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Question 750
A multicampus network has two equal-cost paths but the design assumes packets always alternate evenly across every individual packet. The chosen correction is: Plan ECMP based on actual per-flow hashing and application sensitivity rather than guaranteed per-packet load balance. Which additional predeployment check is most relevant?
- Verify map resolution and fabric edge RLOC reachability independently.
- Test the full supported transit profile rather than relying on basic IP ping success.
- Simulate failure and steady-state route selection before changing handoff metrics.
- Validate hash entropy and elephant-flow effects before sizing links.
Explanation
Correct Answer
D:Validate hash entropy and elephant-flow effects before sizing links. This protects the intended outcome: Representative flows distribute across eligible next hops while a single ordered flow remains stable.
Incorrect Answers
A:That precaution belongs to another scenario: An SD-Access architect assumes the fabric's LISP control plane transports all user packets like a data-plane tunnel. It is not the primary safeguard for this rollout.
B:That precaution belongs to another scenario: A design extends SDA fabric across buildings on a WAN with 1500-byte MTU and assumes local campus performance will continue unchanged. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A branch aggregation point has both IS-IS and OSPF neighbors with multiple equal-cost exits; traffic unexpectedly hairpins through a data center. It is not the primary safeguard for this rollout.
Question 751
During a branch expansion, the address plan fills every usable subnet identifier and leaves no room for point-to-point links or future aggregation. The chosen correction is: Reserve infrastructure and growth ranges separately within a hierarchical IPv4 and IPv6 allocation plan. Which additional predeployment check is most relevant?
- Inventory application dependencies and DNS behavior before choosing the translation mechanism.
- Model preferred and backup routes with tags and test failure behavior before enabling both ASBRs.
- Verify upstream fate sharing and convergence on a controlled aggregation outage.
- Document forecast host counts, prefix sizes, and growth margins before issuing new allocations.
Explanation
Correct Answer
D:Document forecast host counts, prefix sizes, and growth margins before issuing new allocations. This protects the intended outcome: New links and sites receive nonoverlapping prefixes without renumbering established regional summaries.
Incorrect Answers
A:That precaution belongs to another scenario: A new IPv6-only client subnet must access a legacy IPv4-only web endpoint through an enterprise gateway. It is not the primary safeguard for this rollout.
B:That precaution belongs to another scenario: An OSPF redistribution boundary introduces the same connected subnet from two ASBRs, resulting in inconsistent egress selection. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: An EIGRP deployment relies on a single aggregation router and an outage cuts off all downstream branches. It is not the primary safeguard for this rollout.
Question 752
A hospital uses one leased WAN circuit for critical access, but its architecture report calls the site highly available because it has two LAN switches. The chosen correction is: Add genuinely diverse WAN transport and edge device options consistent with the recovery requirement. Which additional predeployment check is most relevant?
- Verify per-VPN OMP routes, firewall rules and destination reachability during staging.
- Test management and control outages independently with application probes.
- Inspect provider conduit, POP and edge-router fate sharing before crediting path diversity.
- Record SLA impact and safe return criteria before enabling automatic restoration.
Explanation
Correct Answer
C:Inspect provider conduit, POP and edge-router fate sharing before crediting path diversity. This protects the intended outcome: The branch reaches core services after failure of the original carrier handoff.
Incorrect Answers
A:That precaution belongs to another scenario: An SD-WAN fabric routes guest traffic into the production VPN because a new edge reused the corporate service VPN identifier. It is not the primary safeguard for this rollout.
B:That precaution belongs to another scenario: A multisite SD-WAN deployment uses one manager for configuration and assumes manager reachability is necessary for every packet of user data. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: A dual-carrier WAN design changes to backup but automatically switches back on every momentary primary heartbeat recovery. It is not the primary safeguard for this rollout.
Question 753
A fleet telemetry design streams all available operational leaves every second over a constrained management link. The chosen correction is: Subscribe only to required model paths with appropriate update mode and cadence. Which additional predeployment check is most relevant?
- Query capability/model support and document fallback sampling per platform.
- Baseline byte rates, memory and packet loss before enabling subscriptions on all devices.
- Measure aggregation accuracy after downsampling before changing alert thresholds.
