Juniper JN0-364 Questions & Answers

Account for GRE/IP header overhead in tunnel MTU and path-MTU handling, then test large representative packets. Its normal acceptance signal would be maximum expected encapsulated packets cross the tunnel without fragmentation blackholes or oversized drop counters. Here the deciding check is different: packets to the remote outer endpoint resolve through an ordinary underlay route and GRE probes reach the peer.

Add an approved encryption layer such as IPsec when confidentiality is required, while retaining GRE only if needed for routing encapsulation. That could help in a case involving GRE confidentiality limitation. This failure instead depends on GRE endpoint underlay routing; GRE encapsulates packets between outer IP endpoints; the underlay must route the outer destination before inner traffic can succeed.

Configure and verify compatible protocol graceful-restart capability and planned helper behavior between neighbors. Its normal acceptance signal would be during a controlled routing restart, participating neighbors retain forwarding state only for the permitted grace interval and then converge correctly. Here the deciding check is different: packets to the remote outer endpoint resolve through an ordinary underlay route and GRE probes reach the peer.

Check forwarding-table next-hop sets and multi-flow traffic after any export-policy or path-cost change. The monitored boundary differs from generated route qualified next hop, so the original weakness might reappear unnoticed. Generated routes can derive their next-hop behavior from qualifying contributing routes, unlike aggregate discard summaries.

Monitor hidden BGP routes and next-hop resolution after IGP or route-reflector changes. The monitored boundary differs from generated route qualified next hop, so the original weakness might reappear unnoticed. Generated routes can derive their next-hop behavior from qualifying contributing routes, unlike aggregate discard summaries.

This is a useful guard against filter-based forwarding table selection, but it is not scoped to the observed generated route qualified next hop failure. An appropriate test would show that the generated route becomes active when eligible contributors exist and forwards through the intended resolved contributing next hop.

The affected customer's lookup uses the intended instance RIB and reaches only the destinations deliberately made available to that instance. That establishes routing instance separation rather than a repaired equal-cost forwarding flow hashing path. The reported failure still requires this evidence: the forwarding table contains the intended next-hop set and several independent flows distribute across healthy equal-cost paths.

The check is meaningful for static route next-hop resolution, but it does not prove that equal-cost forwarding flow hashing was repaired. Equal routing candidates do not prove the forwarding engine is using ECMP; Junos load-balancing policy and flow hashing determine installed next hops.

Both IPv4 endpoint paths are reachable and IPv6 packets traverse the encapsulated link end to end. It would validate a separate IPv6 over IPv4 tunnel underlay operation, not the change needed here. Confirm instead that the forwarding table contains the intended next-hop set and several independent flows distribute across healthy equal-cost paths.

BFD provides rapid bidirectional path liveness detection; it triggers routing response but is not by itself a replacement route. That describes BFD fast failure detection, whereas the observed symptoms are caused by IPv6 static next-hop scope; it does not predict the reported behavior.

IPv6 Neighbor Discovery uses ICMPv6 to resolve on-link next hops; blocking it disrupts forwarding even if static routes exist. That describes IPv6 neighbor discovery filtering, whereas the observed symptoms are caused by IPv6 static next-hop scope; it does not predict the reported behavior.

MP-BGP requires the appropriate address-family capability and route processing; an Established IPv4 BGP session alone does not carry IPv6 NLRI. Those conditions do not account for the specific IPv6 static next-hop scope problem reported by Oakline Utilities.

Audit network type against actual link topology during edge circuit deployment. That ongoing check is for OSPF point-to-point topology; it would not reliably detect recurrence of OSPF area identity mismatch. OSPF area identity is part of neighbor compatibility, and mismatched area membership prevents formation of the intended adjacency.

Validate MST digest and instance mapping consistency as part of configuration review. That ongoing check is for MSTP region consistency; it would not reliably detect recurrence of OSPF area identity mismatch. OSPF area identity is part of neighbor compatibility, and mismatched area membership prevents formation of the intended adjacency.

The control protects stable OSPF router identifier. It does not establish the ongoing OSPF area identity mismatch behavior required in this network. OSPF area identity is part of neighbor compatibility, and mismatched area membership prevents formation of the intended adjacency.

Check forwarding-table next-hop sets and multi-flow traffic after any export-policy or path-cost change. The monitored boundary differs from routing instance separation, so the original weakness might reappear unnoticed. Routing instances maintain separate routing and forwarding contexts; entries in one RIB do not automatically appear in another.

