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Question 340
A port used only for workstations undergoes lengthy spanning-tree transitions whenever a client reconnects. Which observed result would most directly prove the design meets the intended goal?
- All approved powered endpoints boot under full load and stay powered after one permitted PSU failure.
- A moved endpoint retains its intended policy and access to only approved destinations.
- Client ports forward promptly while bridged uplinks still receive normal loop protection.
- The rogue bridge cannot become campus root and protected access interfaces enter their intended security state.
Explanation
Correct Answer
C:Apply a supported edge/PortFast designation only to validated endpoint-facing interfaces. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: 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 verify the present outcome.
B:This observation relates to a different topology: Users roam between wired fabric edge switches but their identity assignments change with switch port, breaking microsegmentation. It does not verify the present outcome.
D:This observation relates to a different topology: An attacker plugs an unmanaged switch into a lobby edge port and advertises superior STP BPDUs, changing the root topology. It does not verify the present outcome.
Question 341
The RPF interface changes after a unicast route failover, but the multicast router retains stale upstream join state. Which observed result would most directly prove the design meets the intended goal?
- The receiver sends a source-specific join and obtains only the authorized stream.
- Multicast forwarding resumes on the newly valid upstream with no persistent duplicates.
- Intended receivers across the routed boundary receive the source stream.
- Packets arriving on incorrect RPF interfaces are rejected and legitimate receiver traffic passes.
Explanation
Correct Answer
B:Validate reconvergence of multicast RPF and join/prune state after unicast routing changes. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: 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 verify the present outcome.
C:This observation relates to a different topology: A source sends multicast through one router but users join from another site and no multicast routing is configured between them. It does not verify the present outcome.
D:This observation relates to a different topology: A multicast source is reachable through an interface other than the one receiving the packet, but the router still forwards it to all receivers. It does not verify the present outcome.
Question 342
A company accepts routes from a newly merged BGP AS without maximum-prefix limits, and the peer mistakenly sends hundreds of thousands of prefixes. Which observed result would most directly prove the design meets the intended goal?
- The optimal successor forwards normally and eligible backup takes over without a network-wide query where feasible.
- Allowed external routes appear without reentering their origin routing domain on an alternate border.
- Observed inbound paths trend toward ISP B from representative external monitors without assuming universal control.
- The peer can exchange authorized reachability without exhausting edge memory during an erroneous advertisement surge.
Explanation
Correct Answer
D:Apply route filtering and appropriate max-prefix safeguards proportional to approved expected routes. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A router receives two EIGRP routes for a prefix with different metrics and the design team wants deterministic failover. It does not verify the present outcome.
B:This observation relates to a different topology: IS-IS adjacencies form between distribution switches, but all internal prefixes are redistributed from OSPF without loop prevention. It does not verify the present outcome.
C:This observation relates to a different topology: A company wants most return traffic for its public prefix to enter ISP B rather than ISP A. It does not verify the present outcome.
Question 343
A voice application has a 120-ms latency budget, but SD-WAN traffic follows the cheapest internet path despite BFD reporting 220-ms delay. Which observed result would most directly prove the design meets the intended goal?
- Approved SaaS sessions use the closer permitted breakout and remain governed by the security policy.
- Voice traffic uses an eligible lower-latency transport while other applications retain their separate routing requirements.
- Protected traffic crosses an established security association and is unreadable on the public underlay.
- Selected tunnels meet the approved performance envelope during representative conference traffic.
Explanation
Correct Answer
B:Define SLA-aware application routing with measured loss, latency and jitter and intended tunnel fallback policy. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A retail design directs all cloud SaaS traffic through headquarters even though local internet breakout is allowed and latency is poor. It does not verify the present outcome.
C:This observation relates to a different topology: A site-to-site tunnel must protect financial payload confidentiality and integrity across the public internet. It does not verify the present outcome.
D:This observation relates to a different topology: A video conference SD-WAN policy accepts tunnels with 1% packet loss but ignores sustained jitter above application tolerance. It does not verify the present outcome.
Question 344
A telemetry receiver supports gRPC but cannot decode the device's gNMI JSON_IETF path data and classifies every update as malformed. Which observed result would most directly prove the design meets the intended goal?
- The collector receives actionable measurements without saturating management transport or device CPU.
- Schema registry entries identify the correct module namespace and revisions for each controller operation.
- Subscription updates decode into typed intended metrics and preserve their source paths.
- The receiver obtains the expected measurement updates for every required signal.
Explanation
Correct Answer
C:Align gNMI encoding and model path interpretation with supported YANG JSON_IETF semantics. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A fleet telemetry design streams all available operational leaves every second over a constrained management link. It does not verify the present outcome.
B:This observation relates to a different topology: A standards group needs an interoperable interface model but mistakenly calls every IETF YANG module an OpenConfig model. It does not verify the present outcome.
D:This observation relates to a different topology: A routing telemetry client assumes every operational counter supports on-change updates and receives no updates on one platform. It does not verify the present outcome.
Question 345
A campus topology places critical services behind one regional core switch despite redundant uplinks elsewhere. Which observed result would most directly prove the design meets the intended goal?
- Permitted uplinks forward under normal operation and converge cleanly on individual link loss.
- Only the approved number of endpoint identities can use the port while rogue downstream devices are blocked.
- A core-device failure leaves required services available through the alternate attachment.
- The unintended default is absent from production campus RIBs while valid branch summaries propagate.
Explanation
Correct Answer
C:Separate service attachment across independent core fault domains and validate downstream convergence. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: Multiple access switches connect to one distribution block through independent Layer 2 uplinks with a blocked redundant path. It does not verify the present outcome.
