Juniper JN0-650 Practice Test 16
Question 150
A 10-Gbps link and a 100-Gbps link appear to receive indistinguishable default OSPF cost. Which configuration or operational step BEST meets the stated requirement?
- Raise one link bandwidth value in a monitoring chart without checking OSPF cost calculation.
- Configure matching supported OSPF authentication parameters on both neighbors.
- Use a consistent OSPF reference-bandwidth policy across the intended routing domain.
- Tune eligible OSPF interface priority and plan an explicit election event where required.
Explanation
Correct Answer
C:Use a consistent OSPF reference-bandwidth policy across the intended routing domain. OSPF automatic cost can require reference-bandwidth adjustment as interfaces become faster. The expected validation is that faster links receive the planned comparative metrics in the routing database.
Incorrect Answers
A:Raise one link bandwidth value in a monitoring chart without checking OSPF cost calculation. This is a risky or ineffective shortcut for OSPF reference bandwidth and high-speed links. Inconsistent reference bandwidth across routers may distort intended route decisions.
B:Configure matching supported OSPF authentication parameters on both neighbors. This addresses OSPF authentication key or algorithm rather than the required OSPF reference bandwidth and high-speed links decision. OSPF automatic cost can require reference-bandwidth adjustment as interfaces become faster.
D:Tune eligible OSPF interface priority and plan an explicit election event where required. This addresses OSPF designated router election broadcast LAN rather than the required OSPF reference bandwidth and high-speed links decision. OSPF automatic cost can require reference-bandwidth adjustment as interfaces become faster.
Question 151
An access-to-distribution link passes management traffic but drops a tagged production VLAN. Select TWO statements that correctly combine the 802.1Q trunk allowed VLANs implementation, its evidence, or its governing principle.
- Validate compatible VSTP participation per VLAN and consistent trunk membership.
- Expected tagged VLAN traffic traverses the trunk while unapproved VLANs remain blocked.
- Configure correct trunk mode VLAN membership and tagging at both switch interfaces.
- Assign an IPv4 default route and assume the missing VLAN is automatically allowed on the trunk.
- Identify MAC learning state and remediate loops or incorrect topology.
Explanation
Correct Answers
B:Expected tagged VLAN traffic traverses the trunk while unapproved VLANs remain blocked. This is direct observable evidence for 802.1Q trunk allowed VLANs.
C:Configure correct trunk mode VLAN membership and tagging at both switch interfaces. This is the intended implementation action for 802.1Q trunk allowed VLANs.
Incorrect Answers
A:Validate compatible VSTP participation per VLAN and consistent trunk membership. This belongs to VSTP interoperation and VLAN tagging, not the specified 802.1Q trunk allowed VLANs operation. IEEE 802.1Q tags distinguish VLAN traffic across a common trunk.
D:Assign an IPv4 default route and assume the missing VLAN is automatically allowed on the trunk. This would not be an appropriate 802.1Q trunk allowed VLANs decision. Missing tagged membership creates silent Layer 2 reachability gaps.
E:Identify MAC learning state and remediate loops or incorrect topology. This belongs to Ethernet MAC learning and flooding, not the specified 802.1Q trunk allowed VLANs operation. IEEE 802.1Q tags distinguish VLAN traffic across a common trunk.
Question 152
A guest uplink sends bursts far above its allowed traffic contract. Which configuration or operational step BEST meets the stated requirement?
- Set egress shaping to the supported carrier rate on the correct interface or queue.
- Configure a supported traffic policer with appropriate rate and burst allowance.
- Attach a BGP community to packets and call it an interface policer.
- Configure appropriate rewrite rules mapping forwarding class and PLP to egress DSCP.
Explanation
Correct Answer
B:Configure a supported traffic policer with appropriate rate and burst allowance. A policer meters traffic and may drop or remark traffic exceeding its limits. The expected validation is that excess traffic is treated according to policy and compliant traffic continues.
