Juniper JN0-364 Questions & Answers

Track IPv4 and IPv6 IS-IS reachability separately in dual-stack health checks. The monitored boundary differs from IPv6 static next-hop scope, so the original weakness might reappear unnoticed. IPv6 link-local next hops are interface-scoped; a bare link-local address can be insufficient to identify the outgoing link.

Guard tunnel outer endpoint routes against redistribution into the overlay routing table. That ongoing check is for GRE recursive route avoidance; it would not reliably detect recurrence of IPv6 static next-hop scope. IPv6 link-local next hops are interface-scoped; a bare link-local address can be insufficient to identify the outgoing link.

This is a useful guard against IPv6 neighbor discovery filtering, but it is not scoped to the observed IPv6 static next-hop scope failure. An appropriate test would show that the intended IPv6 destination has an active route with a resolved next hop and working egress interface.

The proposal changes integrated routing and bridging; that is not the failure isolated by the facts. It could leave flexible VLAN encapsulation alignment unresolved even if its own test passed. Junos interface VLAN tagging mode and logical-unit encapsulation must match received frame format for successful delivery. Applied here, the relevant facts are: After a provider port migration, stacked-tag frames drop because the logical units do not match the expected flexible VLAN tag form. The question asks which focused engineering action would best correct the fault.

Enable the supported BPDU protection behavior on designated edge ports so unexpected BPDUs trigger a controlled protective response. This addresses RSTP edge BPDU protection, but the reported symptoms arise from flexible VLAN encapsulation alignment. For this case, verify instead that the correct single- and double-tagged service units receive traffic matching their configured VLAN identifiers.

The proposal changes virtual-switch instance isolation; that is not the failure isolated by the facts. It could leave flexible VLAN encapsulation alignment unresolved even if its own test passed. Junos interface VLAN tagging mode and logical-unit encapsulation must match received frame format for successful delivery.

This is a useful guard against IS-IS adjacency circuit level, but it is not scoped to the observed LACP aggregation consistency failure. An appropriate test would show that every intended member joins the same aggregation and distributes frames according to the approved LAG hash behavior.

Test forwarding, bridge MAC state, and protocol-neighbor continuity separately during redundant Routing Engine failover drills. That ongoing check is for GRES preserves forwarding not protocols; it would not reliably detect recurrence of LACP aggregation consistency. LACP aggregates only compatible negotiated member links; physical Up state alone does not prove active bundle participation.

Test BFD session negotiation and routing reaction times during controlled failures. That ongoing check is for BFD fast failure detection; it would not reliably detect recurrence of LACP aggregation consistency. LACP aggregates only compatible negotiated member links; physical Up state alone does not prove active bundle participation.

Equal routing candidates do not prove the forwarding engine is using ECMP; Junos load-balancing policy and flow hashing determine installed next hops. Those conditions do not account for the specific RIB group route sharing problem reported by Maplewood Exchange.

An aggregate route is conditional on active contributing routes and normally uses a discard or reject next hop to avoid creating a forwarding loop. That describes aggregate route contributor, whereas the observed symptoms are caused by RIB group route sharing; it does not predict the reported behavior.

MPLS forwards using labels: ingress commonly pushes labels, intermediate LSRs swap them, and the egress removes the remaining label. Those conditions do not account for the specific RIB group route sharing problem reported by Maplewood Exchange.

The control protects GRE confidentiality limitation. It does not establish the ongoing GRE recursive route avoidance behavior required in this network. A tunnel's transport destination must not depend on routing through that same tunnel; recursion defeats the encapsulation path.

The control protects GRE endpoint underlay routing. It does not establish the ongoing GRE recursive route avoidance behavior required in this network. A tunnel's transport destination must not depend on routing through that same tunnel; recursion defeats the encapsulation path.

Rehearse planned root-link failures and verify alternate-port transitions and absence of loop symptoms. That ongoing check is for RSTP alternate port reconvergence; it would not reliably detect recurrence of GRE recursive route avoidance. A tunnel's transport destination must not depend on routing through that same tunnel; recursion defeats the encapsulation path.

The check is meaningful for LACP aggregation consistency, but it does not prove that RSTP loop protection was repaired. Loop protection protects non-designated ports against false transition to forwarding when expected BPDUs disappear.

