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This option proposes: Use AS_PATH to reason about external route propagation, loop prevention and intentional prepending effects. It addresses the different topic BGP AS_PATH path-vector loop prevention, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: Identify OSPF LSA types and their flooding scope before diagnosing missing intra-area or inter-area destinations. It addresses the different topic OSPF router network and summary LSA scope, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: Apply route-reflector client roles and loop-prevention attributes to an iBGP topology that must scale beyond a full mesh. It addresses the different topic BGP route reflector and cluster loop prevention, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: LOCAL_PREF is an intra-AS BGP path attribute, with larger values generally preferred at its stage of best-path selection; it is not normally advertised to eBGP neighbors. It addresses the different topic BGP LOCAL_PREF within one autonomous system, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: BGP communities carry policy markers that can be matched by participating peers, but the markers alone do not enforce filtering unless suitable route-policy rules recognize and act on them. It addresses the different topic BGP community tagging and route-policy control, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: WLAN roaming is a client transition between APs, and preserving service depends on consistent SSID/security configuration, mobility coordination and the chosen network architecture, not simply RF overlap. It addresses the different topic Wireless roaming mobility and session continuity, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: Compare candidate route validity, policy preferences, AS_PATH lengths, origins, MED, eBGP/iBGP learning mode and relevant platform-specific tie-break rules. It addresses the different topic BGP route preference sequence and policy precedence, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: Compare traffic patterns, device role, access-layer services, user or workload segmentation, resiliency goals and the underlying control-plane topology. It addresses the different topic Campus design versus data center fabric operational boundaries, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: Inspect route-reflector client configuration, ORIGINATOR_ID, CLUSTER_LIST and resulting prefixes at different iBGP clients. It addresses the different topic BGP route reflector and cluster loop prevention, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

That option concerns Longest prefix match and route preferences. That follows from the targeted Recommended action: Check the MED value and the policy context before using BGP advertisements to suggest which entry link another AS should prefer.

That option concerns BGP route reflector and cluster loop prevention. That follows from the targeted Recommended action: Check the MED value and the policy context before using BGP advertisements to suggest which entry link another AS should prefer.

That option concerns BGP transport reachability and session states. That follows from the targeted Recommended action: Check the MED value and the policy context before using BGP advertisements to suggest which entry link another AS should prefer.

This option proposes: Verify NSSA area behavior and type 7-to-type 5 translation when redistributing an external prefix inside a non-backbone area. It addresses the different topic NSSA type seven translation and default routing, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: Compare candidate route validity, policy preferences, AS_PATH lengths, origins, MED, eBGP/iBGP learning mode and relevant platform-specific tie-break rules. It addresses the different topic BGP route preference sequence and policy precedence, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.). The better discriminating check for this case is: Inspect candidate routes' neighboring AS, MED values, other higher-priority attributes and local comparison configuration.

This option proposes: Diagnose a packet-forwarding discrepancy by separating control-plane routes recorded in the RIB from hardware or software forwarding entries installed in the FIB. It addresses the different topic Network forwarding planes RIB versus FIB, not the directly tested BGP MED interpretation between neighboring autonomous systems failure in the stated incident (A multihomed company sets the same MED on both uplinks but observes traffic asymmetry caused by its partner's local routing policy.).

This option proposes: Troubleshoot BGP establishment by distinguishing TCP port 179 transport, peer configuration and OPEN capability negotiation. It addresses the different topic BGP transport reachability and session states, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

This option proposes: Use AS_PATH to reason about external route propagation, loop prevention and intentional prepending effects. It addresses the different topic BGP AS_PATH path-vector loop prevention, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

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 BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

This option proposes: MED is an optional nontransitive BGP attribute, with lower values typically favored when compared under applicable rules; it is often compared for routes from the same neighboring AS unless policy changes this behavior. It addresses the different topic BGP MED interpretation between neighboring autonomous systems, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

This option proposes: LOCAL_PREF is an intra-AS BGP path attribute, with larger values generally preferred at its stage of best-path selection; it is not normally advertised to eBGP neighbors. It addresses the different topic BGP LOCAL_PREF within one autonomous system, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

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 BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

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 BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

This option proposes: Inspect bridge IDs, selected root bridge, root-path costs, each port role and current alternate/discarding state. It addresses the different topic RSTP port roles and rapid convergence, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

This option proposes: Compare candidate route validity, policy preferences, AS_PATH lengths, origins, MED, eBGP/iBGP learning mode and relevant platform-specific tie-break rules. It addresses the different topic BGP route preference sequence and policy precedence, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

That option concerns BGP MED interpretation between neighboring autonomous systems. That follows from the targeted action: Investigate a BGP route that appears in a peer table but fails to install because its NEXT_HOP is unresolved.

That option concerns MP-BGP EVPN route types and forwarding separation. That follows from the targeted action: Investigate a BGP route that appears in a peer table but fails to install because its NEXT_HOP is unresolved.

That option concerns IPv6 SLAAC RA prefix and duplicate address detection. That follows from the targeted action: Investigate a BGP route that appears in a peer table but fails to install because its NEXT_HOP is unresolved.

This option proposes: Override all AS loop checks because a longer AS_PATH is said to be universally more attractive to every external BGP neighbor. It addresses the different topic BGP AS_PATH path-vector loop prevention, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

This option proposes: Declare that every OSPF external route uses only internal link-state cost and cannot carry a distinct ASBR-advertised metric. It addresses the different topic OSPF external LSAs and E1 versus E2 cost, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

This option proposes: Declare that setting MED to zero guarantees every Internet autonomous system will send traffic through that link regardless of local preference or AS_PATH. It addresses the different topic BGP MED interpretation between neighboring autonomous systems, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A campus route reflector passes an external prefix to branch iBGP routers, but their RIB rejects it because the upstream link's next hop is not known.).

This option proposes: Apply OSPF neighbor authentication and passive-interface policy without accidentally suppressing required route advertisements. It addresses the different topic OSPF interface security and passive network advertisement, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A network engineer changes next-hop-self at the eBGP edge and needs to confirm iBGP clients can now resolve the advertised prefix.).

This option proposes: Verify BGP network origination and import-route mechanisms before expecting a prefix to be advertised. It addresses the different topic BGP route origin network and redistribution policy, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A network engineer changes next-hop-self at the eBGP edge and needs to confirm iBGP clients can now resolve the advertised prefix.).

This option proposes: Use AS_PATH to reason about external route propagation, loop prevention and intentional prepending effects. It addresses the different topic BGP AS_PATH path-vector loop prevention, not the directly tested BGP NEXT_HOP reachability and next-hop-self failure in the stated incident (A network engineer changes next-hop-self at the eBGP edge and needs to confirm iBGP clients can now resolve the advertised prefix.).