Inspect group-to-RP mapping, PIM neighbor state and (*,G) incoming interface. This check would diagnose PIM-SM rendezvous-point mismatch, but would not first isolate the described PIM-SM RPT to SPT switchover. Begin with: Inspect (*,G) and (S,G) state, SPT flags, source RPF and join/prune counters.

Capture RA packets and inspect prefix options, A/M/O flags and client IPv6 address state. This check would diagnose IPv6 SLAAC router advertisement, but would not first isolate the described PIM-SM RPT to SPT switchover. Begin with: Inspect (*,G) and (S,G) state, SPT flags, source RPF and join/prune counters.

Compare (S,G) membership, source route, upstream PIM neighbor and RPF outcome. This check would diagnose Multicast SSM and RPF source path, but would not first isolate the described PIM-SM RPT to SPT switchover. Begin with: Inspect (*,G) and (S,G) state, SPT flags, source RPF and join/prune counters.

Enable the intended IPv6 Router Advertisements with correct prefix information and flags for the supported addressing mode. This is a legitimate response to the different issue of IPv6 SLAAC router advertisement, but it does not correct the specific PIM-DM flood and prune behavior condition reported. The relevant technical distinction is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

Correct the unicast or multicast RPF topology so the accepted packet arrives on the expected upstream interface. This is a legitimate response to the different issue of Multicast reverse-path forwarding, but it does not correct the specific PIM-DM flood and prune behavior condition reported. The relevant technical distinction is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

Enable correct IGMP snooping and validate router-port and receiver-port learning for the multicast VLAN. This is a legitimate response to the different issue of IGMP snooping multicast fanout, but it does not correct the specific PIM-DM flood and prune behavior condition reported. The relevant technical distinction is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

The intended security associations establish and permitted tunnel traffic traverses encrypted. That observation would support a separate case of IPsec peer proposal compatibility, not verification of the reported PIM-DM flood and prune behavior. The relevant observable outcome here is: Interfaces with subscribers retain multicast forwarding while pruned branches do not receive sustained data.

An authorized failover moves the alternate link to forwarding without creating a loop. That observation would support a separate case of RSTP alternate port failover, not verification of the reported PIM-DM flood and prune behavior. The relevant observable outcome here is: Interfaces with subscribers retain multicast forwarding while pruned branches do not receive sustained data.

The RP learns the new source and downstream receivers obtain traffic after registration. That observation would support a separate case of PIM first-hop source registration, not verification of the reported PIM-DM flood and prune behavior. The relevant observable outcome here is: Interfaces with subscribers retain multicast forwarding while pruned branches do not receive sustained data.

OSPF LSAs and neighbor identities use router IDs that must uniquely identify routers in the routing domain. This explains OSPF duplicate router IDs, but not why the issue in this scenario occurs. The specific mechanism is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

IGMP uses group membership messages and queries to maintain last-hop receiver state. This explains IGMP last-hop membership queries, but not why the issue in this scenario occurs. The specific mechanism is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

PIM-SM any-source multicast uses a rendezvous point to connect new sources and receivers. This explains PIM-SM rendezvous-point mismatch, but not why the issue in this scenario occurs. The specific mechanism is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

Bypassing RPF understanding can cause duplicate streams or persistent multicast blackholes. This consequence is associated more directly with Multicast reverse-path forwarding. For the stated conditions the immediate exposure is: Deploying dense mode on a sparse WAN may produce unnecessary transient multicast traffic.

Misdiagnosing normal 2-Way state can lead to disruptive election and network-type changes. This consequence is associated more directly with Broadcast OSPF DR and BDR election. For the stated conditions the immediate exposure is: Deploying dense mode on a sparse WAN may produce unnecessary transient multicast traffic.

A receiver's healthy shared tree does not deliver an unregistered source automatically. This consequence is associated more directly with PIM first-hop source registration. For the stated conditions the immediate exposure is: Deploying dense mode on a sparse WAN may produce unnecessary transient multicast traffic.

Inspect matching rule, applied attributes, selected route and resolved FIB next hop. This check would diagnose Route-policy next-hop and preference application, but would not first isolate the described PIM-DM flood and prune behavior. Begin with: Inspect PIM-DM interface state, prune timers, group distribution and receiver placement.

Inspect IGMP version, receiver reports, group address and installed source list. This check would diagnose IGMPv3 source-specific membership, but would not first isolate the described PIM-DM flood and prune behavior. Begin with: Inspect PIM-DM interface state, prune timers, group distribution and receiver placement.

