Juniper JN0-650 Practice Test 9
Question 80
A multiarea OSPF topology has a nonbackbone area disconnected from area zero. Which configuration or operational step BEST meets the stated requirement?
- Create a separate nonbackbone area ID at both ends and expect it to substitute for area zero.
- Configure compatible stub area attributes on all affected OSPF routers.
- Compare Hello packets area ID intervals and neighbor states before changing interface OSPF settings.
- Restore valid area 0 backbone connectivity and supported ABR relationships.
Explanation
Correct Answer
D:Restore valid area 0 backbone connectivity and supported ABR relationships. Standard multi-area OSPF uses the backbone to exchange interarea information. The expected validation is that interarea prefixes traverse the intended backbone with stable SPF reachability.
Incorrect Answers
A:Create a separate nonbackbone area ID at both ends and expect it to substitute for area zero. This is a risky or ineffective shortcut for OSPF area-border backbone connectivity. Designing arbitrary direct interarea exchanges without a backbone can partition routing.
B:Configure compatible stub area attributes on all affected OSPF routers. This addresses OSPF stub area external LSA suppression rather than the required OSPF area-border backbone connectivity decision. Standard multi-area OSPF uses the backbone to exchange interarea information.
C:Compare Hello packets area ID intervals and neighbor states before changing interface OSPF settings. This addresses OSPFv2 Hello and Dead timer adjacency rather than the required OSPF area-border backbone connectivity decision. Standard multi-area OSPF uses the backbone to exchange interarea information.
Question 81
Two routers can ping each other but TCP port 179 is filtered in one direction. After deploying the recommended BGP TCP 179 and firewall reachability change, which result MOST directly verifies success?
- Outgoing routes retain required communities without leaking internal-only tag values.
- Peering establishes over the authorized endpoints without opening unrelated management ports.
- Approved voice packets gain the intended forwarding class while bulk packets do not.
- Tagged prefixes follow documented export or preference behavior at the target neighbor.
Explanation
Correct Answer
B:Peering establishes over the authorized endpoints without opening unrelated management ports. This is the directly observable outcome for BGP TCP 179 and firewall reachability. BGP relies on TCP transport and does not form merely because IP reachability exists.
Incorrect Answers
A:Outgoing routes retain required communities without leaking internal-only tag values. This validates BGP communities match and deletion but does not directly demonstrate the required BGP TCP 179 and firewall reachability result. BGP relies on TCP transport and does not form merely because IP reachability exists.
C:Approved voice packets gain the intended forwarding class while bulk packets do not. This validates Junos multifield firewall filter classification but does not directly demonstrate the required BGP TCP 179 and firewall reachability result. BGP relies on TCP transport and does not form merely because IP reachability exists.
D:Tagged prefixes follow documented export or preference behavior at the target neighbor. This validates BGP communities tagging routing intent but does not directly demonstrate the required BGP TCP 179 and firewall reachability result. BGP relies on TCP transport and does not form merely because IP reachability exists.
Question 82
Higher-power phones boot only when fewer neighboring ports are active. Which next investigation or correction is MOST appropriate?
- Change the voice VLAN IP address and assume it increases available PoE wattage.
- Inspect show poe interface and total allocated versus available watts.
- Inspect LLDP-MED advertisements and tagged phone frames on the link.
- Inspect LLDP-MED network policy fields and captured 802.1Q priority bits.
Explanation
Correct Answer
B:Inspect show poe interface and total allocated versus available watts. This checks whether all approved phones receive adequate negotiated power without exceeding switch capacity.
Incorrect Answers
A:Change the voice VLAN IP address and assume it increases available PoE wattage. That bypass leaves the PoE power budget switch capacity issue unresolved. Summing device requirements above available chassis budget causes port power denial.
C:Inspect LLDP-MED advertisements and tagged phone frames on the link. That check applies chiefly to LLDP-MED voice network policy, not the current PoE power budget switch capacity issue. IEEE PoE total power budget and per-port allocation constrain powered endpoints.
D:Inspect LLDP-MED network policy fields and captured 802.1Q priority bits. That check applies chiefly to LLDP-MED voice priority signaling, not the current PoE power budget switch capacity issue. IEEE PoE total power budget and per-port allocation constrain powered endpoints.
Question 83
A tenant's unicast works but unknown unicast and broadcast frames never reach remote leaves. Which configuration or operational step BEST meets the stated requirement?
- Validate EVPN Type3 inclusive multicast route advertisement and remote replication lists.
- Replace every Type3 route with a BGP unicast default and assume BUM replication is preserved.
- Enable compatible BGP EVPN signaling on the appropriate peers with scoped policy.
- Advertise correct EVPN Type1 Ethernet auto-discovery routes for the segment.
Explanation
Correct Answer
A:Validate EVPN Type3 inclusive multicast route advertisement and remote replication lists. Type3 IMET routes signal participation in an EVPN broadcast domain for BUM distribution. The expected validation is that each participating VTEP has the required BUM flood destinations for the VNI.
