Question 510
An IGMP service uses the wrong version on an access-router interface. Observed: IGMPv3 receivers cannot express source include lists to the router. Which acceptance observation best confirms that the proposed change worked?
Explanation
Correct Answer
This acceptance criterion tests the actual fault. The source evidence was IGMPv3 receivers cannot express source include lists to the router. The correction addresses local igmp version is fixed at an earlier membership model; success requires the interface records expected source-specific membership state.
Incorrect Answers
This result is useful in another case with evidence One RP fails but receivers stay joined to a dead shared tree. It does not test recovery from igmpv3 receivers cannot express source include lists to the router. Check instead whether the interface records expected source-specific membership state.
It confirms an unrelated service correction: RP address unicast reachability is unstable through recursive routes. The present case reports IGMPv3 receivers cannot express source include lists to the router. Its completion test is The interface records expected source-specific membership state.
That observation would verify a separate fault involving spt threshold or pim source-tree behavior is not aligned to the service policy. Its symptom is Shared-tree traffic continues after the receiver requests shortest-path switchover. For this case the actual issue is local igmp version is fixed at an earlier membership model, and the relevant success signal is The interface records expected source-specific membership state.