Juniper JN0-650 Practice Test 48
Question 470
A queue policy assigns all routing protocol packets to best effort and sessions flap. Which technical principle BEST explains the Network-control forwarding class differentiation decision?
- Strict priority can reduce latency but must be designed to avoid starvation.
- Network-control traffic may need separate protection from bulk and voice services.
- MSDP can exchange source-active awareness across ASM RP domains.
- Egress buffers absorb short bursts but cannot compensate for persistent overload.
Explanation
Correct Answer
B:Network-control traffic may need separate protection from bulk and voice services. In this situation, the relevant action is to classify authorized control-plane traffic into an appropriate protected forwarding class.
Incorrect Answers
A:Strict priority can reduce latency but must be designed to avoid starvation. That principle is related to Scheduler strict priority and starvation, not the main Network-control forwarding class differentiation choice. Starving critical control-plane messages can trigger cascading route instability.
C:MSDP can exchange source-active awareness across ASM RP domains. That principle is related to MSDP source active exchange, not the main Network-control forwarding class differentiation choice. Starving critical control-plane messages can trigger cascading route instability.
D:Egress buffers absorb short bursts but cannot compensate for persistent overload. That principle is related to Queue buffer-size allocation, not the main Network-control forwarding class differentiation choice. Starving critical control-plane messages can trigger cascading route instability.
Question 471
During an operational risk review, this situation is reported: One authorized device accidentally permits all other downstream MAC addresses. If the underlying control is neglected, which failure would MOST directly follow?
- Missing tagged membership creates silent Layer 2 reachability gaps.
- Treating RADIUS as an EAPOL packet directly emitted by the laptop prevents correct troubleshooting.
- Placing critical admin endpoints behind MAC-only authentication permits spoofing risk.
- Treating one successful login as authorization for every attached client increases exposure.
Explanation
Correct Answer
D:Treating one successful login as authorization for every attached client increases exposure. 802.1X host-mode behavior controls whether access applies per endpoint or per port. A useful corrective investigation is to test authorized and unauthorized MACs behind the same physical port.
Incorrect Answers
A:Missing tagged membership creates silent Layer 2 reachability gaps. This is a 802.1Q trunk allowed VLANs failure pattern, not the primary 802.1X multi-supplicant port control failure in this case. 802.1X host-mode behavior controls whether access applies per endpoint or per port.
B:Treating RADIUS as an EAPOL packet directly emitted by the laptop prevents correct troubleshooting. This is a 802.1X supplicant authenticator RADIUS roles failure pattern, not the primary 802.1X multi-supplicant port control failure in this case. 802.1X host-mode behavior controls whether access applies per endpoint or per port.
C:Placing critical admin endpoints behind MAC-only authentication permits spoofing risk. This is a MAC RADIUS spoofing limitations failure pattern, not the primary 802.1X multi-supplicant port control failure in this case. 802.1X host-mode behavior controls whether access applies per endpoint or per port.
Question 472
An enterprise wants RP group mappings distributed rather than manually repeated. After deploying the recommended PIM RP discovery and bootstrap mapping change, which result MOST directly verifies success?
- Incoming multicast packets arrive on the interface selected by a valid source route.
- A consistent state chain from source to receivers explains successful data delivery.
- The stub receives an appropriate default or interarea reachability without external type-5 flooding.
- Candidate routers acquire the intended RP mappings for authorized multicast ranges.
Explanation
Correct Answer
D:Candidate routers acquire the intended RP mappings for authorized multicast ranges. This is the directly observable outcome for PIM RP discovery and bootstrap mapping. Dynamic RP discovery advertises RP group associations while PIM still requires routing reachability.
Incorrect Answers
A:Incoming multicast packets arrive on the interface selected by a valid source route. This validates Multicast source route policy and RPF but does not directly demonstrate the required PIM RP discovery and bootstrap mapping result. Dynamic RP discovery advertises RP group associations while PIM still requires routing reachability.
B:A consistent state chain from source to receivers explains successful data delivery. This validates Multicast troubleshooting separate control and data planes but does not directly demonstrate the required PIM RP discovery and bootstrap mapping result. Dynamic RP discovery advertises RP group associations while PIM still requires routing reachability.
