I have many remote 2811 routers. Sometime after a power outage, they will lose BGP connection to ISP.
These are my findings.
a. the show ip inter brief showed atm 0/0/0 was up/up.
b. router is not able to ping ISP router.
The BGP router is no longer on the routing table.
c. I am able to ping ISP edge router from my workstation remotely.
d. The BGP status is in Active state.
e. I shut/no shut atm 0/0/0, BGP would get established.
f. After step 5, some routers would stay connected, but some would lose connection again; BGP would returned Active, and atm remained at up/up.
I have 2 questions.
1. Why BGP is in active state, but atm 0/0/0 showed up/up in sh ip interface bri?
2. Is this a layer 3 or a layer 4 problem on my end?