Setting higher OSPF priority cost?

[KGrev]

Hi,

I think this will be an easy one for most of you but i just want to make sure.

I have a router in the field that has two links back to our main network. Both links have an ip vlan with ospf on them.

One of them is having problems and causing packet loss (Vlan425). When I shut vlan 425 to troubleshoot and it uses vlan 325, the traffic clears up. I'd like to set a cost to vlan 425 so it can use vlan 325 but still have redundancy while i look into the issue on 425.

Both int vlans have "ip ospf priority 0" on them. Would I change the priority number or add a cost to it?

Than you for your time.

[Harold Ritter · Accepted solution]

Hi @KGrev ,

You need to set the cost higher on Vlan425, so traffic will prefer Vlan325. Make sure you do it on both sides for traffic to prefer Vlan325 in both directions.

Regards,

[KGrev]

Harold,

Thanks for your help.

Do you suggest that I leave the priority set as it is and add another line for cost?

Thank you

[paul driver]

Hello

The opsf priority interface cost isnt the same as the ospf interface cost

int x/x

"ip ospf priority xx"  =  is applicable to broadcast/non broadcast ospf interrface types pertaning to ospf DR/BDR election = higher value most preffered
"ip ospf cost xx" = is applicable to setting interface cost for routing path manipulation, if interface cost is not manaully set it is then automatically calculated at 10^8 pertaining the default reference bandwidth of 100mb =  higher value less preffered  

[KGrev]

Mr Paul,

Thank you for your reply.

If I want vlan 425 to be used secondary to vlan 325, do you recommend I just add an ospf cost to it?

Thank you

[paul driver · Accepted solution]

Hello

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@KGrev wrote:

Mr Paul,

Thank you for your reply.

If I want vlan 425 to be used secondary to vlan 325, do you recommend I just add an ospf cost to it?

Thank you

---

Then I would suggest  to the set interface  lan 425 ospf cost to be less preffered

int vlan 425

"ip ospf cost xx" < higher value less preffered)

[KGrev]

Ok Mr Paul, that is working. Thank you.