[f-nsp] High load on the MLX lp's cpu - how to avoid a fallback to software routing in case of one arm routing situations

[Niels Bakker]

Hi,

* gstammw at gmx.net (Gunther Stammwitz) [Sun 10 Dec 2006, 16:34 CET]:
>I just wanted to document to the list that there is a bug (oh sorry.. 
>foundry is calling this some sort of "feature" and doesn't want to 
>change it) in the netiron mlx software 3.1 that causes the line card 
>to fall back to cpu switching instead of hardware routing in 
>one-arm-routing-situations. This means if traffic is entering and 
>leaving the router on the same physical interface - different vlans or 
>ves don't matter - parts of it will be cpu switched. Foundry is calling 
>this one arm routing.
[..]
>no ip icmp redirect

Thanks for the tip.  Cisco routers used to need "ip route-cache 
same-interface" to enable fast-switching of such packets back in the days.

I think I've seen this on an MG8 once, too.  Wish I'd known about it 
then :)

Cheers,


	-- Niels.

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