Incorrect Answers
A:Set egress shaping to the supported carrier rate on the correct interface or queue. This addresses Junos egress shaping rate rather than the required Junos ingress policer rate limit decision. A policer meters traffic and may drop or remark traffic exceeding its limits.
C:Attach a BGP community to packets and call it an interface policer. This is a risky or ineffective shortcut for Junos ingress policer rate limit. Wrong burst values can create unnecessary packet loss for permitted applications.
D:Configure appropriate rewrite rules mapping forwarding class and PLP to egress DSCP. This addresses DSCP egress rewrite rules rather than the required Junos ingress policer rate limit decision. A policer meters traffic and may drop or remark traffic exceeding its limits.
Question 153
OSPFv3 neighbors reach Full but an IPv6 LAN prefix is absent from other routers. After deploying the recommended OSPFv3 IPv6 prefix advertisement change, which result MOST directly verifies success?
- Packet counters show EF-marked traffic assigned to approved forwarding class and queue.
- Database-description exchange completes and neighbor reaches Full.
- Intended inet6 routes appear on remote Junos nodes with resolvable next hops.
- Active routes prefer the expected lowest cumulative OSPF metric.
Explanation
Correct Answer
C:Intended inet6 routes appear on remote Junos nodes with resolvable next hops. This is the directly observable outcome for OSPFv3 IPv6 prefix advertisement. OSPFv3 separates neighbor topology information from IPv6 prefix dissemination.
Incorrect Answers
A:Packet counters show EF-marked traffic assigned to approved forwarding class and queue. This validates Junos ingress BA DSCP classifier but does not directly demonstrate the required OSPFv3 IPv6 prefix advertisement result. OSPFv3 separates neighbor topology information from IPv6 prefix dissemination.
B:Database-description exchange completes and neighbor reaches Full. This validates OSPF interface MTU mismatch but does not directly demonstrate the required OSPFv3 IPv6 prefix advertisement result. OSPFv3 separates neighbor topology information from IPv6 prefix dissemination.
D:Active routes prefer the expected lowest cumulative OSPF metric. This validates OSPF path cost selection but does not directly demonstrate the required OSPFv3 IPv6 prefix advertisement result. OSPFv3 separates neighbor topology information from IPv6 prefix dissemination.
Question 154
An import policy unexpectedly accepts a long private prefix because an early term matches broadly. Which technical principle BEST explains the Junos BGP policy term matching decision?
- Import changes received-route eligibility while export governs what is sent to peers.
- Junos routing policy evaluates ordered terms and control-flow actions.
- VXLAN data plane depends on routable VTEP endpoints independent of EVPN MAC learning.
- Graceful restart preserves temporary forwarding state but is not unlimited reachability assurance.
Explanation
Correct Answer
B:Junos routing policy evaluates ordered terms and control-flow actions. In this situation, the relevant action is to implement ordered Junos policy terms with prefix match and explicit accept or reject decisions.
Incorrect Answers
A:Import changes received-route eligibility while export governs what is sent to peers. That principle is related to BGP import versus export policy direction, not the main Junos BGP policy term matching choice. An overly general term can prevent subsequent protective terms from being reached.
C:VXLAN data plane depends on routable VTEP endpoints independent of EVPN MAC learning. That principle is related to VXLAN VTEP loopback underlay route, not the main Junos BGP policy term matching choice. An overly general term can prevent subsequent protective terms from being reached.
D:Graceful restart preserves temporary forwarding state but is not unlimited reachability assurance. That principle is related to BGP graceful restart session continuity, not the main Junos BGP policy term matching choice. An overly general term can prevent subsequent protective terms from being reached.
Question 155
A Junos eBGP session remains Active because each router expects the wrong remote autonomous system. Which configuration or operational step BEST meets the stated requirement?
- Change an OSPF cost and assume it repairs the remote AS mismatch.
- Configure matching local and peer AS settings and verify session transport.
- Apply supported route-flap damping only where its stability tradeoff is justified.
- Add approved BGP community tags and match them in explicit import or export policies.