C:The stub receives an appropriate default or interarea reachability without external type-5 flooding. This validates OSPF stub area external LSA suppression but does not directly demonstrate the required PIM RP discovery and bootstrap mapping result. Dynamic RP discovery advertises RP group associations while PIM still requires routing reachability.
Question 473
During an operational risk review, this situation is reported: A customer edge inserts stacked tags that an intermediate switch drops as malformed. If the underlying control is neglected, which failure would MOST directly follow?
- Troubleshooting only end-host IP routes can miss a transport VLAN mismatch.
- Mis-scoped multicast can leak too far or fail to reach authorized hosts.
- Mismatched TPID assumptions can cause customer frames to be dropped.
- Different BPDU handling per VLAN can leave only some VLANs unprotected.
Explanation
Correct Answer
C:Mismatched TPID assumptions can cause customer frames to be dropped. VLAN stacking requires compatible tag interpretation and consistent port behavior. A useful corrective investigation is to decode Ethernet EtherType and both VLAN IDs in packet captures.
Incorrect Answers
A:VLAN stacking requires compatible tag interpretation and consistent port behavior. Troubleshooting only end-host IP routes can miss a transport VLAN mismatch.
B:VLAN stacking requires compatible tag interpretation and consistent port behavior. Mis-scoped multicast can leak too far or fail to reach authorized hosts.
D:VLAN stacking requires compatible tag interpretation and consistent port behavior. Different BPDU handling per VLAN can leave only some VLANs unprotected.
Question 474
Routers connected over a multicast transit VLAN do not discover PIM neighbors. Which configuration or operational step BEST meets the stated requirement?
- Configure supported MSDP peering and source-active advertisements between intended RP nodes.
- Configure only LLDP neighbors and assume PIM joins are exchanged.
- Enable compatible PIM on intended routed interfaces and verify neighbor discovery.
- Configure supported dynamic RP discovery or bootstrap policies where the topology supports them.
Explanation
Correct Answer
C:Enable compatible PIM on intended routed interfaces and verify neighbor discovery. PIM establishes multicast router adjacencies independently of host IGMP group membership. The expected validation is that both routers see expected PIM neighbors and build join state.
Incorrect Answers
A:Configure supported MSDP peering and source-active advertisements between intended RP nodes. This addresses MSDP source active exchange rather than the required PIM sparse-mode neighbor discovery decision. PIM establishes multicast router adjacencies independently of host IGMP group membership.
B:Configure only LLDP neighbors and assume PIM joins are exchanged. This is a risky or ineffective shortcut for PIM sparse-mode neighbor discovery. IGMP-only interfaces do not create interrouter PIM forwarding state.
D:Configure supported dynamic RP discovery or bootstrap policies where the topology supports them. This addresses PIM RP discovery and bootstrap mapping rather than the required PIM sparse-mode neighbor discovery decision. PIM establishes multicast router adjacencies independently of host IGMP group membership.
Question 475
A branch adjacency flaps after one interface uses a much shorter dead timer. Select TWO statements that correctly combine the OSPFv2 Hello and Dead timer adjacency implementation, its evidence, or its governing principle.
- Change only the router ID and claim incompatible timer settings will be ignored.
- Compare Hello packets area ID intervals and neighbor states before changing interface OSPF settings.
- Apply a guarded OSPFv3 export policy matching the correct inet6 source and prefix.
- Put both interfaces in the same intended OSPF area and verify shared area policy.
- A full adjacency forms after bidirectional Hellos and compatible timers are observed.
Explanation
Correct Answers
B:Compare Hello packets area ID intervals and neighbor states before changing interface OSPF settings. This is the intended implementation action for OSPFv2 Hello and Dead timer adjacency.
E:A full adjacency forms after bidirectional Hellos and compatible timers are observed. This is direct observable evidence for OSPFv2 Hello and Dead timer adjacency.
