Juniper JN0-650 Practice Test 13
Question 120
Schedulers are defined in configuration but no QoS behavior is observed on a busy uplink. After deploying the recommended Scheduler maps attached to egress interface change, which result MOST directly verifies success?
- Packet counters show EF-marked traffic assigned to approved forwarding class and queue.
- Captures and counters explain ingress class egress queue and final header marking.
- BGP reaches Established with the expected local and remote ASN and prefix families.
- Egress queue behavior follows the scheduler-map settings during representative load.
Explanation
Correct Answer
D:Egress queue behavior follows the scheduler-map settings during representative load. This is the directly observable outcome for Scheduler maps attached to egress interface. Scheduler maps associate forwarding classes with schedulers and require interface application.
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 Scheduler maps attached to egress interface result. Scheduler maps associate forwarding classes with schedulers and require interface application.
B:Captures and counters explain ingress class egress queue and final header marking. This validates CoS processing order ingress to egress but does not directly demonstrate the required Scheduler maps attached to egress interface result. Scheduler maps associate forwarding classes with schedulers and require interface application.
C:BGP reaches Established with the expected local and remote ASN and prefix families. This validates BGP eBGP peer AS and local identity but does not directly demonstrate the required Scheduler maps attached to egress interface result. Scheduler maps associate forwarding classes with schedulers and require interface application.
Question 121
A network team needs to distinguish class-mapping errors from physical link saturation. Select TWO statements that correctly combine the CoS end-to-end verification of drop behavior implementation, its evidence, or its governing principle.
- Configure appropriate rewrite rules mapping forwarding class and PLP to egress DSCP.
- Trace classifier forwarding class PLP scheduler and rewrite stages in the correct pipeline order.
- Under controlled load intended voice QoS remains protected while other classes retain service.
- Combine per-class classification queue occupancy drop and packet-marking evidence across bottlenecks.
- Disable all class-of-service monitoring because one show configuration command succeeded.
Explanation
Correct Answers
C:Under controlled load intended voice QoS remains protected while other classes retain service. This is direct observable evidence for CoS end-to-end verification of drop behavior.
D:Combine per-class classification queue occupancy drop and packet-marking evidence across bottlenecks. This is the intended implementation action for CoS end-to-end verification of drop behavior.
Incorrect Answers
A:Configure appropriate rewrite rules mapping forwarding class and PLP to egress DSCP. This belongs to DSCP egress rewrite rules, not the specified CoS end-to-end verification of drop behavior operation. Successful CoS needs consistent ingress classification egress scheduling and congestion management.
B:Trace classifier forwarding class PLP scheduler and rewrite stages in the correct pipeline order. This belongs to CoS processing order ingress to egress, not the specified CoS end-to-end verification of drop behavior operation. Successful CoS needs consistent ingress classification egress scheduling and congestion management.
E:Disable all class-of-service monitoring because one show configuration command succeeded. This would not be an appropriate CoS end-to-end verification of drop behavior decision. Inspecting only a configured class name can hide actual drops and misclassification.
Question 122
A provider changes its ASN and a previously stable BGP session stops opening. Which technical principle BEST explains the BGP eBGP peer AS and local identity decision?
- BGP OPEN exchange checks autonomous-system identity and capability compatibility.
- 802.1X separates supplicant authenticator and authentication server roles.
- BGP route reflection reduces iBGP full-mesh needs using originator and cluster loop controls.
- Route damping suppresses unstable routes but adds recovery latency.
Explanation
Correct Answer
A:BGP OPEN exchange checks autonomous-system identity and capability compatibility. In this situation, the relevant action is to configure matching local and peer AS settings and verify session transport.
Incorrect Answers
B:802.1X separates supplicant authenticator and authentication server roles. That principle is related to 802.1X supplicant authenticator RADIUS roles, not the main BGP eBGP peer AS and local identity choice. Wrong peer-AS values cause BGP OPEN rejection despite TCP connectivity.
