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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.
Question 351
A regional core accepts all branch routes and one lab site leaks its test 0.0.0.0/0 default into the global table. Which observed result would most directly prove the design meets the intended goal?
- Duplicate prefixes coexist in isolated tables and cross-tenant routes appear only where authorized.
- Root bridge elections and forwarding paths match the documented campus topology.
- 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
D:Apply route filtering at intercampus boundaries to accept only explicitly authorized prefixes. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: Two tenants use 10.0.0.0/8 addressing and share the same campus core but require separate routing and firewall policies. It does not verify the present outcome.
B:This observation relates to a different topology: A campus wants deterministic STP roots but all switches retain default bridge priorities. It does not verify the present outcome.
C:This observation relates to a different topology: A campus topology places critical services behind one regional core switch despite redundant uplinks elsewhere. It does not verify the present outcome.
Question 352
A WAN edge has hundreds of VPN prefixes and growing TLOC paths; an all-to-all overlay approaches its platform session capacity. Which observed result would most directly prove the design meets the intended goal?
- Large application sessions succeed with correct effective packet sizing over each approved transport.
- Only authorized multicast receivers on selected sites receive the required production feed.
- Route/session counts stay within supported platform bounds and new branches join without control-plane exhaustion.
- Authorized overlay tunnels form between intended peers without manually maintained full-mesh IKE policy.
Explanation
Correct Answer
C:Plan scalable overlay topology and path policy based on actual edge session, route and encryption resource limits. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: 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 verify the present outcome.
B:This observation relates to a different topology: A manufacturing WAN requires multicast distribution but the SD-WAN overlay has only validated unicast OMP reachability. It does not verify the present outcome.
D:This observation relates to a different topology: A network team manually builds static IPsec tunnels between every SD-WAN edge even though centralized overlay policy is available. It does not verify the present outcome.
Question 353
A hospital asks for guaranteed per-flow service across 300 branches and considers IntServ RSVP state on every core router. Which observed result would most directly prove the design meets the intended goal?
- Intended receivers across the routed boundary receive the source stream.
- The chosen design meets critical-flow service expectations without unsupportable per-flow state on core devices.
- Multicast forwarding resumes on the newly valid upstream with no persistent duplicates.
- Operators can reach device management after production routing is intentionally removed.
Explanation
Correct Answer
B:Compare IntServ reservation scalability with a DiffServ class-based design that better matches the enterprise scale. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A: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.
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 observation relates to a different topology: A core router's production data plane fails, leaving SSH reachable only through the same failed core path. It does not verify the present outcome.
Question 354
An alerting system needs immediate notice of interface administrative status changes but only polls every five minutes. Which observed result would most directly prove the design meets the intended goal?
- Schema registry entries identify the correct module namespace and revisions for each controller operation.
- Collector time series captures the brief spikes with timestamped relevant YANG measurements.
- A controlled status change reaches the collector promptly without waiting for the next periodic poll.
- The collector reads comparable interface fields from Cisco and non-Cisco devices using supported model paths.
Explanation
Correct Answer
C:Use supported on-change telemetry for the interface state leaf where device and model support it. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A: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.
B:This observation relates to a different topology: An NOC polls every router with SNMP once every ten minutes and misses 30-second interface utilization spikes. It does not verify the present outcome.
D:This offered choice, “The collector reads comparable interface fields from Cisco and non-Cisco devices using supported model paths”, addresses a separate concern. That option relates to this separate design case: A multivendor enterprise wants one consistent YANG representation for interface operational counters but each platform exposes vendor-specific native trees. It does not answer the current requirement.
Question 355
An organization needs consistent segmentation across two SD-Access fabric sites connected by a routed MPLS service. Which observed result would most directly prove the design meets the intended goal?
- Guest clients roam as designed and cannot access restricted enterprise segments.
- Both routed uplinks forward to the rest of campus and a link failure reroutes traffic without a campus STP event.
- Authorized multicast receivers obtain packets while uninvolved VNs and sites remain isolated.
- Approved intersite traffic carries the expected segmentation context without undesired leakage.
Explanation
Correct Answer
D:Evaluate a supported SDA transit that preserves virtual network and SGT policy semantics between sites. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A fabric site needs a guest wireless SSID without extending the guest Layer 2 domain across the whole enterprise. It does not verify the present outcome.
B:This observation relates to a different topology: A routed-access campus needs equal-cost forwarding to two distribution routers while keeping each VLAN local to one wiring closet. It does not verify the present outcome.
C:This observation relates to a different topology: A financial application needs multicast delivery across SDA sites, but all validation has covered unicast endpoint maps only. It does not verify the present outcome.
Question 356
A dual-stack enterprise BGP peer exchanges IPv4 NLRI but no IPv6 routes despite IPv6 addressing on the transport. Which observed result would most directly prove the design meets the intended goal?
- The intended exit preference propagates across internal BGP speakers.
- Neighbor discovery and SLAAC operate independently on both VLANs with no on-link ambiguity.
