is simply impossible to say "optimal".
Masataka Ohta
