nanog mailing list archives

Re: filtering /48 is going to be necessary


From: Masataka Ohta <mohta () necom830 hpcl titech ac jp>
Date: Mon, 12 Mar 2012 15:17:46 +0900

William Herrin wrote:

C) Big iron is either using massively parallel FIBs (many copies of
the radix tree) or they're using TCAM instead of DRAM, a specialized
tristate version of SRAM. In either case, you're talking 10 to 100
times the cost, ten times the power consumption and ten times the heat
versus DRAM.

TCAM is a specialized version of CAM. CAM is much worse than SRAM.

A router handling 10M routes is achievable today if we're willing to
go back to $20k as the minimum cost BGP box. That's an order of
magnitude more than we have now and three orders of magnitude short of
where we need to be before we can stop sweating the prefix count.

For 16M routes, we only need /24.

With /24 aggregation, route look up is trivially easy with
a 16M entry single chip SRAM every 3ns consuming 1W.

That's why IPv4 or original IPv6 proposal with 8B address
is much better than the current IPv6.

                                                Masataka Ohta


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