Incorrect Answers
B:Replace every Type3 route with a BGP unicast default and assume BUM replication is preserved. This is a risky or ineffective shortcut for EVPN Type3 IMET inclusive multicast routes. Missing IMET state can break ARP and unknown unicast even with selected Type2 routes.
C:Enable compatible BGP EVPN signaling on the appropriate peers with scoped policy. This addresses BGP EVPN address-family peer negotiation rather than the required EVPN Type3 IMET inclusive multicast routes decision. Type3 IMET routes signal participation in an EVPN broadcast domain for BUM distribution.
D:Advertise correct EVPN Type1 Ethernet auto-discovery routes for the segment. This addresses EVPN Type1 Ethernet auto discovery rather than the required EVPN Type3 IMET inclusive multicast routes decision. Type3 IMET routes signal participation in an EVPN broadcast domain for BUM distribution.
Question 84
A branch adjacency flaps after one interface uses a much shorter dead timer. Which technical principle BEST explains the OSPFv2 Hello and Dead timer adjacency decision?
- OSPF neighbors exchange compatible Hellos before database synchronization.
- OSPF SPF selects lowest cumulative link cost subject to policy and availability.
- Multiple authentication methods must be composed without creating a bypass path.
- OSPF authentication compatibility is independent of ordinary IP reachability.
Explanation
Correct Answer
A:OSPF neighbors exchange compatible Hellos before database synchronization. In this situation, the relevant action is to compare Hello packets area ID intervals and neighbor states before changing interface OSPF settings.
Incorrect Answers
B:OSPF SPF selects lowest cumulative link cost subject to policy and availability. That principle is related to OSPF path cost selection, not the main OSPFv2 Hello and Dead timer adjacency choice. Mismatched Hello or Dead intervals block a reliable adjacency.
C:Multiple authentication methods must be composed without creating a bypass path. That principle is related to 802.1X versus MAC RADIUS method priority, not the main OSPFv2 Hello and Dead timer adjacency choice. Mismatched Hello or Dead intervals block a reliable adjacency.
D:OSPF authentication compatibility is independent of ordinary IP reachability. That principle is related to OSPF authentication key or algorithm, not the main OSPFv2 Hello and Dead timer adjacency choice. Mismatched Hello or Dead intervals block a reliable adjacency.
Question 85
A queue policy assigns all routing protocol packets to best effort and sessions flap. Which next investigation or correction is MOST appropriate?
- Decode outbound VLAN tag priority versus Layer 3 DSCP in packet capture.
- Use a user browser's HTTP cookies as the Junos routing-protocol control class.
- Inspect CoS classification and adjacency stability under data load.
- Measure queue throughput and share under controlled competing traffic.
Explanation
Correct Answer
C:Inspect CoS classification and adjacency stability under data load. This checks whether routing control packets show stable service during expected congestion.
Incorrect Answers
A:Decode outbound VLAN tag priority versus Layer 3 DSCP in packet capture. That check applies chiefly to IEEE 802.1p CoS rewrite on Ethernet, not the current Network-control forwarding class differentiation issue. Network-control traffic may need separate protection from bulk and voice services.
B:Use a user browser's HTTP cookies as the Junos routing-protocol control class. That bypass leaves the Network-control forwarding class differentiation issue unresolved. Starving critical control-plane messages can trigger cascading route instability.
D:Measure queue throughput and share under controlled competing traffic. That check applies chiefly to Scheduler transmit rate bandwidth allocation, not the current Network-control forwarding class differentiation issue. Network-control traffic may need separate protection from bulk and voice services.
Question 86
A shaper is mistakenly treated as an ingress drop-based policer. Which next investigation or correction is MOST appropriate?
- Measure queue throughput and share under controlled competing traffic.
- Measure egress rate and queue delay during sustained load.
- Review filter counters and packet classification for sample voice and data flows.
- Apply a policer to random ingress VLANs and assume it is equivalent to egress shaping.
Explanation
Correct Answer
B:Measure egress rate and queue delay during sustained load. This checks whether aggregate traffic conforms to the carrier contract without unnecessary downstream discards.
Incorrect Answers
A:Measure queue throughput and share under controlled competing traffic. That check applies chiefly to Scheduler transmit rate bandwidth allocation, not the current Junos egress shaping rate issue. Shaping delays packets to smooth egress rate while policing meters and may drop.
C: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 egress shaping rate issue. Shaping delays packets to smooth egress rate while policing meters and may drop.
D:Apply a policer to random ingress VLANs and assume it is equivalent to egress shaping. That bypass leaves the Junos egress shaping rate issue unresolved. Shaping above a carrier limit can shift congestion to an uncontrolled downstream point.
Question 87
During an operational risk review, this situation is reported: A routed Ethernet cross-connect has only two OSPF neighbors but shows a DR and BDR. If the underlying control is neglected, which failure would MOST directly follow?
- Mixed OSPF interface network types can produce confusing neighbor behavior.
- Inconsistent reference bandwidth across routers may distort intended route decisions.
- Mixing stub and normal-area settings prevents correct neighbor establishment.
- Predicting equal utilization for a single heavy flow misunderstands per-flow selection.
