100% Latest & Updated Cisco 300-420 Practice Test Questions, Exam Dumps & Verified Answers!
30 Days Free Updates, Instant Download!
Question 830
A remote office assigns clients addresses from 169.254.0.0/16 and expects them to be reachable through a routed WAN. The chosen correction is: Use a legitimately allocated private or global prefix at the remote site and reserve IPv4 link-local for local-only communication. Which additional predeployment check is most relevant?
- Audit DHCP and static address assignments prior to moving the site to its routed block.
- Confirm path diversity at reflectors and ensure no unintended loops or excess table growth.
- Identify appropriate ABR locations and verify that existing prefix aggregation is topologically sound.
- Reserve a contiguous per-site allocation and validate all router advertisements during cutover.
Explanation
Correct Answer
A:Audit DHCP and static address assignments prior to moving the site to its routed block. This protects the intended outcome: Clients reach the headquarters destination over the routed path using the approved office prefix.
Incorrect Answers
B:That precaution belongs to another scenario: An iBGP route reflector sees several candidate routes to the same destination but advertises only its best path to clients. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: An OSPF deployment puts all 600 remote access switches into area 0 and floods changes to every site. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: A campus plans IPv6 addressing with one /64 shared between two routed VLAN interfaces in different buildings. It is not the primary safeguard for this rollout.
Question 831
A branch aggregation point has both IS-IS and OSPF neighbors with multiple equal-cost exits; traffic unexpectedly hairpins through a data center. The chosen correction is: Simplify path preference at domain boundaries and choose intended transit points based on actual traffic flows. Which additional predeployment check is most relevant?
- Validate hash entropy and elephant-flow effects before sizing links.
- Define origin-tag conventions and verify both redistribution devices during failover.
- Confirm multicast, wireless, and mobility requirements before retiring stretched VLANs.
- Simulate failure and steady-state route selection before changing handoff metrics.
Explanation
Correct Answer
D:Simulate failure and steady-state route selection before changing handoff metrics. This protects the intended outcome: Intercampus traffic follows authorized shortest feasible paths rather than unwanted data-center detours.
Incorrect Answers
A:That precaution belongs to another scenario: A multicampus network has two equal-cost paths but the design assumes packets always alternate evenly across every individual packet. It is not the primary safeguard for this rollout.
B:That precaution belongs to another scenario: Two intercampus routers redistribute OSPF and EIGRP in both directions, making route origin hard to track. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A routed-access campus needs equal-cost forwarding to two distribution routers while keeping each VLAN local to one wiring closet. It is not the primary safeguard for this rollout.
Question 832
Two hospitals need their existing Ethernet VLANs extended across a provider circuit but their engineers incorrectly request a routed L3VPN. The chosen correction is: Evaluate a provider Layer 2 VPN or Ethernet virtual circuit with explicit loop, MTU and broadcast containment design. Which additional predeployment check is most relevant?
- Validate the true need for L2 extension and the risk of spanning a failure domain between facilities.
- Add separate encryption where the threat model requires it and verify provider SLA.
- Verify customer route limits, route-target import/export and CE-PE failover.
- Verify UNI/ENNI behavior and available MTU across the provider boundary.
Explanation
Correct Answer
A:Validate the true need for L2 extension and the risk of spanning a failure domain between facilities. This protects the intended outcome: The approved VLAN service operates end to end without leaking unrelated hospital segments.
Incorrect Answers
B:That precaution belongs to another scenario: A regional healthcare group wants routed site separation within a provider-managed private WAN without building its own full mesh of tunnels. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A customer needs private route separation for 12 branches over a shared provider backbone, not a single Ethernet broadcast domain. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: Two enterprise buildings use separate Metro Ethernet UNI ports, yet their operators assume the provider will preserve any configured customer VLAN ID. It is not the primary safeguard for this rollout.
Question 833
A support dashboard needs regular CPU and interface-rate samples even when values remain unchanged. The chosen correction is: Use a periodic telemetry subscription at a measured cadence suitable for trending and capacity planning. Which additional predeployment check is most relevant?
- Validate module namespace and device-supported YANG library before generating requests.
- Validate time synchronization and retention windows at both device and collector.
- Tune frequency to the collector capacity and device resource budget.
- Confirm the chosen leaf supports on-change and implement appropriate event deduplication.
