Juniper JN0-650 Practice Test 69
Question 680
A dual-homed server's access segment must be advertised across two EVPN leaf peers. After deploying the recommended EVPN Type1 Ethernet auto discovery change, which result MOST directly verifies success?
- Remote peers recognize Ethernet segment participation and respond to advertised withdrawals.
- BUM frames are not looped back to the originating Ethernet segment.
- Peers agree on a common Ethernet segment and relevant EVPN ES routes.
- Queue statistics show probabilistic early drops according to class and PLP settings.
Explanation
Correct Answer
A:Remote peers recognize Ethernet segment participation and respond to advertised withdrawals. This is the directly observable outcome for EVPN Type1 Ethernet auto discovery. Type1 Ethernet A-D routes signal Ethernet segment reachability and support multihoming convergence.
Incorrect Answers
B:BUM frames are not looped back to the originating Ethernet segment. This validates EVPN multihoming split horizon loop avoidance but does not directly demonstrate the required EVPN Type1 Ethernet auto discovery result. Type1 Ethernet A-D routes signal Ethernet segment reachability and support multihoming convergence.
C:Peers agree on a common Ethernet segment and relevant EVPN ES routes. This validates Ethernet segment identifier ESI consistency but does not directly demonstrate the required EVPN Type1 Ethernet auto discovery result. Type1 Ethernet A-D routes signal Ethernet segment reachability and support multihoming convergence.
D:Queue statistics show probabilistic early drops according to class and PLP settings. This validates RED WRED drop profile thresholds but does not directly demonstrate the required EVPN Type1 Ethernet auto discovery result. Type1 Ethernet A-D routes signal Ethernet segment reachability and support multihoming convergence.
Question 681
A designated-forwarder change causes duplicate broadcast frames toward the dual-homed server. Select TWO statements that correctly combine the EVPN designated forwarder DF for BUM implementation, its evidence, or its governing principle.
- Select the OSPF DR and assume it automatically becomes EVPN DF for every Ethernet segment.
- Only the authorized DF forwards designated BUM traffic toward the shared segment.
- Set compatible route-target import and export policy for intended EVPN instances.
- Configure consistent supported VLAN-to-VNI mapping in the intended routing instances.
- Validate supported DF election and its per-segment or VLAN role assignments.
Explanation
Correct Answers
B:Only the authorized DF forwards designated BUM traffic toward the shared segment. This is direct observable evidence for EVPN designated forwarder DF for BUM.
E:Validate supported DF election and its per-segment or VLAN role assignments. This is the intended implementation action for EVPN designated forwarder DF for BUM.
Incorrect Answers
A:Select the OSPF DR and assume it automatically becomes EVPN DF for every Ethernet segment. This would not be an appropriate EVPN designated forwarder DF for BUM decision. Incorrect DF state may duplicate BUM traffic or strand a segment after failure.
C:Set compatible route-target import and export policy for intended EVPN instances. This belongs to EVPN route target import export scope, not the specified EVPN designated forwarder DF for BUM operation. EVPN DF controls multihomed access delivery of broadcast unknown-unicast and multicast traffic.
D:Configure consistent supported VLAN-to-VNI mapping in the intended routing instances. This belongs to VXLAN VNI to VLAN association, not the specified EVPN designated forwarder DF for BUM operation. EVPN DF controls multihomed access delivery of broadcast unknown-unicast and multicast traffic.
Question 682
An RP address is configured but not reachable via the unicast underlay. Which technical principle BEST explains the Static RP mapping group range decision?
- Sparse-mode ASM commonly uses an RP to establish initial shared-tree multicast state.
- RPF uses source or RP reachability and can change when unicast routing changes.
- RP mapping and unicast RP reachability are separate multicast requirements.
- OSPF neighbors exchange compatible Hellos before database synchronization.
Explanation
Correct Answer
C:RP mapping and unicast RP reachability are separate multicast requirements. In this situation, the relevant action is to apply a consistent scoped RP mapping with verified routing to the RP.
Incorrect Answers
A:Sparse-mode ASM commonly uses an RP to establish initial shared-tree multicast state. That principle is related to PIM sparse-mode RP shared tree, not the main Static RP mapping group range choice. Inconsistent RP views can divide a single group into separate multicast trees.
B:RPF uses source or RP reachability and can change when unicast routing changes. That principle is related to Multicast source route policy and RPF, not the main Static RP mapping group range choice. Inconsistent RP views can divide a single group into separate multicast trees.
D:OSPF neighbors exchange compatible Hellos before database synchronization. That principle is related to OSPFv2 Hello and Dead timer adjacency, not the main Static RP mapping group range choice. Inconsistent RP views can divide a single group into separate multicast trees.
Question 683
Customer switches on opposite ends of a provider link stop seeing one another's control frames. Which technical principle BEST explains the L2PT customer BPDU tunneling decision?
- IPv4 multicast destination ranges are group identifiers rather than ordinary host addresses.