C:BGP route reflection reduces iBGP full-mesh needs using originator and cluster loop controls. That principle is related to BGP route reflection cluster, not the main BGP eBGP peer AS and local identity choice. Wrong peer-AS values cause BGP OPEN rejection despite TCP connectivity.
D:Route damping suppresses unstable routes but adds recovery latency. That principle is related to BGP route damping flap penalty, not the main BGP eBGP peer AS and local identity choice. Wrong peer-AS values cause BGP OPEN rejection despite TCP connectivity.
Question 123
During an operational risk review, this situation is reported: A leaf's loopback address disappears from the fabric underlay after a routing change. If the underlying control is neglected, which failure would MOST directly follow?
- An unexpected source route preference may cause RPF failures after a control-plane change.
- Different ESI values on supposed peers can defeat multihoming loop protection.
- Lack of split-horizon handling can cause duplicate or looping flooded frames.
- An EVPN Type2 route with unreachable tunnel next hop cannot deliver traffic.
Explanation
Correct Answer
D:An EVPN Type2 route with unreachable tunnel next hop cannot deliver traffic. VXLAN data plane depends on routable VTEP endpoints independent of EVPN MAC learning. A useful corrective investigation is to inspect route to VTEP loopback and VXLAN encapsulation transport.
Incorrect Answers
A:An unexpected source route preference may cause RPF failures after a control-plane change. This is a Multicast source route policy and RPF failure pattern, not the primary VXLAN VTEP loopback underlay route failure in this case. VXLAN data plane depends on routable VTEP endpoints independent of EVPN MAC learning.
B:Different ESI values on supposed peers can defeat multihoming loop protection. This is a Ethernet segment identifier ESI consistency failure pattern, not the primary VXLAN VTEP loopback underlay route failure in this case. VXLAN data plane depends on routable VTEP endpoints independent of EVPN MAC learning.
C:Lack of split-horizon handling can cause duplicate or looping flooded frames. This is a EVPN multihoming split horizon loop avoidance failure pattern, not the primary VXLAN VTEP loopback underlay route failure in this case. VXLAN data plane depends on routable VTEP endpoints independent of EVPN MAC learning.
Question 124
During an operational risk review, this situation is reported: A dual-stack interface has an IPv4 DSCP classifier but no equivalent IPv6 treatment. If the underlying control is neglected, which failure would MOST directly follow?
- Assuming an IPv4-only classifier handles all IPv6 traffic may cause inconsistent QoS.
- Shaping above a carrier limit can shift congestion to an uncontrolled downstream point.
- Treating every packet as identical PLP may defeat differentiated congestion policy.
- Reusing an IPv4-only route filter can leave IPv6 export expectations unmet.
Explanation
Correct Answer
A:Assuming an IPv4-only classifier handles all IPv6 traffic may cause inconsistent QoS. Packet classification must account for the correct protocol header family. A useful corrective investigation is to inspect classifier family and IPv6 marked packet queue counters.
Incorrect Answers
B:Packet classification must account for the correct protocol header family. Shaping above a carrier limit can shift congestion to an uncontrolled downstream point.
C:Packet classification must account for the correct protocol header family. This is a Packet loss priority PLP marking failure pattern, not the primary Junos IPv6 DSCP classifier family failure in this case.
D:Packet classification must account for the correct protocol header family. Reusing an IPv4-only route filter can leave IPv6 export expectations unmet.
Question 125
A legacy IGMPv2 receiver cannot express a desired source-specific include list. Which next investigation or correction is MOST appropriate?
- Inspect IGMPv3 (S,G) membership report and associated forwarding state.
- Configure an 802.1Q VLAN name that contains the source address and call it IGMPv3 filtering.
- Verify denied-group counters and successful forwarding for approved test groups.
- Trace multicast forwarding entries hop by hop toward source or RP.
Explanation
Correct Answer
A:Inspect IGMPv3 (S,G) membership report and associated forwarding state. This checks whether the IGMP state records the intended source and excludes other senders.