Explanation
Correct Answer
C:Tune frequency to the collector capacity and device resource budget. This protects the intended outcome: The receiver continues receiving timestamped samples during steady-state operation.
Incorrect Answers
A:That precaution belongs to another scenario: A standards group needs an interoperable interface model but mistakenly calls every IETF YANG module an OpenConfig model. It is not the primary safeguard for this rollout.
B:That precaution belongs to another scenario: A security operations service needs authoritative interface state changes, not a dashboard that replays stale telemetry after collector failure. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: An alerting system needs immediate notice of interface administrative status changes but only polls every five minutes. It is not the primary safeguard for this rollout.
Question 834
A 20-Mbps backup link replaces a 200-Mbps primary WAN but the shaper keeps its 200-Mbps limit after failover. The chosen correction is: Use link-aware QoS policy to update shaping and class allocations for the reduced-capacity backup transport. Which additional predeployment check is most relevant?
- Test the OOB path and escalation workflow periodically.
- Verify backup throughput and overhead during real failover testing.
- Audit markings at endpoint, access and WAN boundaries before rewriting application policies.
- Include control, default, and scavenger classes when totaling reserved bandwidth.
Explanation
Correct Answer
B:Verify backup throughput and overhead during real failover testing. This protects the intended outcome: Backup traffic stays within the 20-Mbps service rate and critical classes remain usable.
Incorrect Answers
A:That precaution belongs to another scenario: Network management of a branch uses a VPN over its sole primary WAN, and the organization reports no way to diagnose a provider outage. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A campus uses DSCP EF for voice signaling, voice media, and backup traffic, causing priority queue overload. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: A switch QoS scheduler guarantees 30% to backup traffic and 80% to voice under full congestion, exceeding possible link capacity. It is not the primary safeguard for this rollout.
Question 835
Multiple campus cores are connected in a full mesh, creating expensive adjacency and troubleshooting overhead. The chosen correction is: Use a topology appropriate to business resilience requirements, such as a structured regional core with redundant distribution paths. Which additional predeployment check is most relevant?
- Check fault-domain separation and latency constraints before removing redundant paths.
- Test the smallest interswitch path and supported MTU settings before fabric activation.
- Confirm route leaking and firewall context capacity before moving the border.
- Verify platform multi-chassis capability and fate sharing before bundling cross-chassis links.
Explanation
Correct Answer
A:Check fault-domain separation and latency constraints before removing redundant paths. This protects the intended outcome: A single link failure preserves required site connectivity without unnecessary adjacency proliferation.
Incorrect Answers
B:That precaution belongs to another scenario: Fabric edge nodes encapsulate packets, but the underlay path MTU is too small for added VXLAN overhead. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A campus has a fabric border but its external firewall cannot distinguish multiple endpoint VNs leaving the fabric. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: Multiple access switches connect to one distribution block through independent Layer 2 uplinks with a blocked redundant path. It is not the primary safeguard for this rollout.
Question 836
A branch OSPF design selects a totally stubby area but an application requires type-3 interarea routes rather than only the default. The chosen correction is: Choose the appropriate stub-area variant or redesign to preserve required interarea summaries. Which additional predeployment check is most relevant?
- Audit reachable service prefixes and router roles before enabling area restrictions.
- Validate default-route behavior and NSSA translation roles during staged cutover.
- Prefer durable backbone topology repair over making virtual links a permanent substitute for good design.
- Diagram route origins and inspect tags at each redistribution handoff.
Explanation
Correct Answer
A:Audit reachable service prefixes and router roles before enabling area restrictions. This protects the intended outcome: The branch receives the intended interarea destinations and no unwanted external LSAs.
Incorrect Answers
B:That precaution belongs to another scenario: A remote branch uses an OSPF stub area but a design change introduces an ASBR that must redistribute external routes within it. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A campus OSPF area 0 is split into disconnected islands connected only by another area; route distribution is unstable. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: Branch A and B redistribute external BGP into OSPF, then advertise resulting routes back into BGP at the opposite edge. It is not the primary safeguard for this rollout.
Question 837
A city campus needs a 10-Gbps local metro interconnect with SLA and carrier demarcation, but the proposed design assumes standard broadband internet guarantees. The chosen correction is: Evaluate a Metro Ethernet service with committed bandwidth, fault demarcation and suitable Ethernet handoff. Which additional predeployment check is most relevant?
- Validate SIM/APN addressing and tunnel establishment from each cellular provider.
