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Question 1000
A port used only for workstations undergoes lengthy spanning-tree transitions whenever a client reconnects. Choose THREE statements that form the design action, direct verification, and deployment safeguard. (Choose THREE.)
- Combine edge behavior with BPDU protection and verify which interfaces can attach network devices.
- All approved powered endpoints boot under full load and stay powered after one permitted PSU failure.
- Validate device power negotiation and high-priority endpoint allocations before production.
- Calculate worst-case powered-device class demand, switch power supply budget, and redundancy headroom.
- Apply a supported edge/PortFast designation only to validated endpoint-facing interfaces.
- Client ports forward promptly while bridged uplinks still receive normal loop protection.
Explanation
Correct Answers
A:Combine edge behavior with BPDU protection and verify which interfaces can attach network devices. This applies directly to the reported network-design requirement.
E:Apply a supported edge/PortFast designation only to validated endpoint-facing interfaces. This is the corrective design for the stated topology.
F:Client ports forward promptly while bridged uplinks still receive normal loop protection. This is the observable acceptance check for the change.
Incorrect Answers
B:This offered choice, “All approved powered endpoints boot under full load and stay powered after one permitted PSU failure”, addresses a separate concern. This statement relates to a different requirement: IP phones and cameras are scheduled for a new closet, but PoE budget is calculated only from the switch's total port count. It does not address the condition described here.
C:This offered choice, “Validate device power negotiation and high-priority endpoint allocations before production”, addresses a separate concern. This statement relates to a different requirement: IP phones and cameras are scheduled for a new closet, but PoE budget is calculated only from the switch's total port count. It does not address the condition described here.
D:This offered choice, “Calculate worst-case powered-device class demand, switch power supply budget, and redundancy headroom”, addresses a separate concern. This statement relates to a different requirement: IP phones and cameras are scheduled for a new closet, but PoE budget is calculated only from the switch's total port count. It does not address the condition described here.
Question 1001
The RPF interface changes after a unicast route failover, but the multicast router retains stale upstream join state. Select TWO statements that together define the best corrective design and its acceptance evidence. (Choose TWO.)
- Establish supported PIM routing with unicast RPF reachability and correct receiver membership signaling.
- Intended receivers across the routed boundary receive the source stream.
- Multicast forwarding resumes on the newly valid upstream with no persistent duplicates.
- Validate reconvergence of multicast RPF and join/prune state after unicast routing changes.
- Align SSM membership to include the desired (S,G) source/group relationship.
Explanation
Correct Answers
C:Multicast forwarding resumes on the newly valid upstream with no persistent duplicates. This is the observable acceptance check for the change.
D:Validate reconvergence of multicast RPF and join/prune state after unicast routing changes. This applies directly to the reported network-design requirement.
Incorrect Answers
A:This offered choice, “Establish supported PIM routing with unicast RPF reachability and correct receiver membership signaling”, addresses a separate concern. That answer belongs to this other scenario: A source sends multicast through one router but users join from another site and no multicast routing is configured between them. It does not establish the necessary change in this case.
B:This offered choice, “Intended receivers across the routed boundary receive the source stream”, addresses a separate concern. That answer belongs to this other scenario: A source sends multicast through one router but users join from another site and no multicast routing is configured between them. It does not establish the necessary change in this case.
E:This offered choice, “Align SSM membership to include the desired (S,G) source/group relationship”, addresses a separate concern. That answer belongs to this other scenario: A new multicast source uses group 232.1.1.1 but the client sends only (*,G) membership instead of a source-specific join. It does not establish the necessary change in this case.
Question 1002
A company accepts routes from a newly merged BGP AS without maximum-prefix limits, and the peer mistakenly sends hundreds of thousands of prefixes. Choose THREE statements that form the design action, direct verification, and deployment safeguard. (Choose THREE.)
- Observed inbound paths trend toward ISP B from representative external monitors without assuming universal control.
- Assess supported inbound traffic engineering such as scoped AS-path prepending or provider communities, recognizing remote-AS policy discretion.