Explanation
Correct Answer
B:Configure matching local and peer AS settings and verify session transport. BGP OPEN exchange checks autonomous-system identity and capability compatibility. The expected validation is that bGP reaches Established with the expected local and remote ASN and prefix families.
Incorrect Answers
A:Change an OSPF cost and assume it repairs the remote AS mismatch. This is a risky or ineffective shortcut for BGP eBGP peer AS and local identity. Wrong peer-AS values cause BGP OPEN rejection despite TCP connectivity.
C:Apply supported route-flap damping only where its stability tradeoff is justified. This addresses BGP route damping flap penalty rather than the required BGP eBGP peer AS and local identity decision. BGP OPEN exchange checks autonomous-system identity and capability compatibility.
D:Add approved BGP community tags and match them in explicit import or export policies. This addresses BGP communities tagging routing intent rather than the required BGP eBGP peer AS and local identity decision. BGP OPEN exchange checks autonomous-system identity and capability compatibility.
Question 156
A phone-plus-PC access port treats both devices' DSCP as equally trusted. Select TWO statements that correctly combine the QoS trust boundary at campus edge implementation, its evidence, or its governing principle.
- Configure suitable RED or WRED drop profiles and map PLP to planned thresholds.
- Configure a supported multifield classifier or ingress firewall filter matching relevant flow fields.
- Untrusted workstation EF markings cannot steal the intended voice queue.
- Trust all DSCP on every public access port because users may have telephony apps.
- Classify or remark untrusted edge traffic while retaining appropriate trusted phone service.
Explanation
Correct Answers
C:Untrusted workstation EF markings cannot steal the intended voice queue. This is direct observable evidence for QoS trust boundary at campus edge.
E:Classify or remark untrusted edge traffic while retaining appropriate trusted phone service. This is the intended implementation action for QoS trust boundary at campus edge.
Incorrect Answers
A:Configure suitable RED or WRED drop profiles and map PLP to planned thresholds. This belongs to RED WRED drop profile thresholds, not the specified QoS trust boundary at campus edge operation. A CoS trust boundary defines whose markings should be honored.
B:Configure a supported multifield classifier or ingress firewall filter matching relevant flow fields. This belongs to Junos multifield firewall filter classification, not the specified QoS trust boundary at campus edge operation. A CoS trust boundary defines whose markings should be honored.
D:Trust all DSCP on every public access port because users may have telephony apps. This would not be an appropriate QoS trust boundary at campus edge decision. Trusting all edge markings lets ordinary traffic claim priority service.
Question 157
During an operational risk review, this situation is reported: A scheduler uses tiny buffers for bursty business traffic. If the underlying control is neglected, which failure would MOST directly follow?
- Treating every packet as identical PLP may defeat differentiated congestion policy.
- An overly permissive export can leak private or unreachable prefixes across the domain.
- Excessively small buffers cause avoidable drops while overlarge buffers increase delay.
- Trusting all edge markings lets ordinary traffic claim priority service.
Explanation
Correct Answer
C:Excessively small buffers cause avoidable drops while overlarge buffers increase delay. Egress buffers absorb short bursts but cannot compensate for persistent overload. A useful corrective investigation is to compare queue occupancy drops and latency across representative bursts.
Incorrect Answers
A:Treating every packet as identical PLP may defeat differentiated congestion policy. This is a Packet loss priority PLP marking failure pattern, not the primary Queue buffer-size allocation failure in this case. Egress buffers absorb short bursts but cannot compensate for persistent overload.
B:An overly permissive export can leak private or unreachable prefixes across the domain. This is a OSPF external export policy redistribution failure pattern, not the primary Queue buffer-size allocation failure in this case. Egress buffers absorb short bursts but cannot compensate for persistent overload.
D:Trusting all edge markings lets ordinary traffic claim priority service. This is a QoS trust boundary at campus edge failure pattern, not the primary Queue buffer-size allocation failure in this case. Egress buffers absorb short bursts but cannot compensate for persistent overload.
Question 158
A handset is in the data VLAN because no LLDP-MED network policy is advertised. Which next investigation or correction is MOST appropriate?
