Question 530
An access PE sees repeated PIM neighbor resets on a multicast interface. Observed: PIM Hellos traverse a link whose multicast control traffic is filtered. After the correction, which result would most convincingly show that this fault is resolved?
Explanation
Correct Answer
After permit authorized PIM neighbor control traffic without opening unrelated multicast flood, inspect whether pIM neighbors remain Up and multicast joins propagate. This closes the loop between the reported observation (PIM Hellos traverse a link whose multicast control traffic is filtered) and the underlying issue (A control-plane filter blocks required PIM packets on the transit segment).
Incorrect Answers
That observation would verify a separate fault involving legacy any-source join configuration remains after the ssm group move. Its symptom is Receiver packets still target a shared-tree RP that no longer has active mapping. For this case the actual issue is a control-plane filter blocks required pim packets on the transit segment, and the relevant success signal is PIM neighbors remain Up and multicast joins propagate.
This result is useful in another case with evidence The provider MVPN receives control routes but does not deliver customer stream data. It does not test recovery from pim hellos traverse a link whose multicast control traffic is filtered. Check instead whether pIM neighbors remain Up and multicast joins propagate.
It confirms an unrelated service correction: The rendezvous point address is missing or unreachable for the ASM group. The present case reports PIM Hellos traverse a link whose multicast control traffic is filtered. Its completion test is PIM neighbors remain Up and multicast joins propagate.