Juniper JN0-650 Practice Test 55
Question 540
A large webcast is flooding every access port in a multicast-enabled VLAN. Which configuration or operational step BEST meets the stated requirement?
- Align source reachability and any approved multicast RPF policy with actual topology.
- Enable appropriate IGMP snooping and maintain valid querier membership learning.
- Select appropriate IPv6 multicast addressing and scope behavior for intended receivers.
- Replace IGMP snooping with BGP prefix aggregation to control Layer 2 ports.
Explanation
Correct Answer
B:Enable appropriate IGMP snooping and maintain valid querier membership learning. IGMP snooping uses observed host joins to constrain layer-2 multicast replication. The expected validation is that multicast frames reach receiver ports instead of every port by default.
Incorrect Answers
A:Align source reachability and any approved multicast RPF policy with actual topology. This addresses Multicast source route policy and RPF rather than the required IGMP snooping access-port replication decision. IGMP snooping uses observed host joins to constrain layer-2 multicast replication.
C:Select appropriate IPv6 multicast addressing and scope behavior for intended receivers. This addresses IPv6 multicast scope and group use rather than the required IGMP snooping access-port replication decision. IGMP snooping uses observed host joins to constrain layer-2 multicast replication.
D:Replace IGMP snooping with BGP prefix aggregation to control Layer 2 ports. This is a risky or ineffective shortcut for IGMP snooping access-port replication. Missing membership state or wrong querier behavior can flood or blackhole multicast.
Question 541
A misconfigured RT causes tenant A MAC routes to appear in tenant B routing context. Which next investigation or correction is MOST appropriate?
- Compare received extended communities and imported EVPN instance routes.
- Trace VXLAN BUM packet source ESI and egress eligibility on both peers.
- Set the same switch hostname on all VTEPs and expect import policies to match automatically.
- Inspect active and standby Ethernet segment status during a link failover.
Explanation
Correct Answer
A:Compare received extended communities and imported EVPN instance routes. This checks whether only matching tenant EVPN routes import and authorized MAC learning succeeds.
Incorrect Answers
B:Trace VXLAN BUM packet source ESI and egress eligibility on both peers. That check applies chiefly to EVPN multihoming split horizon loop avoidance, not the current EVPN route target import export scope issue. EVPN route targets control distribution membership independently of VNI packet encapsulation.
C:Set the same switch hostname on all VTEPs and expect import policies to match automatically. That bypass leaves the EVPN route target import export scope issue unresolved. Excessively broad RT import can expose tenant routes or create wrong forwarding entries.
D:Inspect active and standby Ethernet segment status during a link failover. That check applies chiefly to EVPN single-active multihoming access mode, not the current EVPN route target import export scope issue. EVPN route targets control distribution membership independently of VNI packet encapsulation.
Question 542
A malicious workstation marks all packets as expedited voice using an attached phone switch. Which technical principle BEST explains the Phone and PC shared switch-port security decision?
- Private VLAN isolation provides Layer 2 separation within a shared primary VLAN.
- Phone pass-through ports need explicit data security and QoS trust design.
- LLDP-MED can convey voice network policy including VLAN and priority information.
- IEEE PoE total power budget and per-port allocation constrain powered endpoints.
Explanation
Correct Answer
B:Phone pass-through ports need explicit data security and QoS trust design. In this situation, the relevant action is to apply a deliberate trust boundary and separate PC and voice VLAN access policies.
Incorrect Answers
A:Private VLAN isolation provides Layer 2 separation within a shared primary VLAN. That principle is related to Private VLAN isolated port separation, not the main Phone and PC shared switch-port security choice. Trusting every attached PC's markings can consume voice queues and bypass policy.
C:LLDP-MED can convey voice network policy including VLAN and priority information. That principle is related to LLDP-MED voice priority signaling, not the main Phone and PC shared switch-port security choice. Trusting every attached PC's markings can consume voice queues and bypass policy.
