Cisco 300-420 Bundle

RP location affects shared-tree path efficiency and control resilience for ASM groups and can create a remote common-mode dependency. “Choose strategically located and redundant RPs considering source and receiver topology, routing cost and failover” would remedy that alternative situation, but it would not correct the present issue: source-specific multicast applications need supported source-aware receiver membership signaling, commonly IGMPv3 for IPv4.

“Evaluate supported SPT threshold and source-tree design for bandwidth and latency goals without creating RPF inconsistencies” is the supported response when ASM initially uses a shared RP tree and may switch to source-specific shortest-path forwarding according to design and platform behavior. Here the decisive response is “Design SSM-compatible group range, sender addressing and receiver IGMPv3 support end to end”, so that different intervention does not meet the stated requirement.

PIM DR election provides a defined designated router role on a multiaccess segment to avoid conflicting join responsibilities. “Design suitable PIM interface priorities and neighbor reachability for predictable designated-router selection” applies to that other condition. The reported evidence is a video delivery platform wants receivers to accept only one known multicast source per group but the access network uses receiver signaling that cannot express source preference; this alternative would address the wrong dependency.

BGP aggregation can hide component failures and attract traffic for unreachable portions of the summarized prefix. “Choose an aggregate policy with reviewed component-route dependencies, conservative discard behavior and correct reachability design” would remedy that alternative situation, but it would not correct the present issue: unrestricted BGP export policy exposes destinations not authorized for upstream announcement and risks routing leaks.

“Deploy supported BFD for the intended OSPF peers, validate timers against platform capacity and test false-positive risk” is the supported response when layer 1 carrier state may not reveal a downstream path failure and slow neighbor detection extends blackhole time. Here the decisive response is “Apply explicit approved outbound prefix filters at the eBGP boundary and validate maximum prefix expectations”, so that different intervention does not meet the stated requirement.

Unauthenticated routing adjacencies on a shared segment create topology-manipulation exposure and accidental peer acceptance. “Enable the appropriate supported OSPF authentication and key rollout at trusted adjacency boundaries” applies to that other condition. The reported evidence is a branch BGP edge learns a public provider default plus private corporate specifics and accidentally advertises internal /24s back to the provider; this alternative would address the wrong dependency.

Independent rendezvous points do not automatically exchange all active-source information across ASM multicast domains. “Maintain explicit source and RP boundary policy in interdomain multicast peering arrangements” would remedy that alternative situation, but it would not correct the present issue: random early detection is usually better aligned with responsive TCP queues than with high-priority delay-sensitive voice traffic.

“Review class allocation totals and projected peak demand as new applications join the WAN” is the supported response when without class-based queue service, different traffic priorities may compete equally under congestion rather than receiving guaranteed minimum allocations. Here the decisive response is “Validate platform queue and drop algorithm selection for each application class”, so that different intervention does not meet the stated requirement.

DSCP semantics and provider class-of-service mappings are not necessarily preserved across an independent administrative domain. “Include the provider QoS contract and trust-domain mapping in WAN migration design packages” applies to that other condition. The reported evidence is a network team enables WRED on the expedited voice queue and expects random early drops to improve low-latency real-time delivery; this alternative would address the wrong dependency.

FHRP peers must exchange control messages in a correctly shared VLAN to maintain a single active forwarding role. “Restore approved VLAN trunk reachability and compatible HSRP group and timer settings across both devices” would remedy that alternative situation, but it would not correct the present issue: traditional active-standby first-hop redundancy does not by itself provide the desired per-client gateway load distribution.

“Design a supported FHRP virtual gateway with aligned priorities, Layer 2 reachability and safe failover between distribution switches” is the supported response when a single physical gateway address makes host access depend on one distribution device even when a second gateway exists. Here the decisive response is “Consider GLBP where supported or a different routed access and anycast design, based on platform capability and operational needs”, so that different intervention does not meet the stated requirement.

FHRP presence alone may not account for upstream path viability without appropriate object or interface tracking. “Track the required upstream path and decrement priority enough for a healthy standby gateway to assume forwarding” applies to that other condition. The reported evidence is a large access VLAN needs multiple distribution gateways to forward client traffic concurrently, but the proposed HSRP design forwards all hosts through one active router; this alternative would address the wrong dependency.

