Juniper JN0-650 Practice Test 70
Question 690
Some VLANs loop after the peer changes STP mode or tagging. Select TWO statements that correctly combine the VSTP interoperation and VLAN tagging implementation, its evidence, or its governing principle.
- Align supported outer-tag TPID and VLAN-stacking configuration across participating devices.
- Validate compatible VSTP participation per VLAN and consistent trunk membership.
- Correct VLAN STP instances exchange control frames and maintain loop-free forwarding.
- Configure only OSPF neighbor authentication and assume tagged STP BPDUs become compatible.
- Create controlled firewall-filter-based VLAN classification on eligible ingress interfaces.
Explanation
Correct Answers
B:Validate compatible VSTP participation per VLAN and consistent trunk membership. This is the intended implementation action for VSTP interoperation and VLAN tagging.
C:Correct VLAN STP instances exchange control frames and maintain loop-free forwarding. This is direct observable evidence for VSTP interoperation and VLAN tagging.
Incorrect Answers
A:Align supported outer-tag TPID and VLAN-stacking configuration across participating devices. This belongs to QinQ tag protocol EtherType compatibility, not the specified VSTP interoperation and VLAN tagging operation. Per-VLAN STP compatibility depends on VLAN tagging and protocol expectations.
D:Configure only OSPF neighbor authentication and assume tagged STP BPDUs become compatible. This would not be an appropriate VSTP interoperation and VLAN tagging decision. Different BPDU handling per VLAN can leave only some VLANs unprotected.
E:Create controlled firewall-filter-based VLAN classification on eligible ingress interfaces. This belongs to Filter-based VLAN assignment, not the specified VSTP interoperation and VLAN tagging operation. Per-VLAN STP compatibility depends on VLAN tagging and protocol expectations.
Question 691
A VLAN disappears from a transit because one switch does not participate in dynamic registration. Which next investigation or correction is MOST appropriate?
- Capture VLAN-specific BPDUs and compare configured VSTP VLAN lists.
- Configure static OSPF route summaries and expect MVRP VLAN registration to follow.
- Inspect MVRP registration status and learned dynamic VLAN entries.
- Inspect MSTP port role state path cost and root ID.
Explanation
Correct Answer
C:Inspect MVRP registration status and learned dynamic VLAN entries. This checks whether eligible VLAN registration propagates and the intended traffic crosses participating trunks.
Incorrect Answers
A:Capture VLAN-specific BPDUs and compare configured VSTP VLAN lists. That check applies chiefly to VSTP interoperation and VLAN tagging, not the current MVRP dynamic VLAN registration issue. MVRP advertises VLAN registration dynamically between compatible bridge ports.
B:Configure static OSPF route summaries and expect MVRP VLAN registration to follow. That bypass leaves the MVRP dynamic VLAN registration issue unresolved. Incomplete participation can leave VLANs unregistered on intermediate trunks.
D:Inspect MSTP port role state path cost and root ID. That check applies chiefly to MSTP root port and alternate path, not the current MVRP dynamic VLAN registration issue. MVRP advertises VLAN registration dynamically between compatible bridge ports.
Question 692
Routes are received but should be disallowed locally without altering peer advertisement. After deploying the recommended BGP import versus export policy direction change, which result MOST directly verifies success?
- Received and advertised route sets satisfy their separate intended controls.
- The upstream accepts advertised MED values with understood decision constraints.
- Loopback-sourced peers establish across the intended hop count and remain reachable.
- The switch and phone discover each other with accurate system and port details.
Explanation
Correct Answer
A:Received and advertised route sets satisfy their separate intended controls. This is the directly observable outcome for BGP import versus export policy direction. Import changes received-route eligibility while export governs what is sent to peers.
Incorrect Answers
B:The upstream accepts advertised MED values with understood decision constraints. This validates BGP MED inbound traffic hint but does not directly demonstrate the required BGP import versus export policy direction result. Import changes received-route eligibility while export governs what is sent to peers.