- Set the switch system-name to Voice and claim LLDP-MED policy is automatically configured.
- Compare PoE state and cable diagnostics on known-good versus failing links.
- Inspect LLDP-MED advertisements and tagged phone frames on the link.
- Inspect show poe interface and total allocated versus available watts.
Explanation
Correct Answer
C:Inspect LLDP-MED advertisements and tagged phone frames on the link. This checks whether the handset receives voice VLAN policy and tags voice frames as intended.
Incorrect Answers
A:Set the switch system-name to Voice and claim LLDP-MED policy is automatically configured. That bypass leaves the LLDP-MED voice network policy issue unresolved. Basic LLDP neighbor discovery alone may not advertise the required voice VLAN.
B:Compare PoE state and cable diagnostics on known-good versus failing links. That check applies chiefly to PoE fault isolation and cable pair, not the current LLDP-MED voice network policy issue. LLDP-MED extends neighbor discovery with voice-oriented network policy information.
D:Inspect show poe interface and total allocated versus available watts. That check applies chiefly to PoE power budget switch capacity, not the current LLDP-MED voice network policy issue. LLDP-MED extends neighbor discovery with voice-oriented network policy information.
Question 159
A switch has scheduler maps configured yet the intended forwarding class uses the default queue. Which next investigation or correction is MOST appropriate?
- Inspect CoS classification and adjacency stability under data load.
- Review filter counters and packet classification for sample voice and data flows.
- Rename a queue to Priority and assume the physical scheduler configuration changes.
- Inspect class-to-queue association and per-queue statistics.
Explanation
Correct Answer
D:Inspect class-to-queue association and per-queue statistics. This checks whether each packet class reaches the planned output queue with expected counters.
Incorrect Answers
A:Inspect CoS classification and adjacency stability under data load. That check applies chiefly to Network-control forwarding class differentiation, not the current Junos forwarding class to queue mapping issue. Forwarding classes express per-hop traffic treatment and map to transmission queues.
B:Review filter counters and packet classification for sample voice and data flows. That check applies chiefly to Junos multifield firewall filter classification, not the current Junos forwarding class to queue mapping issue. Forwarding classes express per-hop traffic treatment and map to transmission queues.
C:Rename a queue to Priority and assume the physical scheduler configuration changes. That bypass leaves the Junos forwarding class to queue mapping issue unresolved. Naming a class Voice without mapping it does not guarantee queue scheduling.
Question 160
A fabric expects active-active service but one leaf never forwards eligible traffic. Which technical principle BEST explains the EVPN all-active multihoming forwarding decision?
- BGP path eligibility depends on successful next-hop resolution in the routing table.
- EVPN IP/MAC learning can support distributed ARP suppression where platforms support it.
- Type3 IMET routes signal participation in an EVPN broadcast domain for BUM distribution.
- EVPN all-active multihoming can use parallel forwarding paths with designated loop protection.
Explanation
Correct Answer
D:EVPN all-active multihoming can use parallel forwarding paths with designated loop protection. In this situation, the relevant action is to configure supported all-active multihoming mode and compatible LAG or ESI settings.
Incorrect Answers
A:BGP path eligibility depends on successful next-hop resolution in the routing table. That principle is related to BGP next-hop reachability hidden route, not the main EVPN all-active multihoming forwarding choice. Treating both uplinks as independent uncoordinated bridges can form duplication or loops.
B:EVPN IP/MAC learning can support distributed ARP suppression where platforms support it. That principle is related to EVPN ARP suppression from IP MAC bindings, not the main EVPN all-active multihoming forwarding choice. Treating both uplinks as independent uncoordinated bridges can form duplication or loops.
C:Type3 IMET routes signal participation in an EVPN broadcast domain for BUM distribution. That principle is related to EVPN Type3 IMET inclusive multicast routes, not the main EVPN all-active multihoming forwarding choice. Treating both uplinks as independent uncoordinated bridges can form duplication or loops.