D:IEEE PoE total power budget and per-port allocation constrain powered endpoints. That principle is related to PoE power budget switch capacity, not the main Phone and PC shared switch-port security choice. Trusting every attached PC's markings can consume voice queues and bypass policy.
Question 543
An RR session is Established for inet unicast but not for the EVPN address family. Which technical principle BEST explains the BGP EVPN address-family peer negotiation decision?
- EVPN uses MP-BGP control-plane signaling separate from ordinary IPv4 unicast reachability.
- Single-active multihoming deliberately avoids parallel forwarding on a shared segment.
- EVPN DF controls multihomed access delivery of broadcast unknown-unicast and multicast traffic.
- A policer meters traffic and may drop or remark traffic exceeding its limits.
Explanation
Correct Answer
A:EVPN uses MP-BGP control-plane signaling separate from ordinary IPv4 unicast reachability. In this situation, the relevant action is to enable compatible BGP EVPN signaling on the appropriate peers with scoped policy.
Incorrect Answers
B:Single-active multihoming deliberately avoids parallel forwarding on a shared segment. That principle is related to EVPN single-active multihoming access mode, not the main BGP EVPN address-family peer negotiation choice. Having an IP-connected VTEP does not mean its peer negotiates EVPN NLRI.
C:EVPN DF controls multihomed access delivery of broadcast unknown-unicast and multicast traffic. That principle is related to EVPN designated forwarder DF for BUM, not the main BGP EVPN address-family peer negotiation choice. Having an IP-connected VTEP does not mean its peer negotiates EVPN NLRI.
D:A policer meters traffic and may drop or remark traffic exceeding its limits. That principle is related to Junos ingress policer rate limit, not the main BGP EVPN address-family peer negotiation choice. Having an IP-connected VTEP does not mean its peer negotiates EVPN NLRI.
Question 544
An application receives bursts only after repeated PIM state clearing. Select TWO statements that correctly combine the Multicast troubleshooting separate control and data planes implementation, its evidence, or its governing principle.
- A consistent state chain from source to receivers explains successful data delivery.
- Align source reachability and any approved multicast RPF policy with actual topology.
- Correlate multicast route incoming interface with outgoing-interface list and group state.
- Troubleshoot source activity group membership RPF PIM joins and data packet counters in order.
- Reboot all switching devices every time an IGMP group table contains an entry.
Explanation
Correct Answers
A:A consistent state chain from source to receivers explains successful data delivery. This is direct observable evidence for Multicast troubleshooting separate control and data planes.
D:Troubleshoot source activity group membership RPF PIM joins and data packet counters in order. This is the intended implementation action for Multicast troubleshooting separate control and data planes.
Incorrect Answers
B:Align source reachability and any approved multicast RPF policy with actual topology. This belongs to Multicast source route policy and RPF, not the specified Multicast troubleshooting separate control and data planes operation. Multicast involves host membership router tree state and actual forwarding traffic.
C:Correlate multicast route incoming interface with outgoing-interface list and group state. This belongs to Multicast routing table incoming outgoing lists, not the specified Multicast troubleshooting separate control and data planes operation. Multicast involves host membership router tree state and actual forwarding traffic.
E:Reboot all switching devices every time an IGMP group table contains an entry. This would not be an appropriate Multicast troubleshooting separate control and data planes decision. Seeing an IGMP group alone does not prove an active source or valid routed data path.
Question 545
A Junos route exists in an OSPF LSDB but does not become an active route as expected. Which technical principle BEST explains the OSPF routing policy import filtering decision?
- Local route preference or policy and OSPF flooding are distinct decisions.
- OSPF database exchange can stall when peers disagree on interface MTU.
- BGP AS_PATH records AS traversal and participates in loop prevention and path selection.
- Point-to-point OSPF interfaces do not use broadcast-network DR election.
