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

[Lincoln Dale]

On 16/02/2012, at 5:06 PM, Saku Ytti <saku at ytti.fi> wrote:

> 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.

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

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.


cheers, lincoln.

>