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

[Saku Ytti]

On (2012-02-16 17:44 +1100), Skeeve Stevens wrote:

> Just a question with the 4500-X.  Why would the routing performance be
> halved for v4 vs v6?
> 
> IPv4 Routing Performance: 245Mpps
> IPv6 Routing Performance: 122Mpps

I'd like to understand how could you technically make IPv4 and IPv6 lookup
numbers same. Short of artificially slowing down or reporting IPv4 rates
conservatively.

What type of mtrie stride could possibly do this? IPv4 8-8-8-8 and IPV6
16-16-16-16-16-16-16-16, this would make IPv6 mtrie depth and width 2x of
IPV4.
For them to be same depth IPv6 stride would need to be
4294967296-4294967296-4294967296-4294967296 if you could have that wide
stride, IPv4 could be looked up from flat mtrie.

It's very difficult for me to understand how to do these in same constant
time, without having very poor IPV4 implementation.

-- 
  ++ytti