Explanation
Correct Answer
A:Local route preference or policy and OSPF flooding are distinct decisions. In this situation, the relevant action is to apply supported route policy at the correct Junos OSPF import or RIB-selection control.
Incorrect Answers
B:OSPF database exchange can stall when peers disagree on interface MTU. That principle is related to OSPF interface MTU mismatch, not the main OSPF routing policy import filtering choice. Mistaking local import rejection for universal LSA suppression produces false reachability assumptions.
C:BGP AS_PATH records AS traversal and participates in loop prevention and path selection. That principle is related to BGP AS_PATH loop prevention and length, not the main OSPF routing policy import filtering choice. Mistaking local import rejection for universal LSA suppression produces false reachability assumptions.
D:Point-to-point OSPF interfaces do not use broadcast-network DR election. That principle is related to OSPF point-to-point network type, not the main OSPF routing policy import filtering choice. Mistaking local import rejection for universal LSA suppression produces false reachability assumptions.
Question 546
A support team confuses EAPOL exchange between endpoint and switch with RADIUS exchange to the AAA server. Which technical principle BEST explains the 802.1X supplicant authenticator RADIUS roles decision?
- EAP credential validation requires mutual compatible authentication and trust policy.
- Guest VLAN authorizes limited access for eligible unauthenticated clients.
- BGP path eligibility depends on successful next-hop resolution in the routing table.
- 802.1X separates supplicant authenticator and authentication server roles.
Explanation
Correct Answer
D:802.1X separates supplicant authenticator and authentication server roles. In this situation, the relevant action is to configure supported 802.1X authenticator on edge ports and RADIUS server reachability.
Incorrect Answers
A:EAP credential validation requires mutual compatible authentication and trust policy. That principle is related to 802.1X EAP authentication credential validation, not the main 802.1X supplicant authenticator RADIUS roles choice. Treating RADIUS as an EAPOL packet directly emitted by the laptop prevents correct troubleshooting.
B:Guest VLAN authorizes limited access for eligible unauthenticated clients. That principle is related to Guest VLAN for unauthenticated clients, not the main 802.1X supplicant authenticator RADIUS roles choice. Treating RADIUS as an EAPOL packet directly emitted by the laptop prevents correct troubleshooting.
C: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 802.1X supplicant authenticator RADIUS roles choice. Treating RADIUS as an EAPOL packet directly emitted by the laptop prevents correct troubleshooting.
Question 547
A switch supplies basic PoE but the device's extension module remains unavailable. Which technical principle BEST explains the PoE class discovery and allocation decision?
- Multiple authentication methods must be composed without creating a bypass path.
- LLDP provides Layer 2 neighbor discovery independent of IP routing.
- IEEE PoE total power budget and per-port allocation constrain powered endpoints.
- PoE detection classification and allocation are distinct from Ethernet packet switching.
Explanation
Correct Answer
D:PoE detection classification and allocation are distinct from Ethernet packet switching. In this situation, the relevant action is to verify supported PoE power classes and power negotiation for the specific phone model.
Incorrect Answers
A: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 PoE class discovery and allocation choice. Assuming any PoE-capable port supplies every device's requested wattage is unsafe.
B:LLDP provides Layer 2 neighbor discovery independent of IP routing. That principle is related to LLDP neighbor advertisement, not the main PoE class discovery and allocation choice. Assuming any PoE-capable port supplies every device's requested wattage is unsafe.
C:IEEE PoE total power budget and per-port allocation constrain powered endpoints. That principle is related to PoE power budget switch capacity, not the main PoE class discovery and allocation choice. Assuming any PoE-capable port supplies every device's requested wattage is unsafe.
Question 548
A customer edge inserts stacked tags that an intermediate switch drops as malformed. Which next investigation or correction is MOST appropriate?
- Decode Ethernet EtherType and both VLAN IDs in packet captures.
- Inspect interface mode VLAN members and the learned MAC table.
- Check filter terms counters and learned VLAN association for sample ingress frames.