- Set sensible headroom and operational alerting so normal growth does not cause unnecessary shutdown.
- The peer can exchange authorized reachability without exhausting edge memory during an erroneous advertisement surge.
- Coordinate with provider route policy and monitor diverse external vantage points.
- Apply route filtering and appropriate max-prefix safeguards proportional to approved expected routes.
Explanation
Correct Answers
C:Set sensible headroom and operational alerting so normal growth does not cause unnecessary shutdown. This applies directly to the reported network-design requirement.
D:The peer can exchange authorized reachability without exhausting edge memory during an erroneous advertisement surge. This is the observable acceptance check for the change.
F:Apply route filtering and appropriate max-prefix safeguards proportional to approved expected routes. This is the corrective design for the stated topology.
Incorrect Answers
A:This offered choice, “Observed inbound paths trend toward ISP B from representative external monitors without assuming universal control”, addresses a separate concern. This statement relates to a different requirement: A company wants most return traffic for its public prefix to enter ISP B rather than ISP A. It does not address the condition described here.
B:This offered choice, “Assess supported inbound traffic engineering such as scoped AS-path prepending or provider communities, recognizing remote-AS policy discretion”, addresses a separate concern. This statement relates to a different requirement: A company wants most return traffic for its public prefix to enter ISP B rather than ISP A. It does not address the condition described here.
E:This offered choice, “Coordinate with provider route policy and monitor diverse external vantage points”, addresses a separate concern. This statement relates to a different requirement: A company wants most return traffic for its public prefix to enter ISP B rather than ISP A. It does not address the condition described here.
Question 1003
A voice application has a 120-ms latency budget, but SD-WAN traffic follows the cheapest internet path despite BFD reporting 220-ms delay. Select TWO statements that together define the best corrective design and its acceptance evidence. (Choose TWO.)
- Choose a supported IPsec design with appropriate IKE authentication, encryption proposals and key rotation.
- Define SLA-aware application routing with measured loss, latency and jitter and intended tunnel fallback policy.
- Voice traffic uses an eligible lower-latency transport while other applications retain their separate routing requirements.
- Plan underlay/overlay MTU and MSS handling for encapsulation overhead across the WAN path.
- Approved SaaS sessions use the closer permitted breakout and remain governed by the security policy.
Explanation
Correct Answers
B:Define SLA-aware application routing with measured loss, latency and jitter and intended tunnel fallback policy. This applies directly to the reported network-design requirement.
C:Voice traffic uses an eligible lower-latency transport while other applications retain their separate routing requirements. This is the observable acceptance check for the change.
Incorrect Answers
A:That answer belongs to this other scenario: A site-to-site tunnel must protect financial payload confidentiality and integrity across the public internet. It does not establish the necessary change in this case.
D:This offered choice, “Plan underlay/overlay MTU and MSS handling for encapsulation overhead across the WAN path”, addresses a separate concern. That answer belongs to this other scenario: A branch uses IPsec overlay on broadband with 1400-byte effective MTU, but an application sends 1500-byte DF-set packets and stalls. It does not establish the necessary change in this case.
E:This offered choice, “Approved SaaS sessions use the closer permitted breakout and remain governed by the security policy”, addresses a separate concern. That answer belongs to this other scenario: A retail design directs all cloud SaaS traffic through headquarters even though local internet breakout is allowed and latency is poor. It does not establish the necessary change in this case.
Question 1004
A telemetry receiver supports gRPC but cannot decode the device's gNMI JSON_IETF path data and classifies every update as malformed. Choose THREE statements that form the design action, direct verification, and deployment safeguard. (Choose THREE.)
- Select subscription modes according to the actual leaf and device support, using periodic for counters when necessary.
- Align gNMI encoding and model path interpretation with supported YANG JSON_IETF semantics.
- Query capability/model support and document fallback sampling per platform.
- The receiver obtains the expected measurement updates for every required signal.
- Validate encoding negotiation and representative samples before broad deployment.
- Subscription updates decode into typed intended metrics and preserve their source paths.
