OSPF Default Route Advertising With Tracking

[guillermolzn]

Hi Forum Community,

I'm wondering if anyone can help me out:

Due to some company regulations I can't be part of a routing group, so I'm using sla tracks to failover to another route.

Initially I started using statics, but now I’m switching to OSPF over GRE IPsec tunnel.

everything works fine, but the only thing I can't get through is how can I advertise the default route when the tracking is down?:

EX:

default route:
ip route 0.0.0.0 0.0.0.0 a.b.c.d track 1

When peer goes down:

ip route 0.0.0.0 0.0.0.0 x.y.w.z 10

the above route is the one i can't get to distribute on the ospf area.
I've tried conditional default route & static redistribution on ospf.

Thanks.
Regards,
Guillermo.-

[Richard Burts]

Guillermo

I am confused. You start the post by telling us that "Due to some company regulations I can't be part of a routing group" and then go on to tell us how you are now using OSPF. Then you give us a static default route with tracking and a floating static default route. But you do not give us any details about how OSPF is set up. Can you give us a more complete and consistent explanation of what the problem is?

HTH

Rick

[guillermolzn]

Hi, Yes you're right. The information provided is not accurate enough.

My company regulations prevent my branch network equipment to be a part of the border intranet routers (primary router A and failover router B).

My core switches (A & B) are my border equipment connected to Company Primary Router A & Failover Router B

I started using OSPF on all my network routers and core switches are the ASBR's.

They are the default gateway (with different metric) and they have a static default route tracking the next hop (Company Router A)

If Router A goes down i need to update the default route for all the OSPF Area.

So this is how i solved that problem:

On the CoreSwitch A pointing to the primary router A i configured a "Track Placeholder" with a route map to a bogus ip on interface null0:

ip prefix-list PLACEHOLDER seq 5 permit 169.254.0.1/32

route-map TRACK_PLACEHOLDER permit 10

match ip address prefix-list PLACEHOLDER

On the OSPF Process i configured this route map as the default advertised route:

default-information originate always metric 10 route-map TRACK_PLACEHOLDER

And finally the statics that define when the primary A is available:

ip route 0.0.0.0 0.0.0.0 "RouterA" track 1

ip route 169.254.0.1 255.255.255.255 Null0 track 1

ip route 0.0.0.0 0.0.0.0 "CoreSwitchB" 10

With this configuration i manage to advertise the default when Primary A is available.

If it's not, the default advertised route goes out of the OSPF process.

Then on Core switch B that is connected to failover router B, I've configured the default advertised route with a higher metric and a tracking to find when Router A is up:

Router OSPF 1

default-information originate always metric 100

ip route 0.0.0.0 0.0.0.0 "CoreSwitchA" track 1

ip route 0.0.0.0 0.0.0.0 "RouterB" 10

ip route 10.11.0.2 255.255.255.255 "NextHopToRouterA"

This Way all the traffic on my OSPF Area knows where to go and where to failover without having to be a part of another routing process on the border routers.

Hope this helps.

Thanks.

Regards,

Guillermo.-