Question 210
An upstream eBGP link migrates to a new provider router. Observed: BGP remains Idle even though next-hop IPs respond to ping. Which acceptance observation best confirms that the proposed change worked?
Explanation
Correct Answer
This acceptance criterion tests the actual fault. The source evidence was BGP remains Idle even though next-hop IPs respond to ping. The correction addresses the remote neighbor ip or expected autonomous-system setting does not match the peering contract; success requires the intended external BGP session establishes and the agreed routes appear.
Incorrect Answers
It confirms an unrelated service correction: TCP MD5 authentication keys differ between the two BGP endpoints. The present case reports BGP remains Idle even though next-hop IPs respond to ping. Its completion test is The intended external BGP session establishes and the agreed routes appear.
This result is useful in another case with evidence The transit edge begins advertising an infrastructure loopback to an external customer. It does not test recovery from bgp remains idle even though next-hop ips respond to ping. Check instead whether the intended external BGP session establishes and the agreed routes appear.
That observation would verify a separate fault involving ipv6 address-family activation is missing for that neighbor. Its symptom is The IPv4 BGP session is Established but IPv6 route exchange never starts. For this case the actual issue is the remote neighbor ip or expected autonomous-system setting does not match the peering contract, and the relevant success signal is The intended external BGP session establishes and the agreed routes appear.