Include reserved-prefix and martian-route validation in route import audits and configuration-change tests. The monitored boundary differs from routing instance separation, so the original weakness might reappear unnoticed. Routing instances maintain separate routing and forwarding contexts; entries in one RIB do not automatically appear in another.

This is a useful guard against EBGP multihop reachability, but it is not scoped to the observed routing instance separation failure. An appropriate test would show that the affected customer's lookup uses the intended instance RIB and reaches only the destinations deliberately made available to that instance.

Every router has a distinct planned router ID and the LSDB tracks the appropriate originating router consistently. It would validate a separate stable OSPF router identifier operation, not the change needed here. Confirm instead that the two peers form a Full point-to-point adjacency without a broadcast-segment DR election.

This measurement tests OSPF area identity mismatch; it cannot distinguish success from failure for the observed OSPF point-to-point topology condition. OSPF point-to-point interfaces do not use a DR or BDR; this differs from a shared multiaccess Ethernet network.

This measurement tests IS-IS adjacency circuit level; it cannot distinguish success from failure for the observed OSPF point-to-point topology condition. OSPF point-to-point interfaces do not use a DR or BDR; this differs from a shared multiaccess Ethernet network.

IPv6 link-local next hops are interface-scoped; a bare link-local address can be insufficient to identify the outgoing link. That describes IPv6 static next-hop scope, whereas the observed symptoms are caused by provider Q-in-Q tagging; it does not predict the reported behavior.

Junos interface VLAN tagging mode and logical-unit encapsulation must match received frame format for successful delivery. That describes flexible VLAN encapsulation alignment, whereas the observed symptoms are caused by provider Q-in-Q tagging; it does not predict the reported behavior.

Although integrated routing and bridging needs this consideration, the failure at issue has a different cause. Q-in-Q carries an additional provider VLAN tag around customer-tagged traffic to isolate services with overlapping customer VLAN numbers.

Review IS-IS export policies against owner-approved prefix and origin criteria after service changes. That ongoing check is for IS-IS route redistribution policy; it would not reliably detect recurrence of IS-IS NET and system ID. The IS-IS NET encodes area membership and system identity, which must be consistent with the planned level and unique per node.

Audit L1/L2 levels, attached-bit behavior, and approved route leaks after backbone changes. That ongoing check is for IS-IS L1 and L2 reachability; it would not reliably detect recurrence of IS-IS NET and system ID. The IS-IS NET encodes area membership and system identity, which must be consistent with the planned level and unique per node.

This is a useful guard against RSTP loop protection, but it is not scoped to the observed IS-IS NET and system ID failure. An appropriate test would show that neighbor state and system IDs show unique routers, and Level 1 adjacency establishes only among compatible area peers.

Enable and inspect the relevant IS-IS IPv6 address-family reachability advertisements and verify eligible routes. This addresses IS-IS IPv6 topology TLVs, but the reported symptoms arise from OSPFv3 IPv6 neighbor reachability. For this case, verify instead that the expected OSPFv3 neighbor reaches Full and IPv6 routes appear with intended next hops.

Allow the required scoped ICMPv6 neighbor discovery exchanges and confirm neighbor cache resolution. Its normal acceptance signal would be neighbor Solicitation and Advertisement complete and the destination's link-layer neighbor entry becomes usable. Here the deciding check is different: the expected OSPFv3 neighbor reaches Full and IPv6 routes appear with intended next hops.

Use loop protection on appropriate nondesignated interfaces and verify the safe state during missing-BPDU events. Its normal acceptance signal would be the impacted non-designated port stays protected while BPDUs are absent and returns only after control-plane health is restored. Here the deciding check is different: the expected OSPFv3 neighbor reaches Full and IPv6 routes appear with intended next hops.

BGP import policy governs received routes and export policy governs outbound advertisements; changing the wrong direction cannot enforce the intended boundary. Those conditions do not account for the specific OSPF interface metric selection problem reported by Beacon Data Exchange.

Although OSPF point-to-point topology needs this consideration, the failure at issue has a different cause. OSPF chooses lowest-cost paths computed from link-state topology; a Full adjacency alone does not guarantee the desired route preference.

This principle matters when troubleshooting OSPF area LSA propagation, but using it here mistakes a different failure mode for OSPF interface metric selection. The relevant distinction is: OSPF chooses lowest-cost paths computed from link-state topology; a Full adjacency alone does not guarantee the desired route preference.