Static Routing 6500 MFSC

[jason.hines]

Senario: Two Static routes too the same destination via two different next hop address! Will traffic be routed round robin using alternate next hops or, will only one get used at a time.

[h.dziewa]

There will be two routes installed in the routing table. The actual traffic sharing will depend on the IOS switching method in effect (process, fast, CEF,) either per-packet, per-destination or per flow.

[jason.hines]

Thanks for your help so far. We have deployed CEF

as our switching method and i am interested to know how traffic would be shared over the two routes. Are you able to explain further.

Regards

Jason Hines

[h.dziewa]

By default the traffic will be load shared per destination in any switching method. You can enable per packet load sharing under each interface when using process switching or cef. Once you have cef enabled on the interface, the sharing will be a derivation of destination sharing, what's normally called per flow load sharing. That's what you should have. I'm not a fan of per packet sharing as there are issues with that, especially with packets arriving out of order.

[ruwhite]

By default, load sharing is:

-- per packet with process switching.

-- per source/destination pair with CEF.

You can turn on per packet with CEF, but you can't do per destination with process--it's not possible, because of the way the ip input process (which does the actual switching in the process path) and the routing table interact. Fast is per destination only, but we don't care about fast any longer, since unicast fast is gone/dead.

Hope that helps....

:-)

Russ.W