Explanation
Correct Answer
A:Mixed OSPF interface network types can produce confusing neighbor behavior. Point-to-point OSPF interfaces do not use broadcast-network DR election. A useful corrective investigation is to verify per-interface network type and Hello processing at both endpoints.
Incorrect Answers
B:Point-to-point OSPF interfaces do not use broadcast-network DR election. This is a OSPF reference bandwidth and high-speed links failure pattern, not the primary OSPF point-to-point network type failure in this case.
C:Point-to-point OSPF interfaces do not use broadcast-network DR election. Mixing stub and normal-area settings prevents correct neighbor establishment.
D:Point-to-point OSPF interfaces do not use broadcast-network DR election. This is a BGP ECMP per-flow hashing failure pattern, not the primary OSPF point-to-point network type failure in this case.
Question 88
During an operational risk review, this situation is reported: An engineer changes a transit interface cost but routes still choose an unexpected next hop. If the underlying control is neglected, which failure would MOST directly follow?
- Assuming every high-priority router instantly replaces the current DR leads to wrong operational expectations.
- Overlooking total cost can route critical traffic over a constrained backup path.
- Merely seeing multiple BGP routes does not prove load balancing occurs.
- Mistaking local import rejection for universal LSA suppression produces false reachability assumptions.
Explanation
Correct Answer
B:Overlooking total cost can route critical traffic over a constrained backup path. OSPF SPF selects lowest cumulative link cost subject to policy and availability. A useful corrective investigation is to compare show route protocol ospf and interface metric contributions along both paths.
Incorrect Answers
A:Assuming every high-priority router instantly replaces the current DR leads to wrong operational expectations. This is a OSPF designated router election broadcast LAN failure pattern, not the primary OSPF path cost selection failure in this case. OSPF SPF selects lowest cumulative link cost subject to policy and availability.
C:Merely seeing multiple BGP routes does not prove load balancing occurs. This is a BGP multipath equal-cost path installation failure pattern, not the primary OSPF path cost selection failure in this case. OSPF SPF selects lowest cumulative link cost subject to policy and availability.
D:Mistaking local import rejection for universal LSA suppression produces false reachability assumptions. This is a OSPF routing policy import filtering failure pattern, not the primary OSPF path cost selection failure in this case. OSPF SPF selects lowest cumulative link cost subject to policy and availability.
Question 89
A conference-room port connects several users through a small downstream switch. After deploying the recommended 802.1X multi-supplicant port control change, which result MOST directly verifies success?
- Each permitted identity is authorized without inheriting unrelated devices' access.
- Authenticated users enter the intended authorized VLAN while rejected users do not.
- Egress queue behavior follows the scheduler-map settings during representative load.
- Session logs identify the failing exchange or authorized role without broad policy bypass.
Explanation
Correct Answer
A:Each permitted identity is authorized without inheriting unrelated devices' access. This is the directly observable outcome for 802.1X multi-supplicant port control. 802.1X host-mode behavior controls whether access applies per endpoint or per port.
Incorrect Answers
B:Authenticated users enter the intended authorized VLAN while rejected users do not. This validates Dynamic VLAN assignment from RADIUS but does not directly demonstrate the required 802.1X multi-supplicant port control result. 802.1X host-mode behavior controls whether access applies per endpoint or per port.
C:Egress queue behavior follows the scheduler-map settings during representative load. This validates Scheduler maps attached to egress interface but does not directly demonstrate the required 802.1X multi-supplicant port control result. 802.1X host-mode behavior controls whether access applies per endpoint or per port.
D:Session logs identify the failing exchange or authorized role without broad policy bypass. This validates Junos Layer 2 authentication session monitoring but does not directly demonstrate the required 802.1X multi-supplicant port control result. 802.1X host-mode behavior controls whether access applies per endpoint or per port.
Question 90
One customer VLAN is mapped to the wrong VNI on a leaf. Which configuration or operational step BEST meets the stated requirement?
- Set compatible route-target import and export policy for intended EVPN instances.
- Configure consistent supported VLAN-to-VNI mapping in the intended routing instances.
- Verify local MAC learning and Type2 MAC/IP route advertisement and import.
- Rename tenant VLANs to identical names and assume the VNI collision becomes safe.
Explanation
Correct Answer
B:Configure consistent supported VLAN-to-VNI mapping in the intended routing instances. VXLAN network identifiers distinguish overlay Layer 2 broadcast domains. The expected validation is that same-segment endpoints communicate while other VNIs remain isolated.
Incorrect Answers
A:Set compatible route-target import and export policy for intended EVPN instances. This addresses EVPN route target import export scope rather than the required VXLAN VNI to VLAN association decision. VXLAN network identifiers distinguish overlay Layer 2 broadcast domains.
C:Verify local MAC learning and Type2 MAC/IP route advertisement and import. This addresses EVPN Type2 MAC IP advertisement rather than the required VXLAN VNI to VLAN association decision. VXLAN network identifiers distinguish overlay Layer 2 broadcast domains.
D:Rename tenant VLANs to identical names and assume the VNI collision becomes safe. This is a risky or ineffective shortcut for VXLAN VNI to VLAN association. Reusing wrong VNI mapping can leak traffic across tenant boundaries or break reachability.