Compare MST configuration digests, VLAN maps, revisions and CIST boundary state. This check would diagnose MSTP VLAN-to-instance mapping, but would not first isolate the described PIM-DM flood and prune behavior. Begin with: Inspect PIM-DM interface state, prune timers, group distribution and receiver placement.

Restore the approved first-hop PIM DR and source Register path toward the RP. This is a legitimate response to the different issue of PIM first-hop source registration, but it does not correct the specific PIM-DM flood and prune behavior condition reported. The relevant technical distinction is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

Correct the unicast or multicast RPF topology so the accepted packet arrives on the expected upstream interface. This is a legitimate response to the different issue of Multicast reverse-path forwarding, but it does not correct the specific PIM-DM flood and prune behavior condition reported. The relevant technical distinction is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

Restore consistent MST region definitions or explicitly design a safe boundary between distinct regions. This is a legitimate response to the different issue of MSTP region mismatch on trunks, but it does not correct the specific PIM-DM flood and prune behavior condition reported. The relevant technical distinction is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

An unauthorized bridge is blocked or the port enters its defined protected state without changing the core root. That observation would support a separate case of RSTP edge-port BPDU protection, not verification of the reported PIM-DM flood and prune behavior. The relevant observable outcome here is: Interfaces with subscribers retain multicast forwarding while pruned branches do not receive sustained data.

Under comparable occupancy, channel utilization and retry rates improve with adequate per-user throughput. That observation would support a separate case of High-density WLAN RF plan, not verification of the reported PIM-DM flood and prune behavior. The relevant observable outcome here is: Interfaces with subscribers retain multicast forwarding while pruned branches do not receive sustained data.

Selected high-bandwidth groups transition to the intended (S,G) shortest paths without duplicate streams. That observation would support a separate case of PIM-SM RPT to SPT switchover, not verification of the reported PIM-DM flood and prune behavior. The relevant observable outcome here is: Interfaces with subscribers retain multicast forwarding while pruned branches do not receive sustained data.

PIM-SM can initially use an RP tree and later join a source-rooted SPT for efficient delivery. This explains PIM-SM RPT to SPT switchover, but not why the issue in this scenario occurs. The specific mechanism is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

Edge-port safeguards prevent unintended bridge participation where endpoint-only connections are expected. This explains RSTP edge-port BPDU protection, but not why the issue in this scenario occurs. The specific mechanism is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

OSPF protocol authentication rejects Hellos or updates that do not meet the agreed security parameters. This explains OSPF authentication-key mismatch, but not why the issue in this scenario occurs. The specific mechanism is: PIM Dense Mode initially floods multicast and prunes branches without downstream receivers.

A receiver's healthy shared tree does not deliver an unregistered source automatically. This consequence is associated more directly with PIM first-hop source registration. For the stated conditions the immediate exposure is: Deploying dense mode on a sparse WAN may produce unnecessary transient multicast traffic.

Shared credentials or bypassed NAC can grant former employees access to protected wireless networks. This consequence is associated more directly with WLAN 802.1X authentication and NAC. For the stated conditions the immediate exposure is: Deploying dense mode on a sparse WAN may produce unnecessary transient multicast traffic.

Keeping all high-rate flows on a poor shared-tree path can waste core bandwidth. This consequence is associated more directly with PIM-SM RPT to SPT switchover. For the stated conditions the immediate exposure is: Deploying dense mode on a sparse WAN may produce unnecessary transient multicast traffic.

Inspect multicast route incoming interface, unicast route toward source, and RPF fail counters. This check would diagnose Multicast reverse-path forwarding, but would not first isolate the described PIM-DM flood and prune behavior. Begin with: Inspect PIM-DM interface state, prune timers, group distribution and receiver placement.

Inspect route-policy node IDs, if-match criteria, apply clauses and hit counts. This check would diagnose Route-policy permit and deny node order, but would not first isolate the described PIM-DM flood and prune behavior. Begin with: Inspect PIM-DM interface state, prune timers, group distribution and receiver placement.

Inspect IGMP version, receiver reports, group address and installed source list. This check would diagnose IGMPv3 source-specific membership, but would not first isolate the described PIM-DM flood and prune behavior. Begin with: Inspect PIM-DM interface state, prune timers, group distribution and receiver placement.