Explanation
Correct Answers
B:Align gNMI encoding and model path interpretation with supported YANG JSON_IETF semantics. This is the corrective design for the stated topology.
E:Validate encoding negotiation and representative samples before broad deployment. This applies directly to the reported network-design requirement.
F:Subscription updates decode into typed intended metrics and preserve their source paths. This is the observable acceptance check for the change.
Incorrect Answers
A:This offered choice, “Select subscription modes according to the actual leaf and device support, using periodic for counters when necessary”, addresses a separate concern. This statement relates to a different requirement: A routing telemetry client assumes every operational counter supports on-change updates and receives no updates on one platform. It does not address the condition described here.
C:This offered choice, “Query capability/model support and document fallback sampling per platform”, addresses a separate concern. This statement relates to a different requirement: A routing telemetry client assumes every operational counter supports on-change updates and receives no updates on one platform. It does not address the condition described here.
D:This offered choice, “The receiver obtains the expected measurement updates for every required signal”, addresses a separate concern. This statement relates to a different requirement: A routing telemetry client assumes every operational counter supports on-change updates and receives no updates on one platform. It does not address the condition described here.
Question 1005
A campus topology places critical services behind one regional core switch despite redundant uplinks elsewhere. Select TWO statements that together define the best corrective design and its acceptance evidence. (Choose TWO.)
- The unintended default is absent from production campus RIBs while valid branch summaries propagate.
- A core-device failure leaves required services available through the alternate attachment.
- Apply route filtering at intercampus boundaries to accept only explicitly authorized prefixes.
- Separate service attachment across independent core fault domains and validate downstream convergence.
- Use a supported multi-chassis EtherChannel or routed-access design to make redundancy active without a spanning-tree loop.
Explanation
Correct Answers
B:A core-device failure leaves required services available through the alternate attachment. This is the observable acceptance check for the change.
D:Separate service attachment across independent core fault domains and validate downstream convergence. This applies directly to the reported network-design requirement.
Incorrect Answers
A:This offered choice, “The unintended default is absent from production campus RIBs while valid branch summaries propagate”, addresses a separate concern. That answer belongs to this other scenario: A regional core accepts all branch routes and one lab site leaks its test 0.0.0.0/0 default into the global table. It does not establish the necessary change in this case.
C:This offered choice, “Apply route filtering at intercampus boundaries to accept only explicitly authorized prefixes”, addresses a separate concern. That answer belongs to this other scenario: A regional core accepts all branch routes and one lab site leaks its test 0.0.0.0/0 default into the global table. It does not establish the necessary change in this case.
E:This offered choice, “Use a supported multi-chassis EtherChannel or routed-access design to make redundancy active without a spanning-tree loop”, addresses a separate concern. That answer belongs to this other scenario: A campus design requires both distribution uplinks active but the chosen topology uses classic STP on all Layer 2 connections. It does not establish the necessary change in this case.
Question 1006
A campus plans IPv6 addressing with one /64 shared between two routed VLAN interfaces in different buildings. Choose THREE statements that form the design action, direct verification, and deployment safeguard. (Choose THREE.)
- Reserve a contiguous per-site allocation and validate all router advertisements during cutover.
- OSPF adjacencies establish only between intended authenticated peers and survive planned key changes.
- Assign distinct /64 prefixes per routed IPv6 segment from a hierarchical site allocation.
- Stage keys and document overlap windows before activation.
- Apply compatible supported OSPF authentication with coordinated keys and rollover on both ends.
- Neighbor discovery and SLAAC operate independently on both VLANs with no on-link ambiguity.
Explanation
Correct Answers
A:Reserve a contiguous per-site allocation and validate all router advertisements during cutover. This applies directly to the reported network-design requirement.
C:Assign distinct /64 prefixes per routed IPv6 segment from a hierarchical site allocation. This is the corrective design for the stated topology.
F:Neighbor discovery and SLAAC operate independently on both VLANs with no on-link ambiguity. This is the observable acceptance check for the change.
