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Re: [RRG] Idea for shooting down
On Nov 28, 2007, at 6:18 AM, Tom Petch wrote:
I wonder about router capacity, that is that the Internet only
works because
routers are incredibly fast at 'parsing' IPv4 addresses and I think
that that is
the inherent nature of an IP address, rather than because ASICs
have been
optimised for that task. So what I wonder about is the speed of
routers at the
transition from s+x flat routing to the next level down, s+x-1; an
alternative
could be to put the equivalent of the AFI bits into the middle of
an IPv6
address (howls of protest) with an IPv4 address in the lower order
bits, so
preserving the single bit-structure to parse.
I can vouch that routers are incredibly fast at doing longest-match
lookups because folks have put in incredible amounts of work into the
ASICs. Yes, of course, it could be much, much worse, but doing
longest-match can in no way be construed as 'simple' to implement in
hardware.
That said, if we want to make forwarding plane changes (and all of
the proposals that I've seen involve some changes somewhere ;-),
making those changes in the ASICs is not unreasonable.
Tony
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