- Modify the DSCP value and expect the outer 802.1Q tag EtherType to change.
Explanation
Correct Answer
A:Decode Ethernet EtherType and both VLAN IDs in packet captures. This checks whether two-tagged frames pass through provider ports with the expected EtherType.
Incorrect Answers
B:Inspect interface mode VLAN members and the learned MAC table. That check applies chiefly to Ethernet access interface VLAN membership, not the current QinQ tag protocol EtherType compatibility issue. VLAN stacking requires compatible tag interpretation and consistent port behavior.
C:Check filter terms counters and learned VLAN association for sample ingress frames. That check applies chiefly to Filter-based VLAN assignment, not the current QinQ tag protocol EtherType compatibility issue. VLAN stacking requires compatible tag interpretation and consistent port behavior.
D:Modify the DSCP value and expect the outer 802.1Q tag EtherType to change. That bypass leaves the QinQ tag protocol EtherType compatibility issue unresolved. Mismatched TPID assumptions can cause customer frames to be dropped.
Question 549
A support team confuses EAPOL exchange between endpoint and switch with RADIUS exchange to the AAA server. Which next investigation or correction is MOST appropriate?
- Verify assigned VLAN and ACLs with valid employee and guest test clients.
- Capture EAPOL on access link and RADIUS transactions toward AAA host.
- Change the OSPF router ID and assume user 802.1X certificates become valid.
- Test authorized and unauthorized MACs behind the same physical port.
Explanation
Correct Answer
B:Capture EAPOL on access link and RADIUS transactions toward AAA host. This checks whether a compliant supplicant authenticates and the switch authorizes its port policy.
Incorrect Answers
A:Verify assigned VLAN and ACLs with valid employee and guest test clients. That check applies chiefly to Guest VLAN for unauthenticated clients, not the current 802.1X supplicant authenticator RADIUS roles issue. 802.1X separates supplicant authenticator and authentication server roles.
C:Change the OSPF router ID and assume user 802.1X certificates become valid. That bypass leaves the 802.1X supplicant authenticator RADIUS roles issue unresolved. Treating RADIUS as an EAPOL packet directly emitted by the laptop prevents correct troubleshooting.
D:Test authorized and unauthorized MACs behind the same physical port. That check applies chiefly to 802.1X multi-supplicant port control, not the current 802.1X supplicant authenticator RADIUS roles issue. 802.1X separates supplicant authenticator and authentication server roles.
Question 550
A team expects packet-by-packet round robin across BGP equal-cost interfaces. Which technical principle BEST explains the BGP ECMP per-flow hashing decision?
- ECMP commonly hashes traffic flows rather than balancing individual packets deterministically.
- Junos routing policy evaluates ordered terms and control-flow actions.
- BGP AS_PATH records AS traversal and participates in loop prevention and path selection.
- Phone access-port design can carry tagged voice and untagged data for separate policies.
Explanation
Correct Answer
A:ECMP commonly hashes traffic flows rather than balancing individual packets deterministically. In this situation, the relevant action is to validate supported forwarding-table hashing and load distribution across many distinct flows.
Incorrect Answers
B:Junos routing policy evaluates ordered terms and control-flow actions. That principle is related to Junos BGP policy term matching, not the main BGP ECMP per-flow hashing choice. Predicting equal utilization for a single heavy flow misunderstands per-flow selection.
C:BGP AS_PATH records AS traversal and participates in loop prevention and path selection. That principle is related to BGP AS_PATH loop prevention and length, not the main BGP ECMP per-flow hashing choice. Predicting equal utilization for a single heavy flow misunderstands per-flow selection.
D:Phone access-port design can carry tagged voice and untagged data for separate policies. That principle is related to Voice VLAN tagged versus PC data traffic, not the main BGP ECMP per-flow hashing choice. Predicting equal utilization for a single heavy flow misunderstands per-flow selection.
