Extreme BlackDiamond

Mon Oct 13 07:50:20 UTC 2003

>> This is the kicker and real question: does it require the CPU to forward
>> regular traffic? I believe the answer is yes, the Extreme is a flow-based
>> architecture and the first packet of each unique flow (however it is
>> defined) will need to be processed by the CPU. This is why the problems
>
> Yes, exactly what I'm saying. Flow here is defined as a destination IP
> number.
>
No... Flow is defined as at least the unique combination of source and
destination addresses, and, often, the unique combination of source and
destination IP addresses and port numbers + the layer 4 protocol used.

> I can understand how a virus like Welchia can affect a flow-based
> architecture like Extremes. I was under the impression that CEF enabled
> Cisco gear wouldnt have this problem, but Cisco has instructions on their
> webpage on how deal with it and cites CPU usage as the reason. With CEF I
> thought the CPU wasn't involved? CEF is perhaps differently implemented
> on  different plattforms?
>
CEF is a flow-based solution much like Extreme's.  There are enhancements
to CEF in some of Cisco's newer products (such as dCEF) which take some of
this off of the CPU.

Owen