Incorrect Answers
B:Configure an 802.1Q VLAN name that contains the source address and call it IGMPv3 filtering. That bypass leaves the IGMPv3 source include mode issue unresolved. Using group-only membership can accept unwanted sources in a source-specific design.
C:Verify denied-group counters and successful forwarding for approved test groups. That check applies chiefly to Multicast policy group scoping, not the current IGMPv3 source include mode issue. IGMPv3 supports source filters needed for Source Specific Multicast participation.
D:Trace multicast forwarding entries hop by hop toward source or RP. That check applies chiefly to PIM join prune forwarding path, not the current IGMPv3 source include mode issue. IGMPv3 supports source filters needed for Source Specific Multicast participation.
Question 126
Customer routes need a tag indicating backup-only export handling. Which configuration or operational step BEST meets the stated requirement?
- Rename a BGP group Backup and assume it inserts communities into all updates.
- Add approved BGP community tags and match them in explicit import or export policies.
- Implement ordered Junos policy terms with prefix match and explicit accept or reject decisions.
- Trace BGP received route status through import policy next-hop resolution and path eligibility.
Explanation
Correct Answer
B:Add approved BGP community tags and match them in explicit import or export policies. BGP communities carry policy metadata without directly supplying next-hop reachability. The expected validation is that tagged prefixes follow documented export or preference behavior at the target neighbor.
Incorrect Answers
A:Rename a BGP group Backup and assume it inserts communities into all updates. This is a risky or ineffective shortcut for BGP communities tagging routing intent. Marking a community without a matching policy may not change routing.
C:Implement ordered Junos policy terms with prefix match and explicit accept or reject decisions. This addresses Junos BGP policy term matching rather than the required BGP communities tagging routing intent decision. BGP communities carry policy metadata without directly supplying next-hop reachability.
D:Trace BGP received route status through import policy next-hop resolution and path eligibility. This addresses BGP hidden and rejected path diagnosis rather than the required BGP communities tagging routing intent decision. BGP communities carry policy metadata without directly supplying next-hop reachability.
Question 127
Different Junos routers use conflicting RP addresses for the same ASM range. Which configuration or operational step BEST meets the stated requirement?
- Verify PIM join prune messages and incoming outgoing interface lists across the chain.
- Apply a consistent scoped RP mapping with verified routing to the RP.
- Set a BGP community called RP and assume all PIM routers adopt it.
- Configure reachable appropriate RP mapping for the required ASM group range.
Explanation
Correct Answer
B:Apply a consistent scoped RP mapping with verified routing to the RP. RP mapping and unicast RP reachability are separate multicast requirements. The expected validation is that every receiver-facing router resolves the same intended RP for each permitted group.
Incorrect Answers
A:Verify PIM join prune messages and incoming outgoing interface lists across the chain. This addresses PIM join prune forwarding path rather than the required Static RP mapping group range decision. RP mapping and unicast RP reachability are separate multicast requirements.
C:Set a BGP community called RP and assume all PIM routers adopt it. This is a risky or ineffective shortcut for Static RP mapping group range. Inconsistent RP views can divide a single group into separate multicast trees.
D:Configure reachable appropriate RP mapping for the required ASM group range. This addresses PIM sparse-mode RP shared tree rather than the required Static RP mapping group range decision. RP mapping and unicast RP reachability are separate multicast requirements.
Question 128
Customer routes need a tag indicating backup-only export handling. After deploying the recommended BGP communities tagging routing intent change, which result MOST directly verifies success?
- Multiple eligible next hops are installed and traffic follows approved ECMP hashing.
- Eligible VLAN registration propagates and the intended traffic crosses participating trunks.
- Received and advertised route sets satisfy their separate intended controls.
- Tagged prefixes follow documented export or preference behavior at the target neighbor.
Explanation
Correct Answer
D:Tagged prefixes follow documented export or preference behavior at the target neighbor. This is the directly observable outcome for BGP communities tagging routing intent. BGP communities carry policy metadata without directly supplying next-hop reachability.
