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This option proposes: Analyze Virtual Router Redundancy Protocol master election using priorities and the virtual router ID instead of a router's physical interface address alone. It addresses the different topic VRRP master election priority and tie breaks, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

This option proposes: Explain the DIS role on broadcast IS-IS circuits and why it differs from an OSPF DR/BDR election. It addresses the different topic IS-IS designated intermediate system and pseudonode, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

This option proposes: Investigate routing decisions by checking longest destination-prefix match before comparing preferences among competing routes for that same prefix. It addresses the different topic Longest prefix match and route preferences, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

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 Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

This option proposes: A stateful firewall tracks valid connection context and can permit related return traffic based on session state; network ACLs may filter packets independently without the same stateful application tracking. It addresses the different topic Stateful firewall sessions versus basic packet ACL filtering, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

This option proposes: In controller-managed WLANs an AP typically discovers and establishes control communication with the AC using CAPWAP, while local or centralized data forwarding depends on the chosen design and correct VLAN mapping. It addresses the different topic Large campus WLAN AC AP and CAPWAP architecture, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

This option proposes: Inspect traffic classifier matches, policy routing next-hop eligibility, egress statistics and the normal destination route that would otherwise apply. It addresses the different topic Policy-based routing versus destination routing, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

This option proposes: Inspect the destination address, matching installed prefixes, their mask lengths, route sources, next-hop resolution and the forwarding decision. It addresses the different topic Longest prefix match and route preferences, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

This option proposes: Compare matched source/destination NAT rule, translated session tuple, security-zone permission and upstream route to the translated address. It addresses the different topic Huawei firewall NAT and address translation context, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

That option concerns Longest prefix match and route preferences. That follows from the targeted action: Diagnose a packet-forwarding discrepancy by separating control-plane routes recorded in the RIB from hardware or software forwarding entries installed in the FIB.

That option concerns OSPF backbone connectivity and virtual link design. That follows from the targeted action: Diagnose a packet-forwarding discrepancy by separating control-plane routes recorded in the RIB from hardware or software forwarding entries installed in the FIB.

That option concerns IS-IS area addresses and adjacency prerequisites. That follows from the targeted action: Diagnose a packet-forwarding discrepancy by separating control-plane routes recorded in the RIB from hardware or software forwarding entries installed in the FIB.

This option proposes: Inspect the destination address, matching installed prefixes, their mask lengths, route sources, next-hop resolution and the forwarding decision. It addresses the different topic Longest prefix match and route preferences, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.). The better discriminating check for this case is: Compare the best route, recursive next-hop resolution, forwarding entry and actual egress interface for the same destination prefix.

This option proposes: Validate resilient AC roles and per-user access decisions when WLAN controller failure or endpoint authorization affects service. It addresses the different topic WLAN controller redundancy and NAC integration, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

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 Network forwarding planes RIB versus FIB failure in the stated incident (A core switch learns a remote subnet in OSPF, yet packets toward it are dropped because the route's recursive next hop has no usable forwarding adjacency.).

This option proposes: Investigate routing decisions by checking longest destination-prefix match before comparing preferences among competing routes for that same prefix. It addresses the different topic Longest prefix match and route preferences, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

This option proposes: Analyze BGP best-path choices in a specified platform and release before deciding that the shortest AS_PATH alone always wins. It addresses the different topic BGP route preference sequence and policy precedence, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

This option proposes: Check OSPF area type before attempting to import external routes into an area intended to suppress route detail. It addresses the different topic Stub and totally stub area restrictions, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

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 Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

This option proposes: IS-IS uses CLNS-based network entities and level-specific hellos; level-1 neighbors normally require compatible area membership, while level-2 adjacencies have different area constraints and still need link and authentication compatibility. It addresses the different topic IS-IS area addresses and adjacency prerequisites, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

This option proposes: NAT rules change observed packet addresses under defined conditions, and a permitted security rule alone does not create a suitable translation mapping or solve upstream return routing. It addresses the different topic Huawei firewall NAT and address translation context, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

This option proposes: Inspect the destination address, matching installed prefixes, their mask lengths, route sources, next-hop resolution and the forwarding decision. It addresses the different topic Longest prefix match and route preferences, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

This option proposes: Compare the area link-state database, LSA type, advertising router, ABR reachability and route installation for the absent prefix. It addresses the different topic OSPF router network and summary LSA scope, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

This option proposes: Inspect OSPF neighbor states and interface detail on both ends, including area IDs, hello/dead intervals, network type and authentication settings. It addresses the different topic OSPF adjacency prerequisites and mismatched parameters, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

That option concerns SNMP manager polling traps and authenticated operation. That follows from the targeted Recommended action: Diagnose a packet-forwarding discrepancy by separating control-plane routes recorded in the RIB from hardware or software forwarding entries installed in the FIB.

That option concerns Longest prefix match and route preferences. That follows from the targeted Recommended action: Diagnose a packet-forwarding discrepancy by separating control-plane routes recorded in the RIB from hardware or software forwarding entries installed in the FIB.

That option concerns BGP route origin network and redistribution policy. That follows from the targeted Recommended action: Diagnose a packet-forwarding discrepancy by separating control-plane routes recorded in the RIB from hardware or software forwarding entries installed in the FIB.

This option proposes: Inspect the destination address, matching installed prefixes, their mask lengths, route sources, next-hop resolution and the forwarding decision. It addresses the different topic Longest prefix match and route preferences, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.). The better discriminating check for this case is: Compare the best route, recursive next-hop resolution, forwarding entry and actual egress interface for the same destination prefix.

This option proposes: Trace source or destination address translation separately from security policy when applications fail across a routed perimeter. It addresses the different topic Huawei firewall NAT and address translation context, not the directly tested Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).

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 Network forwarding planes RIB versus FIB failure in the stated incident (During a maintenance cutover an operator sees a static route in configuration but a line-card forwarding inspection shows an unresolved next hop.).