C:Loopback-sourced peers establish across the intended hop count and remain reachable. This validates BGP loopback peering and multihop but does not directly demonstrate the required BGP import versus export policy direction result. Import changes received-route eligibility while export governs what is sent to peers.
D:The switch and phone discover each other with accurate system and port details. This validates LLDP neighbor advertisement but does not directly demonstrate the required BGP import versus export policy direction result. Import changes received-route eligibility while export governs what is sent to peers.
Question 693
A redistribution design unexpectedly sets an incomplete BGP origin and affects ranking. Which next investigation or correction is MOST appropriate?
- Compare full path selection diagnostics for both route candidates.
- Inspect show bgp neighbor and firewall filter counters for TCP179.
- Rewrite the Ethernet source MAC and expect that to alter BGP origin attribute.
- Inspect negotiated families and show route table inet.0 protocol bgp.
Explanation
Correct Answer
A:Compare full path selection diagnostics for both route candidates. This checks whether chosen path reflects the complete ordered decision process rather than origin alone.
Incorrect Answers
B:Inspect show bgp neighbor and firewall filter counters for TCP179. That check applies chiefly to BGP TCP 179 and firewall reachability, not the current BGP origin attribute influence issue. BGP origin distinguishes IGP EGP and incomplete values with limited relative ranking.
C:Rewrite the Ethernet source MAC and expect that to alter BGP origin attribute. That bypass leaves the BGP origin attribute influence issue unresolved. Treating origin as more important than LOCAL_PREF or AS_PATH yields incorrect predictions.
D:Inspect negotiated families and show route table inet.0 protocol bgp. That check applies chiefly to BGP NLRI IPv4 unicast inet family, not the current BGP origin attribute influence issue. BGP origin distinguishes IGP EGP and incomplete values with limited relative ranking.
Question 694
A new point-to-point IPv6 interface has global addresses but missing OSPFv3 enablement. Which technical principle BEST explains the OSPFv3 IPv6 link-local neighbor formation decision?
- OSPF interarea summarization originates at area boundaries with reachability tradeoffs.
- OSPFv2 and OSPFv3 have related SPF logic but separate protocol and address-family configuration.
- MSDP can exchange source-active awareness across ASM RP domains.
- OSPFv3 IPv6 adjacencies depend on link-local reachability and protocol enablement.
Explanation
Correct Answer
D:OSPFv3 IPv6 adjacencies depend on link-local reachability and protocol enablement. In this situation, the relevant action is to configure supported OSPFv3 interface participation and compatible neighbor settings.
Incorrect Answers
A:OSPF interarea summarization originates at area boundaries with reachability tradeoffs. That principle is related to OSPF interarea route summarization, not the main OSPFv3 IPv6 link-local neighbor formation choice. Global IPv6 addressing alone does not guarantee OSPFv3 routing.
B:OSPFv2 and OSPFv3 have related SPF logic but separate protocol and address-family configuration. That principle is related to OSPFv2 versus OSPFv3 operations, not the main OSPFv3 IPv6 link-local neighbor formation choice. Global IPv6 addressing alone does not guarantee OSPFv3 routing.
C:MSDP can exchange source-active awareness across ASM RP domains. That principle is related to MSDP source active exchange, not the main OSPFv3 IPv6 link-local neighbor formation choice. Global IPv6 addressing alone does not guarantee OSPFv3 routing.
Question 695
An enterprise core uses internal traffic classes but ISP handoff requires different DSCP code points. Which configuration or operational step BEST meets the stated requirement?
- Increase IP precedence on the input without checking outbound rewrite association.
- Configure appropriate rewrite rules mapping forwarding class and PLP to egress DSCP.
- Configure suitable RED or WRED drop profiles and map PLP to planned thresholds.
- Tune supported scheduler buffer sizes consistent with measured burst requirements.