- Calculate device and collector resource impact for chosen telemetry frequency.
Explanation
Correct Answer
B:Baseline byte rates, memory and packet loss before enabling subscriptions on all devices. This protects the intended outcome: The collector receives actionable measurements without saturating management transport or device CPU.
Incorrect Answers
A:That precaution belongs to another scenario: A routing telemetry client assumes every operational counter supports on-change updates and receives no updates on one platform. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A global WAN telemetry system publishes a complete 10,000-interface snapshot every 100 ms although the target is only five-minute capacity planning. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: An NOC polls every router with SNMP once every ten minutes and misses 30-second interface utilization spikes. It is not the primary safeguard for this rollout.
Question 754
A core router's production data plane fails, leaving SSH reachable only through the same failed core path. The chosen correction is: Provide an independently reachable out-of-band management network and approved emergency access process. Which additional predeployment check is most relevant?
- Validate source reachability and PIM state before changing multicast policy.
- Secure the OOB path and verify its separate power and access transport.
- Test break-glass use and preserve security event audit after connectivity returns.
- Quantify simultaneous flows and confirm end-to-end provider QoS contracts before selecting a model.
Explanation
Correct Answer
B:Secure the OOB path and verify its separate power and access transport. This protects the intended outcome: Operators can reach device management after production routing is intentionally removed.
Incorrect Answers
A:That precaution belongs to another scenario: 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 is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A campus has out-of-band console servers but all consoles depend on the production AAA server reachable only over the failed production network. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: A hospital asks for guaranteed per-flow service across 300 branches and considers IntServ RSVP state on every core router. It is not the primary safeguard for this rollout.
Question 755
A campus border is configured with two equal-cost external BGP paths but only one is installed for traffic forwarding. The chosen correction is: Enable and validate supported BGP multipath features subject to equal-path eligibility requirements. Which additional predeployment check is most relevant?
- Diagram route origins and inspect tags at each redistribution handoff.
- Validate default-route behavior and NSSA translation roles during staged cutover.
- Verify path attributes, platform multipath limits, and asymmetric application requirements.
- Inspect feasible distance and reported distance for candidate successors before rollout.
Explanation
Correct Answer
C:Verify path attributes, platform multipath limits, and asymmetric application requirements. This protects the intended outcome: Both eligible next hops appear in the forwarding table and share representative flows.
Incorrect Answers
A: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.
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.
D:That precaution belongs to another scenario: A designer proposes unequal-cost EIGRP load sharing for two paths whose topology prevents one path from meeting the feasibility condition. It is not the primary safeguard for this rollout.
Question 756
A new MST campus region accidentally has a different VLAN-to-instance mapping on one distribution switch. The chosen correction is: Align MST region name, revision, and VLAN-to-instance mapping on intended peers. Which additional predeployment check is most relevant?
- Document the region digest and validate VLAN ownership on every participating device.
- Verify VLAN membership, upstream reachability and failure ownership before activating the virtual address.
- Confirm multicast, wireless, and mobility requirements before retiring stretched VLANs.
- Map chassis, power, supervisors, and uplink fate sharing before approving the design.
Explanation
Correct Answer
A:Document the region digest and validate VLAN ownership on every participating device. This protects the intended outcome: Switches participate in the expected common region and root placement is consistent per instance.
Incorrect Answers
B:That precaution belongs to another scenario: A building has two independent distribution switches but hosts use the physical IP of one switch as their default gateway. 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.
D:That precaution belongs to another scenario: A virtualized distribution pair uses one logical control plane and engineers assume it offers separate failure domains like two chassis in different buildings. It is not the primary safeguard for this rollout.
Question 757
A small branch must use both Internet and private MPLS, and engineers assume the two underlays cannot coexist on one SD-WAN edge. The chosen correction is: Design distinct supported transport interfaces and TLOC colors with centralized path policy. Which additional predeployment check is most relevant?
- Validate encryption domains, anti-replay, MTU, NAT-T and rekey behavior before failover testing.
- Limit the extended broadcast domain and verify provider OAM and failover.
- Obtain documented path diversity evidence rather than relying on separate provider names.
- Validate underlay next hops and NAT traversal on each WAN interface independently.
