[c-nsp] Cisco's new 4500-X 10G Aggregation Switches

Saku Ytti saku at ytti.fi
Thu Feb 16 04:52:40 EST 2012


On (2012-02-16 17:31 +0800), Lincoln Dale wrote:

> Stride doesn't come into it as its not likely a mtrie lookup but
> rather FIB is a TCAM.

Yeah, I guess SUP7 isn't NPU+DRAM yet :>

> Performance is therefore less because to do a 144 bit lookup rather
> than 72 bit key (IPV4) is logically a double-wide lookup.
> 
> Not all platforms have to do that but many do.

Yes. And point remains, if you'd implement it in TCAM where atom is 144b,
it would artificially halve your IPv4 rate and your IPv4 table size, with
no apparent design wins.

If there is way to make IPv4 and IPv6 same rate, without screwing up IPv4,
I'd be curious to hear what it is.
-- 
  ++ytti


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