Explanation
Correct Answer
B:Configure appropriate rewrite rules mapping forwarding class and PLP to egress DSCP. Junos rewrite rules use internal forwarding class and PLP to set outbound header bits. The expected validation is that outgoing packet captures show the expected DSCP values on the selected interface.
Incorrect Answers
A:Increase IP precedence on the input without checking outbound rewrite association. This is a risky or ineffective shortcut for DSCP egress rewrite rules. Ingress classification does not itself guarantee downstream marking consistency.
C:Configure suitable RED or WRED drop profiles and map PLP to planned thresholds. This addresses RED WRED drop profile thresholds rather than the required DSCP egress rewrite rules decision. Junos rewrite rules use internal forwarding class and PLP to set outbound header bits.
D:Tune supported scheduler buffer sizes consistent with measured burst requirements. This addresses Queue buffer-size allocation rather than the required DSCP egress rewrite rules decision. Junos rewrite rules use internal forwarding class and PLP to set outbound header bits.
Question 696
A new iBGP route-reflector cluster learns prefixes whose next hop exists only at the exit router. Which technical principle BEST explains the iBGP next-hop-self on edge decision?
- iBGP may preserve external next-hop attributes unless policy changes them.
- BA classification interprets existing packet markings and assigns forwarding class and loss priority.
- BGP address families determine which NLRI types may be exchanged.
- BGP AS_PATH records AS traversal and participates in loop prevention and path selection.
Explanation
Correct Answer
A:IBGP may preserve external next-hop attributes unless policy changes them. In this situation, the relevant action is to apply a scoped BGP next-hop-self or next-hop resolution design at the appropriate edge.
Incorrect Answers
B:BA classification interprets existing packet markings and assigns forwarding class and loss priority. That principle is related to Junos ingress BA DSCP classifier, not the main iBGP next-hop-self on edge choice. Unreachable preserved eBGP next hops can make internally advertised routes unusable.
C:BGP address families determine which NLRI types may be exchanged. That principle is related to BGP NLRI IPv4 unicast inet family, not the main iBGP next-hop-self on edge choice. Unreachable preserved eBGP next hops can make internally advertised routes unusable.
D: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 iBGP next-hop-self on edge choice. Unreachable preserved eBGP next hops can make internally advertised routes unusable.
Question 697
An IP phone connected to an EX switch is not listed as an LLDP neighbor. Which configuration or operational step BEST meets the stated requirement?
- Enable supported LLDP transmit and receive functions on the intended interface.
- Configure BGP route reflection and expect LLDP neighbor advertisements.
- Apply a deliberate trust boundary and separate PC and voice VLAN access policies.
- Configure supported LLDP-MED voice VLAN network policy for the relevant ports.
Explanation
Correct Answer
A:Enable supported LLDP transmit and receive functions on the intended interface. LLDP provides Layer 2 neighbor discovery independent of IP routing. The expected validation is that the switch and phone discover each other with accurate system and port details.
Incorrect Answers
B:Configure BGP route reflection and expect LLDP neighbor advertisements. This is a risky or ineffective shortcut for LLDP neighbor advertisement. A physically connected device without LLDP exchange cannot receive LLDP-based network policy.
C:Apply a deliberate trust boundary and separate PC and voice VLAN access policies. This addresses Phone and PC shared switch-port security rather than the required LLDP neighbor advertisement decision. LLDP provides Layer 2 neighbor discovery independent of IP routing.
D:Configure supported LLDP-MED voice VLAN network policy for the relevant ports. This addresses LLDP-MED voice network policy rather than the required LLDP neighbor advertisement decision. LLDP provides Layer 2 neighbor discovery independent of IP routing.
Question 698
A routed network has asymmetric unicast topology that causes multicast traffic to be dropped. Which technical principle BEST explains the Multicast RPF shortest reverse path check decision?
- EVPN Type2 routes advertise host MAC addresses with optional IP binding.
- Multicast RPF prevents loops by checking the expected route toward the source or RP.
