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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 BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

This option proposes: Distinguish EVPN control-plane route information and underlay forwarding when analyzing a VXLAN-enabled fabric. It addresses the different topic MP-BGP EVPN route types and forwarding separation, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

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 community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

This option proposes: Stateless address autoconfiguration uses advertised IPv6 prefix information and local interface identifier behavior, while Duplicate Address Detection probes for conflicts before enabling the address; DHCPv6 flags influence additional configuration modes. It addresses the different topic IPv6 SLAAC RA prefix and duplicate address detection, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

This option proposes: BGP AS_PATH records traversed autonomous systems, and an eBGP router ordinarily rejects a received route containing its own AS; prepending the local AS can influence some external path decisions but does not override every selection policy. It addresses the different topic BGP AS_PATH path-vector loop prevention, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

This option proposes: BGP path validity requires next-hop reachability; iBGP may preserve an eBGP-learned next hop, so a next-hop-self design can make that address reachable through the IGP where appropriate. It addresses the different topic BGP NEXT_HOP reachability and next-hop-self, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

This option proposes: Compare peer state transitions, source addresses, route to the peer, TCP 179 connectivity, local/remote AS settings and notification codes. It addresses the different topic BGP transport reachability and session states, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

This option proposes: Compare area addresses, supported router levels, L1 and L2 link-state databases and the attached-bit/default-route behavior toward external areas. It addresses the different topic IS-IS level one versus level two reachability, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

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 community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

That option concerns OSPF adjacency prerequisites and mismatched parameters. That follows from the targeted Recommended action: Use standard BGP communities and import/export policy to label route groups and apply intended traffic-engineering behavior.

This option proposes: The chosen BGP best path is explained by the actual earliest differentiating criterion rather than a single oversimplified metric. It addresses the different topic BGP route preference sequence and policy precedence, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

This option proposes: The selected BGP prefix has a resolvable next hop and traffic exits through the intended edge after the appropriate next-hop policy. It addresses the different topic BGP NEXT_HOP reachability and next-hop-self, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.). The better discriminating check for this case is: Inspect the community attached to a prefix, the matching community filter, permit or deny clauses and the route after policy application. The targeted correction is: Use standard BGP communities and import/export policy to label route groups and apply intended traffic-engineering behavior.

This option proposes: Treat a BGP route shown as received as sufficient evidence of packet forwarding when the NEXT_HOP has no route in the receiving router. It addresses the different topic BGP NEXT_HOP reachability and next-hop-self, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

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 community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

This option proposes: Assume two level-1-only IS-IS peers in different area IDs must always form a valid level-1 adjacency simply because their interfaces can ping. It addresses the different topic IS-IS area addresses and adjacency prerequisites, not the directly tested BGP community tagging and route-policy control failure in the stated incident (An operations team creates a route-policy that matches two communities but accidentally applies it in the import direction instead of export.).

This option proposes: Use standard BGP communities and import/export policy to label route groups and apply intended traffic-engineering behavior. It addresses the different topic BGP community tagging and route-policy control, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

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 MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

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 MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

This option proposes: A BGP network statement generally requires an appropriate matching route in the local routing table, whereas importing routes from other protocols uses an explicit redistribution mechanism; export policy can further restrict announcements. It addresses the different topic BGP route origin network and redistribution policy, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

This option proposes: BGP best-path selection evaluates eligibility and multiple attributes in a defined order; higher-stage policy attributes such as LOCAL_PREF can outweigh AS_PATH length, and later tie-breakers apply only as needed. It addresses the different topic BGP route preference sequence and policy precedence, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

This option proposes: A stub area blocks type 5 external LSAs and receives an appropriate default through its ABR; a totally stubby configuration additionally suppresses most inter-area summaries and is incompatible with certain topology roles. It addresses the different topic Stub and totally stub area restrictions, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

This option proposes: Review each node sequence, if-match clauses, apply actions and import/export attachment for the affected routing session. It addresses the different topic Route-policy node and filtering direction, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

This option proposes: Inspect the community attached to a prefix, the matching community filter, permit or deny clauses and the route after policy application. It addresses the different topic BGP community tagging and route-policy control, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

This option proposes: Inspect the received AS_PATH, origin AS, eBGP neighbor AS, policy additions and route-selection evidence before changing prepend counts. It addresses the different topic BGP AS_PATH path-vector loop prevention, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.). The better discriminating check for this case is: Compare received EVPN route type, route target/import rules, VNI mapping, VTEP addresses and underlay route resolution. The targeted correction is: Distinguish EVPN control-plane route information and underlay forwarding when analyzing a VXLAN-enabled fabric.

That option concerns BGP MED interpretation between neighboring autonomous systems. That follows from the targeted action: Distinguish EVPN control-plane route information and underlay forwarding when analyzing a VXLAN-enabled fabric.

That option concerns BGP route reflector and cluster loop prevention. That follows from the targeted action: Distinguish EVPN control-plane route information and underlay forwarding when analyzing a VXLAN-enabled fabric.

That option concerns IS-IS designated intermediate system and pseudonode. That follows from the targeted action: Distinguish EVPN control-plane route information and underlay forwarding when analyzing a VXLAN-enabled fabric.

This option proposes: Compare received iBGP routes to the same prefix, LOCAL_PREF values, policy application points and next-hop reachability across edge routers. It addresses the different topic BGP LOCAL_PREF within one autonomous system, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.). The better discriminating check for this case is: Compare received EVPN route type, route target/import rules, VNI mapping, VTEP addresses and underlay route resolution. The targeted correction is: Distinguish EVPN control-plane route information and underlay forwarding when analyzing a VXLAN-enabled fabric.

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 MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

This option proposes: Ensure consistent MST region name, revision and VLAN-to-instance mapping before expecting switches to share the same spanning-tree instance topology. It addresses the different topic MSTP region and VLAN-to-instance mappings, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (Two leaf switches exchange EVPN Type 2 MAC/IP advertisements, yet overlay hosts cannot communicate because the underlay route to the remote VTEP is missing.).

This option proposes: Check the MED value and the policy context before using BGP advertisements to suggest which entry link another AS should prefer. It addresses the different topic BGP MED interpretation between neighboring autonomous systems, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (A tenant's Type 5 prefix appears in the BGP EVPN table but is not imported into the intended service VRF because route targets do not match.).

This option proposes: Diagnose a multicast drop by checking reverse path forwarding against the packet's source rather than only validating the destination group. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested MP-BGP EVPN route types and forwarding separation failure in the stated incident (A tenant's Type 5 prefix appears in the BGP EVPN table but is not imported into the intended service VRF because route targets do not match.).

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 MP-BGP EVPN route types and forwarding separation failure in the stated incident (A tenant's Type 5 prefix appears in the BGP EVPN table but is not imported into the intended service VRF because route targets do not match.).