Incorrect Answers
A:Change only the router ID and claim incompatible timer settings will be ignored. This would not be an appropriate OSPFv2 Hello and Dead timer adjacency decision. Mismatched Hello or Dead intervals block a reliable adjacency.
C:Apply a guarded OSPFv3 export policy matching the correct inet6 source and prefix. This belongs to OSPFv3 routing policy for external IPv6, not the specified OSPFv2 Hello and Dead timer adjacency operation. OSPF neighbors exchange compatible Hellos before database synchronization.
D:Put both interfaces in the same intended OSPF area and verify shared area policy. This belongs to OSPFv2 area identifier consistency, not the specified OSPFv2 Hello and Dead timer adjacency operation. OSPF neighbors exchange compatible Hellos before database synchronization.
Question 476
Network design requires stronger authorization for privileged endpoints than a known hardware address. Which technical principle BEST explains the MAC RADIUS spoofing limitations decision?
- Authentication monitoring must inspect credentials authorization and port state separately.
- Filter-based VLAN decisions can classify traffic by supported packet fields instead of fixed port membership alone.
- Guest VLAN authorizes limited access for eligible unauthenticated clients.
- MAC addresses can be imitated and are weaker credentials than authenticated EAP identities.
Explanation
Correct Answer
D:MAC addresses can be imitated and are weaker credentials than authenticated EAP identities. In this situation, the relevant action is to restrict MAC RADIUS to low-trust device segments and use stronger 802.1X for capable users.
Incorrect Answers
A:Authentication monitoring must inspect credentials authorization and port state separately. That principle is related to Junos Layer 2 authentication session monitoring, not the main MAC RADIUS spoofing limitations choice. Placing critical admin endpoints behind MAC-only authentication permits spoofing risk.
B:Filter-based VLAN decisions can classify traffic by supported packet fields instead of fixed port membership alone. That principle is related to Filter-based VLAN assignment, not the main MAC RADIUS spoofing limitations choice. Placing critical admin endpoints behind MAC-only authentication permits spoofing risk.
C:Guest VLAN authorizes limited access for eligible unauthenticated clients. That principle is related to Guest VLAN for unauthenticated clients, not the main MAC RADIUS spoofing limitations choice. Placing critical admin endpoints behind MAC-only authentication permits spoofing risk.
Question 477
A network upgrade leaves old reference bandwidth values across Junos routing domains. Which technical principle BEST explains the OSPF reference bandwidth and high-speed links decision?
- EVPN route targets control distribution membership independently of VNI packet encapsulation.
- OSPF automatic cost can require reference-bandwidth adjustment as interfaces become faster.
- OSPF SPF selects lowest cumulative link cost subject to policy and availability.
- Two-Way may be normal between DROther neighbors while Exchange stuck indicates database issues.
Explanation
Correct Answer
B:OSPF automatic cost can require reference-bandwidth adjustment as interfaces become faster. In this situation, the relevant action is to use a consistent OSPF reference-bandwidth policy across the intended routing domain.
Incorrect Answers
A:EVPN route targets control distribution membership independently of VNI packet encapsulation. That principle is related to EVPN route target import export scope, not the main OSPF reference bandwidth and high-speed links choice. Inconsistent reference bandwidth across routers may distort intended route decisions.
C:OSPF SPF selects lowest cumulative link cost subject to policy and availability. That principle is related to OSPF path cost selection, not the main OSPF reference bandwidth and high-speed links choice. Inconsistent reference bandwidth across routers may distort intended route decisions.
D:Two-Way may be normal between DROther neighbors while Exchange stuck indicates database issues. That principle is related to OSPF neighbor state troubleshooting workflow, not the main OSPF reference bandwidth and high-speed links choice. Inconsistent reference bandwidth across routers may distort intended route decisions.
Question 478
A new link cost changes which MSTI uplink forwards unexpectedly. Select TWO statements that correctly combine the MSTP root port and alternate path implementation, its evidence, or its governing principle.
- Configure appropriate VSTP VLAN-specific bridge priorities and port values.
- Create controlled firewall-filter-based VLAN classification on eligible ingress interfaces.
- Disable BPDU handling to make all redundant uplinks forward without loop risk.
