Pass Huawei H12-821 Exam in First Attempt Guaranteed!

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 IGMPv3 source-specific selection and SSM failure in the stated incident (A deployment enables SSM in the routed network while legacy IGMPv2 receiver reports cannot express the requested source filter, so source-specific joining fails.).

This option proposes: Disable spanning tree on every redundant uplink after seeing an alternate port discard frames, treating the loop-prevention state as a fault. It addresses the different topic RSTP port roles and rapid convergence, not the directly tested IGMPv3 source-specific selection and SSM failure in the stated incident (A deployment enables SSM in the routed network while legacy IGMPv2 receiver reports cannot express the requested source filter, so source-specific joining fails.).

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 IGMPv3 source-specific selection and SSM failure in the stated incident (A deployment enables SSM in the routed network while legacy IGMPv2 receiver reports cannot express the requested source filter, so source-specific joining fails.).

This option proposes: Check IGMP membership and querier operation on the receiver LAN before changing PIM routing configuration upstream. It addresses the different topic IGMP querier membership reports and group timeout, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

This option proposes: Calculate or verify the practical failure-detection threshold from BFD transmit intervals, advertised receive intervals and the detect multiplier. It addresses the different topic BFD detection multiplier and negotiated timers, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

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 PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

This option proposes: IGMPv3 can convey source-filter information, enabling Source-Specific Multicast subscriptions for a specified source and group; an SSM design avoids relying on an ASM rendezvous point for that source tree. It addresses the different topic IGMPv3 source-specific selection and SSM, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

This option proposes: Packet selection uses the most-specific matching destination route before comparing candidate protocol preferences for identical prefixes; a broad default route does not displace a more-specific valid route solely by lower preference. It addresses the different topic Longest prefix match and route preferences, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

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 PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

This option proposes: Compare RP reachability, (*,G) and (S,G) state, PIM join or register messages and RPF interfaces before changing the multicast design. It addresses the different topic PIM sparse mode RP shared tree and shortest path transition, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

This option proposes: Inspect primary/backup controller registrations, AP failover behavior, RADIUS/802.1X results, user authorization attributes and policy applied to a test client. It addresses the different topic WLAN controller redundancy and NAC integration, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

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 PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

That option concerns RSTP port roles and rapid convergence. That follows from the targeted action: Explain how PIM dense mode initially distributes traffic and then prunes interfaces lacking downstream receivers.

That option concerns PIM sparse mode RP shared tree and shortest path transition. That follows from the targeted action: Explain how PIM dense mode initially distributes traffic and then prunes interfaces lacking downstream receivers.

That option concerns Multicast reverse path forwarding checks. That follows from the targeted action: Explain how PIM dense mode initially distributes traffic and then prunes interfaces lacking downstream receivers.

This option proposes: Evaluate non-backbone OSPF connectivity through area 0 and whether a virtual link is an appropriate temporary correction in supported topologies. It addresses the different topic OSPF backbone connectivity and virtual link design, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

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 PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.). The better discriminating check for this case is: Inspect PIM-DM neighbor state, source-specific multicast entries, prune interfaces and receiver interest across the branches.

This option proposes: Check VRRP virtual IP and virtual MAC behavior while troubleshooting hosts that retain a stale default-gateway neighbor entry after failover. It addresses the different topic VRRP virtual MAC and endpoint ARP continuity, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (A lab network enables dense-mode multicast and observes short-lived traffic on branches without receivers before prune messages take effect.).

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 PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Configure DHCP relay to forward broadcast client discovery toward a reachable server and preserve the correct client-subnet context. It addresses the different topic DHCP relay across a routed user VLAN, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Trace PIM-SM receiver joins toward an RP and subsequent shortest-path behavior when investigating delayed or suboptimal multicast. It addresses the different topic PIM sparse mode RP shared tree and shortest path transition, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

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 PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: IGMPv3 can convey source-filter information, enabling Source-Specific Multicast subscriptions for a specified source and group; an SSM design avoids relying on an ASM rendezvous point for that source tree. It addresses the different topic IGMPv3 source-specific selection and SSM, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Rapid Spanning Tree Protocol reduces convergence time by exchanging proposal/agreement information on eligible links and maintaining alternate paths, while only the root and designated forwarding ports should carry traffic in a stable tree. It addresses the different topic RSTP port roles and rapid convergence, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Review manager IP, user security level, permissions, device trap destination, authentication logs and sample interface counters or link-down notifications. It addresses the different topic SNMP manager polling traps and authenticated operation, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Review VLAN IGMP query source, version, group reports, membership timers and the downstream interface in multicast routing state. It addresses the different topic IGMP querier membership reports and group timeout, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

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 PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

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 PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.). The better discriminating check for this case is: Inspect PIM-DM neighbor state, source-specific multicast entries, prune interfaces and receiver interest across the branches. The targeted correction is: Explain how PIM dense mode initially distributes traffic and then prunes interfaces lacking downstream receivers.

That option concerns PIM sparse mode RP shared tree and shortest path transition. That follows from the targeted Recommended action: Explain how PIM dense mode initially distributes traffic and then prunes interfaces lacking downstream receivers.

That option concerns Multicast reverse path forwarding checks. That follows from the targeted Recommended action: Explain how PIM dense mode initially distributes traffic and then prunes interfaces lacking downstream receivers.

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 PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Assume that configuring a multicast source anywhere in the network automatically populates IGMP membership on a VLAN where no receiver has joined. It addresses the different topic IGMP querier membership reports and group timeout, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Attempt to manipulate a remote ISP's outbound path by expecting an internal LOCAL_PREF value to be automatically carried over eBGP advertisements. It addresses the different topic BGP LOCAL_PREF within one autonomous system, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).