Explanation
Correct Answer
D:Validate underlay next hops and NAT traversal on each WAN interface independently. This protects the intended outcome: The edge establishes intended tunnels over both transports and applications use their approved paths.
Incorrect Answers
A:That precaution belongs to another scenario: A site-to-site tunnel must protect financial payload confidentiality and integrity across the public internet. It is not the primary safeguard for this rollout.
B:That precaution belongs to another scenario: Two industrial sites require transparent delivery of a small set of Ethernet services and reject routing between their private LANs. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A bank contracts two MPLS providers but both fiber tails enter the building through the same conduit. It is not the primary safeguard for this rollout.
Question 758
A multicast network has active PIM neighbors but one edge switch suppresses IGMP reports after an access-layer topology change. The chosen correction is: Correct receiver membership handling and ensure snooping querier or routing interface behavior is consistent. Which additional predeployment check is most relevant?
- Map every potential bottleneck and avoid unnecessary policy complexity on uncongested links.
- Inventory controllers, NTP, logging, and backup requirements before restricting cross-segment paths.
- Confirm IGMP snooping querier placement and membership timeouts before changing PIM topology.
- Test RP reachability, register and join behavior under single-node failure.
Explanation
Correct Answer
C:Confirm IGMP snooping querier placement and membership timeouts before changing PIM topology. This protects the intended outcome: Receiver ports are present in membership tables and only eligible ports receive the stream.
Incorrect Answers
A:That precaution belongs to another scenario: A campus designs priority queues only on the access switch but ignores a congested upstream WAN edge. It is not the primary safeguard for this rollout.
B:That precaution belongs to another scenario: Two business units share one management VLAN with unrestricted access to each other's routers. It is not the primary safeguard for this rollout.
D:That precaution belongs to another scenario: A PIM-SM domain has active receivers but no working rendezvous-point reachability for new source registration. It is not the primary safeguard for this rollout.
Question 759
A designer proposes unequal-cost EIGRP load sharing for two paths whose topology prevents one path from meeting the feasibility condition. The chosen correction is: Select feasible successors that meet EIGRP feasibility requirements and use variance only on eligible paths. Which additional predeployment check is most relevant?
- Review route reachability and summary boundaries before introducing stub behavior.
- Validate advertised stub route classes and redundancy if the branch has multiple uplinks.
- Verify path attributes, platform multipath limits, and asymmetric application requirements.
- Inspect feasible distance and reported distance for candidate successors before rollout.
Explanation
Correct Answer
D:Inspect feasible distance and reported distance for candidate successors before rollout. This protects the intended outcome: Traffic shares only across qualified routes and failed successors do not create a loop.
Incorrect Answers
A: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.
B:That precaution belongs to another scenario: A branch EIGRP router advertises remote routes back into its hub and occasionally becomes a transit path between hubs. It is not the primary safeguard for this rollout.
C:That precaution belongs to another scenario: A campus border is configured with two equal-cost external BGP paths but only one is installed for traffic forwarding. It is not the primary safeguard for this rollout.
Question 760
A wireless access-point refresh increases PoE needs above the available 802.3at class on older switches. The chosen correction is: Specify access switch PoE capabilities and power budget that support the APs' required negotiated power levels. Which additional predeployment check is most relevant?
- Review platform compatibility and perform a maintenance-window failover test before promising hitless service.
- Compare model-specific power requirements with cable loss and redundant supply capacity.
- Verify platform multi-chassis capability and fate sharing before bundling cross-chassis links.
- Validate WLC and AP fabric roles against platform support and target mobility scope.
Explanation
Correct Answer
B:Compare model-specific power requirements with cable loss and redundant supply capacity. This protects the intended outcome: Each AP enables its intended radio features at full load without power denial or downshift.
Incorrect Answers
A:That precaution belongs to another scenario: A remote campus uses two distribution switches and requires nonstop gateway access during a planned supervisor replacement. It is not the primary safeguard for this rollout.
C: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.
D:That precaution belongs to another scenario: A fabric site needs a guest wireless SSID without extending the guest Layer 2 domain across the whole enterprise. It is not the primary safeguard for this rollout.
Designing Cisco Enterprise Networks (ENSLD) (300-420) Practice Tests