Incorrect Answers
B:This offered choice, “OSPF adjacencies establish only between intended authenticated peers and survive planned key changes”, addresses a separate concern. This statement relates to a different requirement: A security design requires authenticating OSPF control packets on shared routed links, but only one neighbor has authentication enabled. It does not address the condition described here.
D:This offered choice, “Stage keys and document overlap windows before activation”, addresses a separate concern. This statement relates to a different requirement: A security design requires authenticating OSPF control packets on shared routed links, but only one neighbor has authentication enabled. It does not address the condition described here.
E:This offered choice, “Apply compatible supported OSPF authentication with coordinated keys and rollover on both ends”, addresses a separate concern. This statement relates to a different requirement: A security design requires authenticating OSPF control packets on shared routed links, but only one neighbor has authentication enabled. It does not address the condition described here.
Question 1007
Two access switches uplink to a distribution pair; the architecture stretches one port channel across chassis without verifying multi-chassis support. Select TWO statements that together define the best corrective design and its acceptance evidence. (Choose TWO.)
- Use a validated stack/virtual chassis/MEC design or independent routed uplinks according to supported platform capabilities.
- Trust only legitimate DHCP server/uplink paths and keep edge client ports untrusted.
- Both access links forward as designed and a chassis failure retains authorized connectivity.
- Gateway traffic survives a controlled supervisor transition within the approved outage budget.
- Align advertised costs and path policy with available bandwidth and acceptable backup behavior.
Explanation
Correct Answers
A:Use a validated stack/virtual chassis/MEC design or independent routed uplinks according to supported platform capabilities. This applies directly to the reported network-design requirement.
C:Both access links forward as designed and a chassis failure retains authorized connectivity. This is the observable acceptance check for the change.
Incorrect Answers
B:This offered choice, “Trust only legitimate DHCP server/uplink paths and keep edge client ports untrusted”, addresses a separate concern. That answer belongs to this other scenario: A routed campus uses DHCP snooping on access switches but marks every endpoint port trusted for convenience. It does not establish the necessary change in this case.
D:This offered choice, “Gateway traffic survives a controlled supervisor transition within the approved outage budget”, addresses a separate concern. That answer belongs to this other scenario: A remote campus uses two distribution switches and requires nonstop gateway access during a planned supervisor replacement. It does not establish the necessary change in this case.
E:That answer belongs to this other scenario: A distribution pair advertises the same summary at two locations, but one has a 100-Mbps backhaul and receives half of campus traffic. It does not establish the necessary change in this case.
Question 1008
A source sends multicast through one router but users join from another site and no multicast routing is configured between them. Choose THREE statements that form the design action, direct verification, and deployment safeguard. (Choose THREE.)
- Exercise both link failure and restoration while monitoring (S,G) and (*,G) entries.
- Intended receivers across the routed boundary receive the source stream.
- Establish supported PIM routing with unicast RPF reachability and correct receiver membership signaling.
- Align SSM membership to include the desired (S,G) source/group relationship.
- Multicast forwarding resumes on the newly valid upstream with no persistent duplicates.
- Confirm upstream source paths and verify PIM neighbors on every routed segment.
Explanation
Correct Answers
B:Intended receivers across the routed boundary receive the source stream. This is the observable acceptance check for the change.
C:Establish supported PIM routing with unicast RPF reachability and correct receiver membership signaling. This is the corrective design for the stated topology.
F:Confirm upstream source paths and verify PIM neighbors on every routed segment. This applies directly to the reported network-design requirement.
Incorrect Answers
A:This offered choice, “Exercise both link failure and restoration while monitoring (S,G) and (*,G) entries”, addresses a separate concern. This statement relates to a different requirement: The RPF interface changes after a unicast route failover, but the multicast router retains stale upstream join state. It does not address the condition described here.
D:This statement relates to a different requirement: A new multicast source uses group 232.1.1.1 but the client sends only (*,G) membership instead of a source-specific join. It does not address the condition described here.