- Tune approved MST port costs and priorities based on the intended topology.
- Root and alternate ports correspond to the planned loop-free spanning tree.
Explanation
Correct Answers
D:Tune approved MST port costs and priorities based on the intended topology. This is the intended implementation action for MSTP root port and alternate path.
E:Root and alternate ports correspond to the planned loop-free spanning tree. This is direct observable evidence for MSTP root port and alternate path.
Incorrect Answers
A:Configure appropriate VSTP VLAN-specific bridge priorities and port values. This belongs to VSTP per-VLAN root distribution, not the specified MSTP root port and alternate path operation. Spanning tree chooses port roles to avoid loops while maintaining redundant paths.
B:Create controlled firewall-filter-based VLAN classification on eligible ingress interfaces. This belongs to Filter-based VLAN assignment, not the specified MSTP root port and alternate path operation. Spanning tree chooses port roles to avoid loops while maintaining redundant paths.
C:Disable BPDU handling to make all redundant uplinks forward without loop risk. This would not be an appropriate MSTP root port and alternate path decision. Forcing every redundant port to forwarding can create broadcast storms.
Question 479
Two leaf switches connect to one dual-homed server using an ESI-LAG. Which configuration or operational step BEST meets the stated requirement?
- Enable compatible BGP EVPN signaling on the appropriate peers with scoped policy.
- Set the same OSPF router ID and assume it creates a shared EVPN Ethernet segment.
- Configure supported all-active multihoming mode and compatible LAG or ESI settings.
- Configure matching supported Ethernet segment identifier and multihoming attachments.
Explanation
Correct Answer
D:Configure matching supported Ethernet segment identifier and multihoming attachments. ESI identifies a shared multihomed Ethernet segment to EVPN control plane. The expected validation is that peers agree on a common Ethernet segment and relevant EVPN ES routes.
Incorrect Answers
A:Enable compatible BGP EVPN signaling on the appropriate peers with scoped policy. This addresses BGP EVPN address-family peer negotiation rather than the required Ethernet segment identifier ESI consistency decision. ESI identifies a shared multihomed Ethernet segment to EVPN control plane.
B:Set the same OSPF router ID and assume it creates a shared EVPN Ethernet segment. This is a risky or ineffective shortcut for Ethernet segment identifier ESI consistency. Different ESI values on supposed peers can defeat multihoming loop protection.
C:Configure supported all-active multihoming mode and compatible LAG or ESI settings. This addresses EVPN all-active multihoming forwarding rather than the required Ethernet segment identifier ESI consistency decision. ESI identifies a shared multihomed Ethernet segment to EVPN control plane.
Question 480
An engineer expects a rewrite rule to change a packet's ingress forwarding class. Which configuration or operational step BEST meets the stated requirement?
- Trace classifier forwarding class PLP scheduler and rewrite stages in the correct pipeline order.
- Configure supported IEEE 802.1p rewrite mapping at the Ethernet egress boundary.
- Apply the intended scheduler map to the actual output interface.
- Configure one routing policy term and assume all CoS stages are automatically active.
Explanation
Correct Answer
A:Trace classifier forwarding class PLP scheduler and rewrite stages in the correct pipeline order. Junos CoS decisions progress from ingress classification through queue scheduling to egress rewriting. The expected validation is that captures and counters explain ingress class egress queue and final header marking.
Incorrect Answers
B:Configure supported IEEE 802.1p rewrite mapping at the Ethernet egress boundary. This addresses IEEE 802.1p CoS rewrite on Ethernet rather than the required CoS processing order ingress to egress decision. Junos CoS decisions progress from ingress classification through queue scheduling to egress rewriting.
C:Apply the intended scheduler map to the actual output interface. This addresses Scheduler maps attached to egress interface rather than the required CoS processing order ingress to egress decision. Junos CoS decisions progress from ingress classification through queue scheduling to egress rewriting.
D:Configure one routing policy term and assume all CoS stages are automatically active. This is a risky or ineffective shortcut for CoS processing order ingress to egress. Configuring only an egress rewrite does not automatically set an upstream classifier.
