OSPF toggling on neighboring routers when BigIP is connected to them

Hello All,

 

 

I've BigIP 3400 LTM installed in HA mode (Active - Standby) at telecom carrier (See network diagram attached). OSPF module is licensed and running on BigIP.

 

 

It is running TMOS 9.4.5 HF2.

 

 

Past 10 days I've been observing that OSPF toggles frequently on Cisco neighbors i.e. there are adjacency changes frequently.

 

 

The occurrence of adjacency changes is quiet sporadic but when such an event happens subscribers start complaining about poor browsing and delayed ping responses.

 

 

I set the priority of ospf process on inside and outside vlans to '0'; Zero in order to ensure that BigIPs are never considered as a candidate during DR and BDR election. But the problem still persists.

 

 

I also disabled OSPF on standby unit. Yet it never helped.

 

 

I bypassed BigIPs and suprisingly, the OSPF toggles on Cisco routers/L3 switches stopped and it runs absolutely well.

 

 

The moment I get BigIP inline between Cisco gears, the OSPF toggling starts.

 

 

I would appreciate, your thoughts on this issue.

 

 

Sagar.

 

sagar.brit@gmail.com