- Source Specific Multicast builds source-directed trees without an ASM rendezvous point.
- PIM establishes multicast router adjacencies independently of host IGMP group membership.
Explanation
Correct Answer
B:Multicast RPF prevents loops by checking the expected route toward the source or RP. In this situation, the relevant action is to align multicast RPF expectations with unicast or configured multicast routing topology.
Incorrect Answers
A:EVPN Type2 routes advertise host MAC addresses with optional IP binding. That principle is related to EVPN Type2 MAC IP advertisement, not the main Multicast RPF shortest reverse path check choice. A valid group membership cannot compensate for a failed RPF incoming-interface check.
C:Source Specific Multicast builds source-directed trees without an ASM rendezvous point. That principle is related to SSM without rendezvous point, not the main Multicast RPF shortest reverse path check choice. A valid group membership cannot compensate for a failed RPF incoming-interface check.
D:PIM establishes multicast router adjacencies independently of host IGMP group membership. That principle is related to PIM sparse-mode neighbor discovery, not the main Multicast RPF shortest reverse path check choice. A valid group membership cannot compensate for a failed RPF incoming-interface check.
Question 699
Packets are correctly assigned to a named forwarding class but reach the wrong hardware output queue. After deploying the recommended Junos forwarding class to queue mapping change, which result MOST directly verifies success?
- Approved voice packets gain the intended forwarding class while bulk packets do not.
- Phone RTP and signaling reach voice network while PC traffic stays in data segment.
- Each packet class reaches the planned output queue with expected counters.
- Bursty traffic sees acceptable loss with controlled memory usage.
Explanation
Correct Answer
C:Each packet class reaches the planned output queue with expected counters. This is the directly observable outcome for Junos forwarding class to queue mapping. Forwarding classes express per-hop traffic treatment and map to transmission queues.
Incorrect Answers
A: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 Junos forwarding class to queue mapping result. Forwarding classes express per-hop traffic treatment and map to transmission queues.
B:Phone RTP and signaling reach voice network while PC traffic stays in data segment. This validates Voice VLAN tagged versus PC data traffic but does not directly demonstrate the required Junos forwarding class to queue mapping result. Forwarding classes express per-hop traffic treatment and map to transmission queues.
D:Bursty traffic sees acceptable loss with controlled memory usage. This validates Queue buffer-size allocation but does not directly demonstrate the required Junos forwarding class to queue mapping result. Forwarding classes express per-hop traffic treatment and map to transmission queues.
Question 700
A dual-attached server should use both healthy access links through two EVPN leaves. Which configuration or operational step BEST meets the stated requirement?
- Configure supported all-active multihoming mode and compatible LAG or ESI settings.
- Configure consistent supported VLAN-to-VNI mapping in the intended routing instances.
- Disable split-horizon protection to obtain unbounded active-active forwarding.
- Set compatible route-target import and export policy for intended EVPN instances.
Explanation
Correct Answer
A:Configure supported all-active multihoming mode and compatible LAG or ESI settings. EVPN all-active multihoming can use parallel forwarding paths with designated loop protection. The expected validation is that traffic can use eligible multihomed links while loss of one link preserves connectivity.
Incorrect Answers
B:Configure consistent supported VLAN-to-VNI mapping in the intended routing instances. This addresses VXLAN VNI to VLAN association rather than the required EVPN all-active multihoming forwarding decision. EVPN all-active multihoming can use parallel forwarding paths with designated loop protection.
C:Disable split-horizon protection to obtain unbounded active-active forwarding. This is a risky or ineffective shortcut for EVPN all-active multihoming forwarding. Treating both uplinks as independent uncoordinated bridges can form duplication or loops.
D:Set compatible route-target import and export policy for intended EVPN instances. This addresses EVPN route target import export scope rather than the required EVPN all-active multihoming forwarding decision. EVPN all-active multihoming can use parallel forwarding paths with designated loop protection.