- Filter terms are evaluated in policy order subject to terminating actions.
- Ethernet switches learn source MACs per VLAN and flood unknown destinations until learned.
- L2PT encapsulates selected customer Layer 2 control frames across a provider domain.
Explanation
Correct Answer
D:L2PT encapsulates selected customer Layer 2 control frames across a provider domain. In this situation, the relevant action is to configure supported Layer 2 Protocol Tunneling for selected customer control protocols.
Incorrect Answers
A:IPv4 multicast destination ranges are group identifiers rather than ordinary host addresses. That principle is related to IPv4 multicast group address versus unicast, not the main L2PT customer BPDU tunneling choice. Without supported control protocol tunneling customer STP may not work across the service.
B:Filter terms are evaluated in policy order subject to terminating actions. That principle is related to Filter-based VLAN rule precedence, not the main L2PT customer BPDU tunneling choice. Without supported control protocol tunneling customer STP may not work across the service.
C:Ethernet switches learn source MACs per VLAN and flood unknown destinations until learned. That principle is related to Ethernet MAC learning and flooding, not the main L2PT customer BPDU tunneling choice. Without supported control protocol tunneling customer STP may not work across the service.
Question 684
An unauthorized access switch advertises a lower bridge ID and attempts to become root. Which configuration or operational step BEST meets the stated requirement?
- Configure a lower route preference in inet.0 and assume STP root cannot change.
- Configure root protection on links that must not receive superior root advertisements.
- Set explicit MSTI bridge priorities in the intended MST region.
- Configure community secondary roles and the appropriate promiscuous uplink association.
Explanation
Correct Answer
B:Configure root protection on links that must not receive superior root advertisements. Root protection guards designated bridge roles against unexpected root changes. The expected validation is that downstream superior BPDUs are rejected while the intended root remains authoritative.
Incorrect Answers
A:Configure a lower route preference in inet.0 and assume STP root cannot change. This is a risky or ineffective shortcut for Root protection on designated links. Allowing untrusted access switches to become STP root can shift and disrupt network paths.
C:Set explicit MSTI bridge priorities in the intended MST region. This addresses MSTP instance root selection rather than the required Root protection on designated links decision. Root protection guards designated bridge roles against unexpected root changes.
D:Configure community secondary roles and the appropriate promiscuous uplink association. This addresses Private VLAN community and promiscuous roles rather than the required Root protection on designated links decision. Root protection guards designated bridge roles against unexpected root changes.
Question 685
Frames for an unknown unicast destination flood within an intended VLAN. Which configuration or operational step BEST meets the stated requirement?
- Identify MAC learning state and remediate loops or incorrect topology.
- Configure appropriate VSTP VLAN-specific bridge priorities and port values.
- Configure an OSPF route filter to stop Layer 2 unknown-unicast flooding.
- Validate compatible VSTP participation per VLAN and consistent trunk membership.
Explanation
Correct Answer
A:Identify MAC learning state and remediate loops or incorrect topology. Ethernet switches learn source MACs per VLAN and flood unknown destinations until learned. The expected validation is that stable source MAC entries map to intended ingress interfaces and unknown floods are limited.
Incorrect Answers
B:Configure appropriate VSTP VLAN-specific bridge priorities and port values. This addresses VSTP per-VLAN root distribution rather than the required Ethernet MAC learning and flooding decision. Ethernet switches learn source MACs per VLAN and flood unknown destinations until learned.
C:Configure an OSPF route filter to stop Layer 2 unknown-unicast flooding. This is a risky or ineffective shortcut for Ethernet MAC learning and flooding. A loop can cause rapid MAC movement and high broadcast utilization.
D:Validate compatible VSTP participation per VLAN and consistent trunk membership. This addresses VSTP interoperation and VLAN tagging rather than the required Ethernet MAC learning and flooding decision. Ethernet switches learn source MACs per VLAN and flood unknown destinations until learned.
Question 686
After summarization an unintended disconnected subnet becomes reachable toward a null route. Which next investigation or correction is MOST appropriate?
- Compare interarea LSAs and test addresses at aggregate boundaries.
- Configure each access switch as a BGP route reflector to summarize OSPF areas.
- Verify per-interface network type and Hello processing at both endpoints.
- Inspect NSSA LSAs and translated external entries at the ABR.
Explanation
Correct Answer
A:Compare interarea LSAs and test addresses at aggregate boundaries. This checks whether other areas see the approved aggregate while required specifics remain reachable.
Incorrect Answers
B:Configure each access switch as a BGP route reflector to summarize OSPF areas. That bypass leaves the OSPF interarea route summarization issue unresolved. Overly broad summaries can attract traffic to absent component prefixes.
C:Verify per-interface network type and Hello processing at both endpoints. That check applies chiefly to OSPF point-to-point network type, not the current OSPF interarea route summarization issue. OSPF interarea summarization originates at area boundaries with reachability tradeoffs.