B:This observation relates to a different topology: A guest workstation port can learn hundreds of source MAC addresses because an unmanaged mini-switch is connected behind it. It does not verify the present outcome.
D:This observation relates to a different topology: 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 verify the present outcome.
Question 346
A campus plans IPv6 addressing with one /64 shared between two routed VLAN interfaces in different buildings. Which observed result would most directly prove the design meets the intended goal?
- Clients reach the headquarters destination over the routed path using the approved office prefix.
- IPv6 NLRI appears only in the authorized address-family tables with validated next-hop reachability.
- OSPF adjacencies establish only between intended authenticated peers and survive planned key changes.
- Neighbor discovery and SLAAC operate independently on both VLANs with no on-link ambiguity.
Explanation
Correct Answer
D:Assign distinct /64 prefixes per routed IPv6 segment from a hierarchical site allocation. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A remote office assigns clients addresses from 169.254.0.0/16 and expects them to be reachable through a routed WAN. It does not verify the present outcome.
B:This observation relates to a different topology: A dual-stack enterprise BGP peer exchanges IPv4 NLRI but no IPv6 routes despite IPv6 addressing on the transport. It does not verify the present outcome.
C:This observation relates to a different topology: A security design requires authenticating OSPF control packets on shared routed links, but only one neighbor has authentication enabled. It does not verify the present outcome.
Question 347
Two access switches uplink to a distribution pair; the architecture stretches one port channel across chassis without verifying multi-chassis support. Which observed result would most directly prove the design meets the intended goal?
- Normal flow distribution avoids congesting the slow backhaul and failover still reaches the destination.
- Both access links forward as designed and a chassis failure retains authorized connectivity.
- Permitted uplinks forward under normal operation and converge cleanly on individual link loss.
- Gateway traffic survives a controlled supervisor transition within the approved outage budget.
Explanation
Correct Answer
B:Use a validated stack/virtual chassis/MEC design or independent routed uplinks according to supported platform capabilities. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: 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 verify the present outcome.
C:This observation relates to a different topology: Multiple access switches connect to one distribution block through independent Layer 2 uplinks with a blocked redundant path. It does not verify the present outcome.
D:This observation relates to a different topology: A remote campus uses two distribution switches and requires nonstop gateway access during a planned supervisor replacement. It does not verify the present outcome.
Question 348
A source sends multicast through one router but users join from another site and no multicast routing is configured between them. Which observed result would most directly prove the design meets the intended goal?
- Intended receivers across the routed boundary receive the source stream.
- Packets arriving on incorrect RPF interfaces are rejected and legitimate receiver traffic passes.
- Multicast forwarding resumes on the newly valid upstream with no persistent duplicates.
- Voice latency and packet loss stay within the approved limit during controlled WAN congestion.
Explanation
Correct Answer
A:Establish supported PIM routing with unicast RPF reachability and correct receiver membership signaling. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
B:This observation relates to a different topology: A multicast source is reachable through an interface other than the one receiving the packet, but the router still forwards it to all receivers. It does not verify the present outcome.
C:This observation relates to a different topology: The RPF interface changes after a unicast route failover, but the multicast router retains stale upstream join state. It does not verify the present outcome.
D:This offered choice, “Voice latency and packet loss stay within the approved limit during controlled WAN congestion”, addresses a separate concern. That option relates to this separate design case: A regional WAN prioritizes voice using a DiffServ marking but provides no scheduler preference on its congested egress link. It does not answer the current requirement.
Question 349
A single-homed retail branch can tolerate a four-hour outage but the proposal adds expensive dual-carrier fiber without a business case. Which observed result would most directly prove the design meets the intended goal?
- A controlled failure of either carrier access route leaves required service operational on the independent path.
- The required VPN tunnels and critical services establish over cellular during a failure exercise.
- Application sessions remain stable through short intermittent primary path disturbances.
- The chosen design meets the approved recovery target at a justified life-cycle cost.
Explanation
Correct Answer
D:Match WAN redundancy and repair targets to measured business availability needs and budget. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A bank contracts two MPLS providers but both fiber tails enter the building through the same conduit. It does not verify the present outcome.
B:This observation relates to a different topology: Backup 5G is installed at a factory but its data plan and APN firewall rules block VPN establishment after primary fiber failure. It does not verify the present outcome.
C:This observation relates to a different topology: A dual-carrier WAN design changes to backup but automatically switches back on every momentary primary heartbeat recovery. It does not verify the present outcome.
Question 350
An IPv6 deployment uses static gateways rather than a dynamic protocol across several redundant campus links. Which observed result would most directly prove the design meets the intended goal?
- Observed inbound paths trend toward ISP B from representative external monitors without assuming universal control.
- All advertised LAN /64s are distinct and can be summarized within the delegated /48 where topology permits.
- IPv6 next-hop changes recover after a tested uplink failure without manual reconfiguration.
- Remote forwarding toward the summary reaches all included owned networks and does not hijack unrelated space.
Explanation
Correct Answer
C:Select a scalable IPv6-capable routing design with convergence and security matched to the enterprise topology. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A company wants most return traffic for its public prefix to enter ISP B rather than ISP A. It does not verify the present outcome.
B:This observation would validate a different case: A provider delegation contains 2001:db8:4200::/48 and the design requires 256 independent /64 LANs across 16 branches. It does not establish the target outcome for this topology.
D:This observation relates to a different topology: 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 verify the present outcome.
Designing Cisco Enterprise Networks (ENSLD) (300-420) Practice Tests