- Authorized IPv4 partner sessions reach the selected IPv6 service through the documented translation path.
- IPv6 NLRI appears only in the authorized address-family tables with validated next-hop reachability.
Explanation
Correct Answer
D:Activate and filter the correct IPv6 unicast MP-BGP address family on the intended peers. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A BGP operator attempts to influence routes within one AS by changing the weight attribute only on one edge router. It does not verify the present outcome.
B:This observation relates to a different topology: A campus plans IPv6 addressing with one /64 shared between two routed VLAN interfaces in different buildings. It does not verify the present outcome.
C:This observation relates to a different topology: A company wants to expose IPv6 resources to a partner with IPv4-only routing and assumes dual stack at headquarters solves the partner boundary. It does not verify the present outcome.
Question 357
A many-to-many trading network has multiple multicast senders and a scalable shared-tree forwarding requirement. Which observed result would most directly prove the design meets the intended goal?
- Intended receivers across the routed boundary receive the source stream.
- Receiver forwarding follows the intended tree state after source discovery and any supported SPT transition.
- Guest routing tables contain no unauthorized management loopback routes.
- Multiple authorized sources reach receiver sets through the designed bidirectional shared tree.
Explanation
Correct Answer
D:Evaluate bidirectional PIM for appropriate many-to-many traffic patterns and RP placement. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A: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.
B:This observation relates to a different topology: A team expects multicast traffic to traverse a shared tree forever even though its design requests shortest-path switching. It does not verify the present outcome.
C:This observation relates to a different topology: A campus firewall isolates management VRFs but its shared-services route leaking exports all loopbacks to the guest VRF. It does not verify the present outcome.
Question 358
Two industrial sites require transparent delivery of a small set of Ethernet services and reject routing between their private LANs. Which observed result would most directly prove the design meets the intended goal?
- Each branch exchanges only authorized VPN routes while the provider backbone transports traffic without L2 extension.
- The edge establishes intended tunnels over both transports and applications use their approved paths.
- Approved Ethernet frames reach the remote service endpoint while unrelated VLANs remain excluded.
- Expected tagged traffic traverses the authorized EVC and unrelated tags are isolated.
Explanation
Correct Answer
C:Evaluate an appropriately isolated L2VPN or pseudowire with defined loop, bandwidth and MTU constraints. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A customer needs private route separation for 12 branches over a shared provider backbone, not a single Ethernet broadcast domain. It does not verify the present outcome.
B:This observation relates to a different topology: A small branch must use both Internet and private MPLS, and engineers assume the two underlays cannot coexist on one SD-WAN edge. It does not verify the present outcome.
D:This observation relates to a different topology: Two enterprise buildings use separate Metro Ethernet UNI ports, yet their operators assume the provider will preserve any configured customer VLAN ID. It does not verify the present outcome.
Question 359
A sensitive engineering VLAN needs to deny lateral guest traffic within one switched segment; existing router ACLs do not inspect intra-VLAN frames. Which observed result would most directly prove the design meets the intended goal?
- Test traffic between unauthorized hosts in the VLAN is denied while approved flows continue.
- Guest clients roam as designed and cannot access restricted enterprise segments.
- Switches participate in the expected common region and root placement is consistent per instance.
- Both routed uplinks forward to the rest of campus and a link failure reroutes traffic without a campus STP event.
Explanation
Correct Answer
A:Evaluate an appropriate VLAN access map or supported intra-segment security mechanism. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
B:This observation relates to a different topology: A fabric site needs a guest wireless SSID without extending the guest Layer 2 domain across the whole enterprise. It does not verify the present outcome.
C:This observation relates to a different topology: A new MST campus region accidentally has a different VLAN-to-instance mapping on one distribution switch. It does not verify the present outcome.
D:This observation relates to a different topology: A routed-access campus needs equal-cost forwarding to two distribution routers while keeping each VLAN local to one wiring closet. It does not verify the present outcome.
Question 360
A branch engineer redistributes a static default route into EIGRP and advertises it to every site, overriding the intended hub defaults. Which observed result would most directly prove the design meets the intended goal?
- Only intended branches learn the approved default source and backup behavior.
- Branch routers no longer send packets for the retired /24 into a blackhole created by the former summary.
- Hubs avoid querying through the branch as a transit path and branch-local prefixes remain visible.
- Branch routes remain reachable through the surviving aggregation router after failure.
Explanation
Correct Answer
A:Filter or scope external default advertisements to the authorized EIGRP distribution boundaries. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
B:This observation relates to a different topology: A campus advertises a /18 summary into the WAN but has no route for one constituent /24 after a building is decommissioned. It does not verify the present outcome.
C:This observation relates to a different topology: A branch EIGRP router advertises remote routes back into its hub and occasionally becomes a transit path between hubs. It does not verify the present outcome.
D:This observation relates to a different topology: An EIGRP deployment relies on a single aggregation router and an outage cuts off all downstream branches. It does not verify the present outcome.
Designing Cisco Enterprise Networks (ENSLD) (300-420) Practice Tests