D:Inspect NSSA LSAs and translated external entries at the ABR. That check applies chiefly to OSPF NSSA type-seven translation, not the current OSPF interarea route summarization issue. OSPF interarea summarization originates at area boundaries with reachability tradeoffs.
Question 687
During an operational risk review, this situation is reported: A newly installed summary route changes the RPF interface for a heavily used group. If the underlying control is neglected, which failure would MOST directly follow?
- Without an effective querier snooping tables can lose active receiver ports.
- Incorrect or missing Type1 signaling can slow convergence or misrepresent ES availability.
- An unexpected source route preference may cause RPF failures after a control-plane change.
- Mis-scoped multicast can leak too far or fail to reach authorized hosts.
Explanation
Correct Answer
C:An unexpected source route preference may cause RPF failures after a control-plane change. RPF uses source or RP reachability and can change when unicast routing changes. A useful corrective investigation is to review show route source prefix versus show multicast route incoming interface.
Incorrect Answers
A:Without an effective querier snooping tables can lose active receiver ports. This is a IGMP querier on subscriber VLAN failure pattern, not the primary Multicast source route policy and RPF failure in this case. RPF uses source or RP reachability and can change when unicast routing changes.
B:Incorrect or missing Type1 signaling can slow convergence or misrepresent ES availability. This is a EVPN Type1 Ethernet auto discovery failure pattern, not the primary Multicast source route policy and RPF failure in this case. RPF uses source or RP reachability and can change when unicast routing changes.
D:Mis-scoped multicast can leak too far or fail to reach authorized hosts. This is a IPv6 multicast scope and group use failure pattern, not the primary Multicast source route policy and RPF failure in this case. RPF uses source or RP reachability and can change when unicast routing changes.
Question 688
After a route-filter change an unwanted IPv6 summary appears as an OSPFv3 external. Which next investigation or correction is MOST appropriate?
- Configure an IPv4-only match prefix and assert it necessarily matches IPv6 routes.
- Compare show route protocol ospf and interface metric contributions along both paths.
- Verify source route active state policy terms and destination inet6.0 routes.
- Inspect route hidden reason protocol database and configured policy chains.
Explanation
Correct Answer
C:Verify source route active state policy terms and destination inet6.0 routes. This checks whether remote IPv6 routers receive only the intended OSPFv3 external destinations.
Incorrect Answers
A:Configure an IPv4-only match prefix and assert it necessarily matches IPv6 routes. That bypass leaves the OSPFv3 routing policy for external IPv6 issue unresolved. Reusing an IPv4-only route filter can leave IPv6 export expectations unmet.
B:Compare show route protocol ospf and interface metric contributions along both paths. That check applies chiefly to OSPF path cost selection, not the current OSPFv3 routing policy for external IPv6 issue. Routing policy must match the relevant address family as well as eligible source routes.
D:Inspect route hidden reason protocol database and configured policy chains. That check applies chiefly to OSPF routing policy import filtering, not the current OSPFv3 routing policy for external IPv6 issue. Routing policy must match the relevant address family as well as eligible source routes.
Question 689
One branch has (S,G) state with no downstream outgoing interface after a topology change. Select THREE statements that correctly combine the Multicast routing table incoming outgoing lists implementation, its evidence, or its governing principle.
- Check only the BGP session up flag and conclude multicast delivery is healthy.
- Traffic from the expected source reaches only authorized receiver interfaces.
- Apply a consistent scoped RP mapping with verified routing to the RP.
- Configure reachable appropriate RP mapping for the required ASM group range.
- Correlate multicast route incoming interface with outgoing-interface list and group state.
- Multicast forwarding depends on both RPF incoming checks and valid outgoing interface state.
Explanation
Correct Answers
B:Traffic from the expected source reaches only authorized receiver interfaces. This is direct observable evidence for Multicast routing table incoming outgoing lists.
E:Correlate multicast route incoming interface with outgoing-interface list and group state. This is the intended implementation action for Multicast routing table incoming outgoing lists.
F:Multicast forwarding depends on both RPF incoming checks and valid outgoing interface state. It explains the action and observed outcome for Multicast routing table incoming outgoing lists.
Incorrect Answers
A:Check only the BGP session up flag and conclude multicast delivery is healthy. This would not be an appropriate Multicast routing table incoming outgoing lists decision. Missing OIF state yields no receiver traffic despite an upstream multicast feed.
C:Apply a consistent scoped RP mapping with verified routing to the RP. This belongs to Static RP mapping group range, not the specified Multicast routing table incoming outgoing lists operation. Multicast forwarding depends on both RPF incoming checks and valid outgoing interface state.
D:Configure reachable appropriate RP mapping for the required ASM group range. This belongs to PIM sparse-mode RP shared tree, not the specified Multicast routing table incoming outgoing lists operation. Multicast forwarding depends on both RPF incoming checks and valid outgoing interface state.
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.
