DMVPN/OSPF and default route

[davem1]

I have a dual-hub DMVPN setup running OSPF. The issue I am having that the default route that's being injected is preferred on the secondary hub instead of the primary. I've tried adjusting the metric on the default route, changing the admin distance on the secondary hub router, all with no luck. I'm looking for any other suggestions as to why the spoke prefers the secondary hub versus the primary. I have also set the ospf cost on router 1 to be lower than router 2. It might be something simple that I'm just no seeing.

[umer zubairi]

Try below configs on both the Hubs and make ip tcp adjust-mss value to 1360

HUB(config-if)# ip nhrp holdtime 300

HUB1(config-if)#ip nhrp redirect

Let us know if this works.

Cheers!

[davem1]

No joy. The default route is still preferred over the secondary hub router.

[Julio E. Moisa]

Hi

You can try:

Primary

router ospf 700 vrf Customer

default-information originate metric 10

Secondary

router ospf 700 vrf Customer

default-information originate metric 200

It should fix the inconvenience. The spokes should prefer the path with the lowest cost. 

:-)

[davem1]

I made the change, cleared the OSPF process and still no change. I had thought the same thing and added 'default-information originate metric 10' on HUB2 while leaving HUB1 as default with similar results. I do agree that given the metrics the preferred route should be HUB1, but even if I added a higher metric to the static route itself, i.e. ip route 0.0.0.0 0.0.0.0 x.x.x.x 100, I get the same result.

[Julio E. Moisa]

Hi David,

Have you turned off the Hub 2 in order to verify if Hub 1 is really advertising the default route? or remove the default-information originate on R2 to see the behavior?

[davem1]

If I shut down the tunnel on HUB2, I lose the adjacency and the default route is learned via HUB1. Once I bring the tunnel back up on HUB2, the default route resumes on HUB2.