Incorrect Answers
A:Multiple eligible next hops are installed and traffic follows approved ECMP hashing. This validates BGP multipath equal-cost path installation but does not directly demonstrate the required BGP communities tagging routing intent result. BGP communities carry policy metadata without directly supplying next-hop reachability.
B:Eligible VLAN registration propagates and the intended traffic crosses participating trunks. This validates MVRP dynamic VLAN registration but does not directly demonstrate the required BGP communities tagging routing intent result. BGP communities carry policy metadata without directly supplying next-hop reachability.
C:Received and advertised route sets satisfy their separate intended controls. This validates BGP import versus export policy direction but does not directly demonstrate the required BGP communities tagging routing intent result. BGP communities carry policy metadata without directly supplying next-hop reachability.
Question 129
A misconfigured RT causes tenant A MAC routes to appear in tenant B routing context. Select THREE statements that correctly combine the EVPN route target import export scope implementation, its evidence, or its governing principle.
- Set the same switch hostname on all VTEPs and expect import policies to match automatically.
- Only matching tenant EVPN routes import and authorized MAC learning succeeds.
- Configure supported all-active multihoming mode and compatible LAG or ESI settings.
- EVPN route targets control distribution membership independently of VNI packet encapsulation.
- Validate supported DF election and its per-segment or VLAN role assignments.
- Set compatible route-target import and export policy for intended EVPN instances.
Explanation
Correct Answers
B:Only matching tenant EVPN routes import and authorized MAC learning succeeds. This is direct observable evidence for EVPN route target import export scope.
D:EVPN route targets control distribution membership independently of VNI packet encapsulation. It explains the action and observed outcome for EVPN route target import export scope.
F:Set compatible route-target import and export policy for intended EVPN instances. This is the intended implementation action for EVPN route target import export scope.
Incorrect Answers
A:Set the same switch hostname on all VTEPs and expect import policies to match automatically. This would not be an appropriate EVPN route target import export scope decision. Excessively broad RT import can expose tenant routes or create wrong forwarding entries.
C:Configure supported all-active multihoming mode and compatible LAG or ESI settings. This belongs to EVPN all-active multihoming forwarding, not the specified EVPN route target import export scope operation. EVPN route targets control distribution membership independently of VNI packet encapsulation.
E:Validate supported DF election and its per-segment or VLAN role assignments. This belongs to EVPN designated forwarder DF for BUM, not the specified EVPN route target import export scope operation. EVPN route targets control distribution membership independently of VNI packet encapsulation.
Question 130
A new ASM group has receivers but no RP information on branch routers. After deploying the recommended PIM sparse-mode RP shared tree change, which result MOST directly verifies success?
- Isolated endpoints reach the intended shared gateway but not peer isolated ports.
- Multicast frames reach receiver ports instead of every port by default.
- Every receiver-facing router resolves the same intended RP for each permitted group.
- (*,G) joins establish a shared tree via the intended RP and receivers get the stream.
Explanation
Correct Answer
D:(*,G) joins establish a shared tree via the intended RP and receivers get the stream. This is the directly observable outcome for PIM sparse-mode RP shared tree. Sparse-mode ASM commonly uses an RP to establish initial shared-tree multicast state.
Incorrect Answers
A:Isolated endpoints reach the intended shared gateway but not peer isolated ports. This validates Private VLAN isolated port separation but does not directly demonstrate the required PIM sparse-mode RP shared tree result. Sparse-mode ASM commonly uses an RP to establish initial shared-tree multicast state.
B:Multicast frames reach receiver ports instead of every port by default. This validates IGMP snooping access-port replication but does not directly demonstrate the required PIM sparse-mode RP shared tree result. Sparse-mode ASM commonly uses an RP to establish initial shared-tree multicast state.
C:Every receiver-facing router resolves the same intended RP for each permitted group. This validates Static RP mapping group range but does not directly demonstrate the required PIM sparse-mode RP shared tree result. Sparse-mode ASM commonly uses an RP to establish initial shared-tree multicast state.