- Validate carrier availability, diversity and any tagged VLAN handoff requirements.
- Measure real failover link capacity and decide which applications must be deprioritized.
- Confirm identity, DNS, filtering and branch service-chaining requirements before activating breakout.
Explanation
Correct Answer
B:Validate carrier availability, diversity and any tagged VLAN handoff requirements. This protects the intended outcome: Measured throughput and failover meet the contractual envelope across the metro sites.
Incorrect Answers
A:That precaution belongs to another scenario: An industrial site uses 4G LTE as primary WAN, and its routing team assumes public inbound addresses remain reachable through carrier-grade NAT. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A branch has broadband backup with no QoS controls and a voice service drops under failover saturation. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: A retail design directs all cloud SaaS traffic through headquarters even though local internet breakout is allowed and latency is poor. It is not the primary safeguard for this rollout.
Question 838
A branch QoS policy matches all TCP 443 traffic as video, including large software downloads. The chosen correction is: Use validated application classification or more precise traffic identity instead of assuming TCP port 443 defines one service. Which additional predeployment check is most relevant?
- Verify classification with application telemetry and manage encrypted-traffic visibility constraints.
- Size the priority class and verify congestion behavior with realistic mixes.
- Prevent uncontrolled high-rate management flows from abusing the protected class.
- Document permitted DSCP translations and validate the provider's supported class values.
Explanation
Correct Answer
A:Verify classification with application telemetry and manage encrypted-traffic visibility constraints. This protects the intended outcome: Only the intended interactive application receives real-time class treatment during a test.
Incorrect Answers
B:That precaution belongs to another scenario: Video and voice both use one strict-priority queue, causing voice jitter when video surges. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A campus QoS policy gives low priority to routing keepalives and network monitoring, and routing adjacencies flap during congestion. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: Two sites use different DSCP mappings for the same video stream and one class is downgraded at the carrier boundary. It is not the primary safeguard for this rollout.
Question 839
Two campus distribution routers each have a single power feed from the same rack PDU, yet the architecture counts them as separate fault domains. The chosen correction is: Provide independent power infrastructure for each redundant network node and validate dual-path resilience. Which additional predeployment check is most relevant?
- Confirm multicast, wireless, and mobility requirements before retiring stretched VLANs.
- Audit rack power and upstream physical paths before accepting a two-device availability claim.
- Validate software and licensing support, peer links, and split-brain safeguards before deployment.
- Validate applications requiring nonroutable discovery before enabling targeted relays.
Explanation
Correct Answer
B:Audit rack power and upstream physical paths before accepting a two-device availability claim. This protects the intended outcome: Loss of either PDU leaves the campus default gateway and upstream traffic operating.
Incorrect Answers
A:That precaution belongs to another scenario: A routed-access campus needs equal-cost forwarding to two distribution routers while keeping each VLAN local to one wiring closet. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: Two access switches uplink to a distribution pair; the architecture stretches one port channel across chassis without verifying multi-chassis support. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: A campus access layer spans large broadcast domains for print discovery despite an architecture target of small local VLANs. It is not the primary safeguard for this rollout.
Question 840
A branch EIGRP router advertises remote routes back into its hub and occasionally becomes a transit path between hubs. The chosen correction is: Configure an appropriate EIGRP stub design on the branch while allowing its locally connected routes to reach the hubs. Which additional predeployment check is most relevant?
- Validate advertised stub route classes and redundancy if the branch has multiple uplinks.
- Use topology-table evidence and controlled link-failure testing to validate backup eligibility.
- Confirm path diversity at reflectors and ensure no unintended loops or excess table growth.
- Review route reachability and summary boundaries before introducing stub behavior.
Explanation
Correct Answer
A:Validate advertised stub route classes and redundancy if the branch has multiple uplinks. This protects the intended outcome: Hubs avoid querying through the branch as a transit path and branch-local prefixes remain visible.
Incorrect Answers
B:That precaution belongs to another scenario: A router receives two EIGRP routes for a prefix with different metrics and the design team wants deterministic failover. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: An iBGP route reflector sees several candidate routes to the same destination but advertises only its best path to clients. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: An EIGRP core has routes stuck active after one WAN path fails and queries spread into many remote sites. It is not the primary safeguard for this rollout.
Designing Cisco Enterprise Networks (ENSLD) (300-420) Practice Tests
