Question 150
A core uses multiple IS-IS levels on a shared interface. Observed: One neighbor reports only a Level 2 adjacency despite the access level being required. Which acceptance observation best confirms that the proposed change worked?
Explanation
Correct Answer
This acceptance criterion tests the actual fault. The source evidence was One neighbor reports only a Level 2 adjacency despite the access level being required. The correction addresses is-is level enablement differs between interface configurations; success requires the configured level adjacencies become operational and level-specific databases are populated.
Incorrect Answers
It confirms an unrelated service correction: The remaining interface metric on the repaired circuit is artificially high. The present case reports One neighbor reports only a Level 2 adjacency despite the access level being required. Its completion test is The configured level adjacencies become operational and level-specific databases are populated.
That observation would verify a separate fault involving import and export policy lack route-origin tagging or other feedback suppression. Its symptom is The route repeatedly returns to the protocol it came from. For this case the actual issue is is-is level enablement differs between interface configurations, and the relevant success signal is The configured level adjacencies become operational and level-specific databases are populated.
This result is useful in another case with evidence Neighbors remain Down even though interface transport and timers match. It does not test recovery from one neighbor reports only a level 2 adjacency despite the access level being required. Check instead whether the configured level adjacencies become operational and level-specific databases are populated.