E:This offered choice, “Multicast forwarding resumes on the newly valid upstream with no persistent duplicates”, addresses a separate concern. This statement relates to a different requirement: The RPF interface changes after a unicast route failover, but the multicast router retains stale upstream join state. It does not address the condition described here.
Question 1009
A single-homed retail branch can tolerate a four-hour outage but the proposal adds expensive dual-carrier fiber without a business case. Select TWO statements that together define the best corrective design and its acceptance evidence. (Choose TWO.)
- Application sessions remain stable through short intermittent primary path disturbances.
- Introduce deliberate recovery policy or dampening to prevent repeated unstable failback.
- Require physical route and carrier diversity, including demarcation and access-path audits.
- The chosen design meets the approved recovery target at a justified life-cycle cost.
- Match WAN redundancy and repair targets to measured business availability needs and budget.
Explanation
Correct Answers
D:The chosen design meets the approved recovery target at a justified life-cycle cost. This is the observable acceptance check for the change.
E:Match WAN redundancy and repair targets to measured business availability needs and budget. This applies directly to the reported network-design requirement.
Incorrect Answers
A:This offered choice, “Application sessions remain stable through short intermittent primary path disturbances”, addresses a separate concern. That answer belongs to this other scenario: A dual-carrier WAN design changes to backup but automatically switches back on every momentary primary heartbeat recovery. It does not establish the necessary change in this case.
B:This offered choice, “Introduce deliberate recovery policy or dampening to prevent repeated unstable failback”, addresses a separate concern. That answer belongs to this other scenario: A dual-carrier WAN design changes to backup but automatically switches back on every momentary primary heartbeat recovery. It does not establish the necessary change in this case.
C:This offered choice, “Require physical route and carrier diversity, including demarcation and access-path audits”, addresses a separate concern. That answer belongs to this other scenario: A bank contracts two MPLS providers but both fiber tails enter the building through the same conduit. It does not establish the necessary change in this case.
Question 1010
An IPv6 deployment uses static gateways rather than a dynamic protocol across several redundant campus links. Choose THREE statements that form the design action, direct verification, and deployment safeguard. (Choose THREE.)
- Confirm address-family features and topology scale on all participating platforms.
- Advertise only summaries that fully cover owned reachable allocations; retain required exceptions or more-specifics at redistribution boundaries.
- Remote forwarding toward the summary reaches all included owned networks and does not hijack unrelated space.
- Select a scalable IPv6-capable routing design with convergence and security matched to the enterprise topology.
- IPv6 next-hop changes recover after a tested uplink failure without manual reconfiguration.
- Validate the summarization envelope against a current prefix inventory and discard-route behavior.
Explanation
Correct Answers
A:Confirm address-family features and topology scale on all participating platforms. This applies directly to the reported network-design requirement.
D:Select a scalable IPv6-capable routing design with convergence and security matched to the enterprise topology. This is the corrective design for the stated topology.
E:IPv6 next-hop changes recover after a tested uplink failure without manual reconfiguration. This is the observable acceptance check for the change.
Incorrect Answers
B:This offered choice, “Advertise only summaries that fully cover owned reachable allocations; retain required exceptions or more-specifics at redistribution boundaries”, addresses a separate concern. This statement relates to a different requirement: An enterprise uses hundreds of IPv4 /24s and proposes a single /16 summary although several component /24s are outside its administrative control. It does not address the condition described here.
C:This offered choice, “Remote forwarding toward the summary reaches all included owned networks and does not hijack unrelated space”, addresses a separate concern. This statement relates to a different requirement: An enterprise uses hundreds of IPv4 /24s and proposes a single /16 summary although several component /24s are outside its administrative control. It does not address the condition described here.
F:This offered choice, “Validate the summarization envelope against a current prefix inventory and discard-route behavior”, addresses a separate concern. This statement relates to a different requirement: An enterprise uses hundreds of IPv4 /24s and proposes a single /16 summary although several component /24s are outside its administrative control. It does not address the condition described here.
Designing Cisco Enterprise Networks (ENSLD) (300-420) Practice Tests
