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Question 410
A dual-provider BGP edge must prefer ISP A for outbound traffic, but inbound updates from A have a lower MED than B and engineers assume MED dictates every decision. Which observed result would most directly prove the design meets the intended goal?
- The IPv6 client resolves and accesses the approved IPv4 service without adopting IPv4 on the client.
- The accepted RIB contains the permitted default and no unintended provider prefixes.
- All advertised LAN /64s are distinct and can be summarized within the delegated /48 where topology permits.
- Internal BGP best-path selection prefers ISP A where the intended routes are otherwise eligible.
Explanation
Correct Answer
D:Use an appropriate local-preference policy inside the enterprise AS to set outbound exit preference. 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 IPv6-only client subnet must access a legacy IPv4-only web endpoint through an enterprise gateway. It does not verify the present outcome.
B:This observation relates to a different topology: An edge router receives a full BGP table where the security policy allows only the provider's approved default. It does not verify the present outcome.
C: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.
Question 411
A virtualized distribution pair uses one logical control plane and engineers assume it offers separate failure domains like two chassis in different buildings. Which observed result would most directly prove the design meets the intended goal?
- Loss of either PDU leaves the campus default gateway and upstream traffic operating.
- Control-plane endpoint mappings resolve and separate packet captures show VXLAN data forwarding between fabric edges.
- A tested hardware or supervisor failure meets application recovery objectives without unexpected shared dependencies.
- Switches participate in the expected common region and root placement is consistent per instance.
Explanation
Correct Answer
C:Evaluate physical fault domains and provide independent power, links, and control-plane recovery within the chosen abstraction. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: Two campus distribution routers each have a single power feed from the same rack PDU, yet the architecture counts them as separate fault domains. It does not verify the present outcome.
B:This observation relates to a different topology: An SD-Access architect assumes the fabric's LISP control plane transports all user packets like a data-plane tunnel. It does not verify the present outcome.
D: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.
Question 412
A company needs private predictable cloud connectivity to two regions but its design considers only commodity internet VPNs. Which observed result would most directly prove the design meets the intended goal?
- The receiver continues receiving timestamped samples during steady-state operation.
- Authorized cloud prefixes are reachable over intended private paths after one interconnect fails.
- The controller successfully reads and writes only the supported wireless policy nodes on target devices.
- Approved burst workloads operate across the private and public boundaries without unrestricted network trust.
Explanation
Correct Answer
B:Evaluate a dedicated cloud interconnect or partner/private WAN option with diverse regional termination and routing. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A support dashboard needs regular CPU and interface-rate samples even when values remain unchanged. It does not verify the present outcome.
C:This observation relates to a different topology: A Cisco-only controller needs platform-specific wireless policies that are not represented by the organization's standard OpenConfig model. It does not verify the present outcome.
D:This observation relates to a different topology: An organization hosts workloads in its owned private cloud and bursts selected approved applications to a public cloud while declaring this exclusively private deployment. It does not verify the present outcome.
Question 413
A provider's remote OOB management path is only 2 Mbps, while the network team sends continuous uncompressed telemetry streams at 5 Mbps. Which observed result would most directly prove the design meets the intended goal?
- Backup operations continue at lower priority without violating interactive video quality.
- Telemetry remains within service capacity and operators can still reach consoles under load.
- Receiver forwarding follows the intended tree state after source discovery and any supported SPT transition.
- An emergency administrator maintains workable session latency while backup transfer runs.
Explanation
Correct Answer
B:Rate-limit or aggregate nonessential management streams and preserve bandwidth for emergency control sessions. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A QoS controller marks all backup data DSCP AF41 while the provider honors it as a premium video class. It does not verify the present outcome.
C: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.
D:This observation relates to a different topology: A low-bandwidth remote management VPN carries huge nightly backup transfers that prevent emergency SSH access. It does not verify the present outcome.
Question 414
A regional healthcare group wants routed site separation within a provider-managed private WAN without building its own full mesh of tunnels. Which observed result would most directly prove the design meets the intended goal?
- Authorized branch prefixes appear within the appropriate VPN and survive a PE failure as contracted.
- Approved endpoints encrypt traffic while retaining the provider's intended any-to-any routing paths.
- Each branch exchanges only authorized VPN routes while the provider backbone transports traffic without L2 extension.
- Approved spoke-to-spoke traffic forms an appropriate direct overlay path after registration.
Explanation
Correct Answer
A:Select MPLS L3VPN service with CE-PE routing, per-customer VRFs and explicit route policy. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
B:This observation relates to a different topology: An organization needs any-to-any group-encrypted private WAN traffic but the new design proposes a traditional hub-and-spoke IPsec overlay with hub hairpins. It does not verify the present outcome.
C: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.
D:This observation relates to a different topology: A retail chain needs many spokes to make dynamic spoke-to-spoke tunnels without permanent full-mesh configuration. It does not verify the present outcome.
Question 415
Campus routers detect a fiber break only after long OSPF dead timers, missing a strict voice recovery target. Which observed result would most directly prove the design meets the intended goal?
- A failed path is withdrawn quickly enough that active voice sessions remain within the specified interruption budget.
- A representative prefix crosses the boundary once and retains deterministic return routing.
