Which end configure ospf cost

[Tzy Chun Chong]

Hi All,

Quick question, i've provided with read-only access to routers which managed by 3rd party, i can't do "show run * " command from the routers. But i try to figure out the current routing(OSPF) setup. I saw the OSPF link cost is being manipulated, as below.

Rotuer_A>sh ip ospf interface br
Interface PID Area IP Address/Mask Cost State Nbrs F/C
Gi0/1/1 65040 0 10.13.49.86/30 300 P2P 1/1

Router_A>sh ip ospf interface gi0/1/1
GigabitEthernet0/1/1 is up, line protocol is up
Internet Address 10.13.49.86/30, Area 0, Attached via Network Statement
Process ID 65040, Router ID 10.13.46.8, Network Type POINT_TO_POINT, Cost: 300

-----------------------------------------------------------

Router_B>sh ip ospf int bri
Interface PID Area IP Address/Mask Cost State Nbrs F/C
Gi0/1/0 65040 0 10.13.49.85/30 300 P2P 1/1

Router_B>sh ip ospf interface gi0/1/1

GigabitEthernet0/1/0 is up, line protocol is up
Internet Address 10.13.49.85/30, Area 0, Attached via Network Statement
Process ID 65040, Router ID 10.13.46.9, Network Type POINT_TO_POINT, Cost: 300

Question: How do i know which router(A or B) is configured the "ip ospf cost 300" command? If i can't reveal the running configuration? Any command to get the picture of this?

Thanks, i will rate for helpful reply.

[Mark Malone]

Hi

Its should be set on both sides of the link, , ospf cost should be applied to both ends of the link for it to work correctly , can you see the routing table for the metrics check each subnet on each side of the link if the route shows the cost on both sides it set both sides

[Tzy Chun Chong]

Thanks Mark,

I just read more about OSPF cost and got my answer. Your answer is partially is correct, you need not to applied at both ends of the link to work correctly, you can do 1 end default cost and another end cost 300 to influence the route selection from only 1 direction.

In my case, i think it set on both ends that's why i saw cost 300 from both directions.

I still rate you. Cheers.

[Mark Malone]

Hi

you asked how do I know without checking run config if cost is configured on both sides  ...that's why I said check the routing table that will confirm in the cost value of the subnet whether its configured both ends , if its only configured 1 side the cost wil only be in the output on 1 side in the routing table

[Tzy Chun Chong]

Yes... that is correct. I meant this statement "ospf cost should be applied to both ends of the link for it to work correctly". This is not a correct statement becoz you need not applied to both ends to work "correctly", it depends on your design requirement.