This measurement tests RSTP alternate port reconvergence; it cannot distinguish success from failure for the observed RSTP loop protection condition. Loop protection protects non-designated ports against false transition to forwarding when expected BPDUs disappear.

This measurement tests RSTP root protection; it cannot distinguish success from failure for the observed RSTP loop protection condition. Loop protection protects non-designated ports against false transition to forwarding when expected BPDUs disappear.

Validate accepted tag stacks and logical-unit counters when deploying a multi-service port. That ongoing check is for flexible VLAN encapsulation alignment; it would not reliably detect recurrence of IBGP route reflection. Ordinary iBGP does not readvertise iBGP-learned routes to another iBGP peer; route reflectors provide a controlled exception.

This is a useful guard against BGP import export control, but it is not scoped to the observed IBGP route reflection failure. An appropriate test would show that authorized clients receive the expected reflected iBGP paths and preserve appropriate originator or cluster-loop protection.

The control protects EBGP multihop reachability. It does not establish the ongoing IBGP route reflection behavior required in this network. Ordinary iBGP does not readvertise iBGP-learned routes to another iBGP peer; route reflectors provide a controlled exception.

This principle matters when troubleshooting virtual-switch instance isolation, but using it here mistakes a different failure mode for integrated routing and bridging. The relevant distinction is: IRB provides an L3 interface for a Layer 2 VLAN bridge domain; MAC learning alone cannot perform inter-subnet routing.

LDP discovery and session setup are distinct; a transport TCP connection must be reachable after hello discovery. That describes LDP transport address reachability, whereas the observed symptoms are caused by integrated routing and bridging; it does not predict the reported behavior.

Q-in-Q carries an additional provider VLAN tag around customer-tagged traffic to isolate services with overlapping customer VLAN numbers. Those conditions do not account for the specific integrated routing and bridging problem reported by Alderbrook Transit.

Apply a scoped OSPF export policy to originate only the approved active source prefix and confirm the receiving routers learn it. This addresses OSPF external route export, but the reported symptoms arise from EBGP multihop reachability. For this case, verify instead that the intended multi-hop peer establishes while IP reachability and any required loopback-source configuration are correct.

Correct the locally expected peer AS and actual neighbor AS identity and validate the BGP OPEN exchange. That could help in a case involving BGP ASN and OPEN negotiation. This failure instead depends on EBGP multihop reachability; EBGP sessions to nonadjacent neighbors need suitable multihop TTL and transport reachability; routing reachability alone can be insufficient.

The proposal changes BGP import export control; that is not the failure isolated by the facts. It could leave EBGP multihop reachability unresolved even if its own test passed. EBGP sessions to nonadjacent neighbors need suitable multihop TTL and transport reachability; routing reachability alone can be insufficient.

This measurement tests NSR protocol state replication; it cannot distinguish success from failure for the observed RSTP root protection condition. Root protection blocks acceptance of an unexpected superior root across designated boundary ports; it is not the same as BPDU edge protection.

This measurement tests RSTP alternate port reconvergence; it cannot distinguish success from failure for the observed RSTP root protection condition. Root protection blocks acceptance of an unexpected superior root across designated boundary ports; it is not the same as BPDU edge protection.

An unexpected BPDU causes the intended protective state and operations receive a traceable port event. It would validate a separate RSTP edge BPDU protection operation, not the change needed here. Confirm instead that the approved root remains root despite inferior-site superior-BPDU injection, and the boundary behaves as designed.

This principle matters when troubleshooting multiprotocol BGP IPv6 AFI, but using it here mistakes a different failure mode for IS-IS IPv6 topology TLVs. The relevant distinction is: IS-IS can carry IPv6 topology and prefix information using appropriate TLVs; an IPv4 route table is not a substitute.

This principle matters when troubleshooting MPLS label push swap pop, but using it here mistakes a different failure mode for IS-IS IPv6 topology TLVs. The relevant distinction is: IS-IS can carry IPv6 topology and prefix information using appropriate TLVs; an IPv4 route table is not a substitute.

Although IPv6 neighbor discovery filtering needs this consideration, the failure at issue has a different cause. IS-IS can carry IPv6 topology and prefix information using appropriate TLVs; an IPv4 route table is not a substitute.