[j-nsp] Missing entries in route table inet.3

[Jason Koh]

Hi there

I have a problem with missing entries in my inet.3 table. Here's the situation.

I have a iBGP peer between a M20 and a Cisco 7206 router. This BGP carries ipv4 and vpnv4 routes. Now, I am running 2 different IGPs for these 2 routers that doesn't talk to each other, and so the only way they can communicate with each other is via the iBGP and some static routes between each other. These static routes are basically entries defining loopback addresses so that LDP can be established between the 2 routers.

The problem arises when the link between the 2 router flaps. The iBGP for ipv4 and vpnv4 are torn down obviously. ipv4 recovers normally but vpnv4 although establishing itself, resulted in routes received in the M20 showing Next-hop Unusable. Upon investigation, it was found that inside the inet.3 table, entries for the loopback addresses pointing to the Cisco 7206, which were previously there, are gone. Looking at inet.0, the routes for the loopback addresses are there, since they are configured previously in routing-options static. 

The only way to solve this is to first deactivate the interface entry inside protocols ldp and then reactivating it. 

Anyone out there has a similar incident or experience and would like to share their ideas on this?

Thanks.

Jason Koh
Senior Network Engineer
Pacific Internet Ltd