BGP failover not working as expected

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BGP failover not working as expected

L1 Bithead



Our PA 220 is running 2 eBGP's  with 2 CE (WAN) routers.

Those 2 CE routers will run eBGP with respective ISP's. 


We control the routing through Local preference. 


Routes learned via primary CE 1 has LP of 500

Routes learned via secondary CE 2 has LP of 250


What happened was BGP went down between CE 1 and ISP.

BGP didn't go down between CE 1 and our PA 220.

As a result PA 220 was still sending traffic to CE1 

Ideally the routes coming in from CE1 should have disappeared and routes coming from CE2 in local RIB table with LP 250 should have been preferred but that didn't work.


When I exported the logs at the duration of outage when BGP was down for almost 35 mins, traffic was always taking CE1 path.


Anyone experienced this and can share some insights to fix this, thanks 


L4 Transporter

Why do you need to include the PAs in BGP? If the routers are handling BGP, just point a default on the PAs toward a VRRP address on the routers and let them handle BGP.

When the ISP was down on CE1, what did it's routing table have in it?  You'll probably need to do a controlled outage to work through why it wasn't working.

We don't use static routing in our network so this solution does not suits us. thanks

To get any more info, you'll likely need to bring down one of the ISPs to see what the routing tables look like on each router and why traffic still goes through CE1.

Do you have ibgp between the CE routers? 

What routes do you take from each ISP? 

We are looking at that solution to build iBGP but even with this design failover should have worked.

As both CE 1 and 2 advertise default routes and some specific network routes to us.

We manipulate them via Local Preference as mentioned in original post. 

Do you see the expected entries in the routing table on the PA?

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