ip ospf cost

Unanswered Question
Sep 27th, 2007

Suppose Router A fast ethernet0/0 is connected to Router B fast ethernet 0/0

If router A has below configuration


int fast ethernet 0/0

ip ospf cost 20

does command "ip ospf cost" is for outgoing purpose? which mean

Cost from routerA to RouterB fast ethernet 0/1 is 21

but cost from RouterB 0/1 to RouterA is default cost 2

I have this problem too.
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paul.matthews Thu, 09/27/2007 - 23:25

Incoming and outgoing can be a little confusing with routing costs.

In this case you have told router A that the cost to get to fas 0/0 is 20.

That will be used in routing calculations to get to that LAN via router A

Joseph W. Doherty Fri, 09/28/2007 - 19:30

Yes, OSPF just looks at the "outgoing" cost. Normally, you would expect a link of symmetric bandwidth to be costed the same in both directions but you can use this capability to prefer one outgoing path over another when they are actually equal or make two outgoing paths look the same when they are not.

Also, it is possible to have asymmetric bandwidth links. ADSL would be an example.


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