The AR1200 running V200R007C00SPCb00 fails to establish a BGP peer relationship with a carrier's device.
1. Ping the AR1200 and the carrier's device from each other. The ping succeeds.
2. Check whether an ACL is configured for BGP packets. No ACL is configured.
3. Check diagnostic logs and find that a large number of the following logs: The router received NOTIFICATION message from peer 172.24.80.190. (ErrorCode=2, SubErrorCode=2, BgpAddressFamily=Public, ErrorData=6afe0000)
4. Check the meanings of the fields in the logs. The value 2 of ErrorCode indicates the Open packet, and the value 2 of SubErrorCode indicates the peer AS error.
5. Change the AS number on the carrier's device and check whether the fault persists. The fault is rectified.
The AS number is configured incorrectly on the carrier's device.
Change the AS number on the carrier's device.
Locate the fault according to the troubleshooting insights. Obtain diagnostic logs or configurations from the customer to facilitate troubleshooting. You can also locate the cause based on the meanings of BGP error codes.