OSPF on active - standby BigIPs

Hi Sagar,

 

I have been looking at the diagram and configuration You have provided and I have one question: Why do you need to run OSPF there?

 

 

From my point of view it should work pretty well with statics (assuming You are not exporting a lot of routes), however if You need to access VIPs, which probably will be anywhere except servers VLAN, it is still directly connected either for Internet and/or Subscriber side. Management addresses of servers behind LTM can be either NATed or statically routed as subnet on Ciscos.

 

 

Regarding OSPF, I would suspect loosing adjacency or some other mishap in configurations of F5 and Cisco (something like graceful vs. signaled restarts, router priorities etc.). I would check Cisco configuration against ZebOS one and run a tcpdump of OSPF protocol to check what happens during traffic cut:

 

- do you have active routes to F5 when cut starts? If yes, where they point to? => If they are ok, the problem is probably not with routing.

 

- what is the state of neighboring routers? Check if they are not stuck in EXSTART, 2WAY or something similar. Check that on every node You have.

 

- who is DR/BDR? Try to force Cisco as DR and BDR by setting priority.

 

- check dumps if there are some malformed LSAs or something like that.

 

 

If You find nothing, I would recommend to open the case either with F5 and/or Cisco.

 

 

Update: do not forget to dump until traffic restores - it may be very interesting what causes that things return to normal...