- Intercampus traffic follows authorized shortest feasible paths rather than unwanted data-center detours.
- Neighbor relationships recover while supported forwarding state remains stable during the tested restart.
Explanation
Correct Answer
A:Evaluate supported BFD-based fault detection and matching IGP convergence policy for the routed adjacency. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
B:This observation relates to a different topology: Two intercampus routers redistribute OSPF and EIGRP in both directions, making route origin hard to track. It does not verify the present outcome.
C:This observation relates to a different topology: A branch aggregation point has both IS-IS and OSPF neighbors with multiple equal-cost exits; traffic unexpectedly hairpins through a data center. It does not verify the present outcome.
D:This observation relates to a different topology: An NSF-capable router pair loses a control-plane process briefly and the design assumes all neighboring routers will preserve forwarding. It does not verify the present outcome.
Question 416
A network uses IS-IS with dual distribution routers and wants predictable traffic away from a low-bandwidth backup path. 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.
- Normal forwarding prefers the main path while failover selects the backup when primary reachability disappears.
- Authorized IPv4 partner sessions reach the selected IPv6 service through the documented translation path.
- Allowed external routes appear without reentering their origin routing domain on an alternate border.
Explanation
Correct Answer
B:Set consistent IS-IS link metrics reflecting intended primary and backup capacity and verify resulting shortest paths. 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.
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.
D: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.
Question 417
A multisite SD-WAN deployment uses one manager for configuration and assumes manager reachability is necessary for every packet of user data. Which observed result would most directly prove the design meets the intended goal?
- Services over the optical circuit remain isolated by the appropriate higher-layer controls.
- Only authorized multicast receivers on selected sites receive the required production feed.
- Existing permitted edge-to-edge tunnels continue carrying traffic across a management-plane interruption where supported.
- The branch establishes the required controlled overlay sessions without depending on unsupported unsolicited inbound access.
Explanation
Correct Answer
C:Design control/management resilience separately from WAN edge data-plane forwarding. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: A WAN team assumes DWDM wavelength multiplexing itself supplies packet-level route isolation between tenants. 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: An industrial site uses 4G LTE as primary WAN, and its routing team assumes public inbound addresses remain reachable through carrier-grade NAT. It does not verify the present outcome.
Question 418
A branch policy gives every queue an equal share although its database synchronization is delaying emergency call signaling. Which observed result would most directly prove the design meets the intended goal?
- Unit administrators can reach authorized nodes but are denied management of unrelated infrastructure.
- Critical signaling and voice meet their performance targets while bulk sync proceeds on its class.
- Legitimate multicast traffic arrives on the expected upstream interface without duplicates.
- Control-plane adjacencies and monitoring remain stable during representative congestion.
Explanation
Correct Answer
B:Allocate queue scheduling according to measured application criticality and minimum bandwidth needs. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: Two business units share one management VLAN with unrestricted access to each other's routers. It does not verify the present outcome.
C:This observation relates to a different topology: A campus carries multicast across dual uplinks and incorrectly assumes that equal-cost unicast routes guarantee both incoming multicast paths are valid. It does not verify the present outcome.
D:This observation relates to a different topology: A campus QoS policy gives low priority to routing keepalives and network monitoring, and routing adjacencies flap during congestion. It does not verify the present outcome.
Question 419
A network peers eBGP over a loopback with multiple routed hops and assumes a directly connected neighbor model. Which observed result would most directly prove the design meets the intended goal?
- The prefix exits through the intended ASBR and remains loop-free on failover.
- IPv6 packets traverse the IPv4-only transit without unintended address-family policy leaks.
- OSPF adjacencies establish only between intended authenticated peers and survive planned key changes.
- The eBGP session establishes over the routed path and routes remain reachable during a single underlay link failure.
Explanation
Correct Answer
D:Use a supported eBGP multihop design with reachable loopback endpoints and suitable TTL/security policy. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: An OSPF redistribution boundary introduces the same connected subnet from two ASBRs, resulting in inconsistent egress selection. It does not verify the present outcome.
B:This observation relates to a different topology: An organization needs to reach an IPv6 island over a provider network that carries IPv4 only for the next year. 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 420
A design extends SDA fabric across buildings on a WAN with 1500-byte MTU and assumes local campus performance will continue unchanged. Which observed result would most directly prove the design meets the intended goal?
- Control-plane endpoint mappings resolve and separate packet captures show VXLAN data forwarding between fabric edges.
- Neighbor relationships recover while supported forwarding state remains stable during the tested restart.
- Guest clients roam as designed and cannot access restricted enterprise segments.
- Intersite overlay flows survive the engineered path and meet their measured size and latency limits.
Explanation
Correct Answer
D:Evaluate supported multisite design with MTU, latency, encapsulation, and control-plane reachability constraints. Verify the resulting network behavior rather than relying only on the saved configuration.
Incorrect Answers
A:This observation relates to a different topology: An SD-Access architect assumes the fabric's LISP control plane transports all user packets like a data-plane tunnel. It does not verify the present outcome.
B:This observation relates to a different topology: An NSF-capable router pair loses a control-plane process briefly and the design assumes all neighboring routers will preserve forwarding. It does not verify the present outcome.
C: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.
Designing Cisco Enterprise Networks (ENSLD) (300-420) Practice Tests
