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This option proposes: In any-source PIM-SM an RP supports initial shared-tree joining and source registration, while routers may switch to source-rooted shortest-path trees according to configured behavior and traffic. It addresses the different topic PIM sparse mode RP shared tree and shortest path transition, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: SNMP managers request device state, while traps and informs carry event notifications; SNMPv3 offers user-based authentication and optional privacy protection unlike insecure shared-community assumptions. It addresses the different topic SNMP manager polling traps and authenticated operation, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: IP multicast forwarding commonly uses an RPF check toward the source or rendezvous point to prevent loops, so an otherwise reachable multicast group may fail when packets arrive on an unexpected upstream interface. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: Inspect multicast routing entries, incoming interface, unicast RPF route for the source or RP and packet counters on the observed ingress. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: Inspect PIM-DM neighbor state, source-specific multicast entries, prune interfaces and receiver interest across the branches. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: Inspect the originating ASBR, type 5 LSA, external metric type and metric, cost toward the ASBR and actual selected external next hop. It addresses the different topic OSPF external LSAs and E1 versus E2 cost, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

That option concerns IGMPv3 source-specific selection and SSM. That follows from the targeted action: Check IGMP membership and querier operation on the receiver LAN before changing PIM routing configuration upstream.

That option concerns Switch stacking clustering and split-brain risk. That follows from the targeted action: Check IGMP membership and querier operation on the receiver LAN before changing PIM routing configuration upstream.

That option concerns Multicast reverse path forwarding checks. That follows from the targeted action: Check IGMP membership and querier operation on the receiver LAN before changing PIM routing configuration upstream.

This option proposes: Assume a router must forward every packet sent to a multicast group whenever it has a unicast default route, regardless of the packet's incoming interface. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: Assume adding an arbitrary BGP community automatically blocks a route from every router on the Internet without any peer-side policy or recognized well-known meaning. It addresses the different topic BGP community tagging and route-policy control, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: Remove all rendezvous-point configuration from an ASM sparse-mode deployment and assume that every receiver automatically knows each source location. It addresses the different topic PIM sparse mode RP shared tree and shortest path transition, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: Validate physical stack links, member roles and split-brain safeguards before considering a multi-switch logical chassis redundant. It addresses the different topic Switch stacking clustering and split-brain risk, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: Inspect multicast routing entries, incoming interface, unicast RPF route for the source or RP and packet counters on the observed ingress. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.). The better discriminating check for this case is: Review VLAN IGMP query source, version, group reports, membership timers and the downstream interface in multicast routing state.

This option proposes: Diagnose RSTP forwarding state by identifying root, designated and alternate ports and the topology's point-to-point characteristics. It addresses the different topic RSTP port roles and rapid convergence, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A floor switch has active IPTV receivers, but multicast stops after its IGMP querier leaves and group records age out.).

This option proposes: Choose OSPF summarization at the correct boundary and account for reachability when advertising aggregates. It addresses the different topic OSPF summarization at ABR and ASBR, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Explain how PIM dense mode initially distributes traffic and then prunes interfaces lacking downstream receivers. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Separate any-source group subscriptions from IGMPv3 source-specific multicast membership when implementing an SSM service. It addresses the different topic IGMPv3 source-specific selection and SSM, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: In any-source PIM-SM an RP supports initial shared-tree joining and source registration, while routers may switch to source-rooted shortest-path trees according to configured behavior and traffic. It addresses the different topic PIM sparse mode RP shared tree and shortest path transition, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Huawei ACL filtering considers rule order and match criteria; permit or deny decisions depend on the traffic-filter feature and where the ACL is applied, so a symmetric assumption about directions can be wrong. It addresses the different topic ACL traffic filter placement and rule order, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: IP multicast forwarding commonly uses an RPF check toward the source or rendezvous point to prevent loops, so an otherwise reachable multicast group may fail when packets arrive on an unexpected upstream interface. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Inspect the active RIB prefix and mask, BGP network or import-route configuration, route-policy matches and outbound Adj-RIB-Out to the peer. It addresses the different topic BGP route origin network and redistribution policy, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Inspect receiver reports containing include/exclude sources, the configured SSM group range and (S,G) state on multicast routers. It addresses the different topic IGMPv3 source-specific selection and SSM, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Inspect PIM-DM neighbor state, source-specific multicast entries, prune interfaces and receiver interest across the branches. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Internal routers prefer the intended egress path while the preference stays within the correct autonomous system boundary. It addresses the different topic BGP LOCAL_PREF within one autonomous system, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.). The better discriminating check for this case is: Review VLAN IGMP query source, version, group reports, membership timers and the downstream interface in multicast routing state. The targeted correction is: Check IGMP membership and querier operation on the receiver LAN before changing PIM routing configuration upstream.

That option concerns PIM dense mode flooding and prune mechanisms. That follows from the targeted Recommended action: Check IGMP membership and querier operation on the receiver LAN before changing PIM routing configuration upstream.

That option concerns Multicast reverse path forwarding checks. That follows from the targeted Recommended action: Check IGMP membership and querier operation on the receiver LAN before changing PIM routing configuration upstream.

This option proposes: Assume PIM-DM always requires a rendezvous point and never initially floods multicast packets to uninterested downstream segments. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Create a traffic classifier matching voice packets and assume that alone guarantees priority scheduling without any traffic behavior or attached policy. It addresses the different topic Huawei MQC traffic classification and behavior binding, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Assume a router must forward every packet sent to a multicast group whenever it has a unicast default route, regardless of the packet's incoming interface. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Inspect PIM-DM neighbor state, source-specific multicast entries, prune interfaces and receiver interest across the branches. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.). The better discriminating check for this case is: Review VLAN IGMP query source, version, group reports, membership timers and the downstream interface in multicast routing state.

This option proposes: Trace IS-IS link-state synchronization through LSP sequence numbers and summary or acknowledgment PDUs when databases differ. It addresses the different topic IS-IS LSP synchronization using CSNP and PSNP, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).

This option proposes: Check IS-IS level-1-to-level-2 route leaking and the overload bit before selecting a device as a transit path. It addresses the different topic IS-IS routing leakage and overload bit, not the directly tested IGMP querier membership reports and group timeout failure in the stated incident (A new streaming client joins a group, yet an upstream router lists no downstream IGMP membership because the access VLAN blocks its reports.).