That change concerns BGP next hop self across ibgp, where iBGP typically preserves the external next hop, which must be reachable through the internal routing infrastructure. The reported issue instead stems from: Protocol adjacency and IPv4 routes do not alone establish correct IPv6 reachability, interface addressing or address-family support.

That change concerns eigrp stub branch query containment, where Unbounded EIGRP query scope and nontransit spokes can prolong active route computation across a large topology. In this question the necessary remedy is “Implement supported IS-IS IPv6 reachability with interface family configuration and consistent topology preferences”, which this alternative does not provide.

That change concerns is-is adjacency authentication design, where An unprotected adjacency trust boundary can admit unauthorized IS-IS control messages into a routing domain. The observed condition is a network has existing IS-IS IPv4 reachability and adds IPv6-only applications, but the design assumes IPv4 reachability automatically creates IPv6 forwarding information; this mechanism addresses another problem.

Stateful inspection needs coherent bidirectional flow visibility, while independent routing cost choices can create asymmetric paths. “Select a topology and route policy that maintain suitable symmetric inspected paths or supported state sharing” would remedy that alternative situation, but it would not correct the present issue: available PoE power budget and per-port capabilities determine whether simultaneous endpoint power requirements can be met.

“Deploy suitable port security or 802.1X/MAB policies with sensible violation and recovery handling for endpoint types” is the supported response when without port security or identity-aware access control, a simple access port may learn multiple endpoint MAC addresses without limitation. Here the decisive response is “Calculate endpoint power demand, switch capacity and redundancy margins and choose appropriate power supplies or models”, so that different intervention does not meet the stated requirement.

Ordinary directed and local broadcasts do not automatically cross routed boundaries, so an explicit authorized delivery design is required. “Design secure supported WoL relays, proxy agents or local management distribution rather than exposing unrestricted broadcasts” applies to that other condition. The reported evidence is a network redesign adds video endpoints to every access port but budgets only for switch port count, ignoring PoE class and aggregate power draw; this alternative would address the wrong dependency.

Neighbor authentication parameters and permitted key windows must align or the routing protocol rejects peer messages. “Maintain synchronized key-chain schedules and monitor EIGRP authentication failures around rotation windows” would remedy that alternative situation, but it would not correct the present issue: IS-IS Level 1 operates within an area while Level 2 provides inter-area connectivity and should bound unwanted topology flooding.

“Include restart and overload-bit behavior in IS-IS maintenance acceptance and failover testing” is the supported response when premature use of a partially ready intermediate system can blackhole transit despite apparently formed control-plane neighbors. Here the decisive response is “Review IS-IS level boundaries whenever branch count grows or a site moves between geographic areas”, so that different intervention does not meet the stated requirement.

Typical Ethernet SLAAC uses /64 interface identifiers and ordinary host autoconfiguration expectations are not met by arbitrary longer access prefixes. “Validate IPv6 prefix lengths against actual endpoint SLAAC and Neighbor Discovery requirements before deployment” applies to that other condition. The reported evidence is an enterprise runs IS-IS across two geographic areas but requires every Level 1 router to store all other areas' detailed link-state information; this alternative would address the wrong dependency.

Multipoint Ethernet services and many independent E-Line circuits have different Layer 2 forwarding and spanning-tree implications. “Choose appropriate Metro Ethernet point-to-point or multipoint service topology with explicit VLAN and loop-avoidance design” would remedy that alternative situation, but it would not correct the present issue: logical transport labels or TLOCs do not inherently represent independent circuits, carrier facilities or last-mile paths.

“Design approved CA trust, certificate lifecycle and device authorization procedures for every control node and edge” is the supported response when secure SD-WAN fabric admission requires authorized organization identifiers and valid identity trust, not just IP routing. Here the decisive response is “Map TLOCs to genuinely diverse approved transport interfaces and validate policy-based failover”, so that different intervention does not meet the stated requirement.

Using only the affected data-plane overlay for operational access can eliminate remote troubleshooting when the fabric fails. “Provide an appropriately secured independent management path or out-of-band recovery access for critical WAN edges” applies to that other condition. The reported evidence is two SD-WAN colors are configured for a branch but both use the same physical Internet interface and carrier, despite a requirement for physical WAN diversity; this alternative would address the wrong dependency.

Without proper management traffic classification and minimum bandwidth, congestion can starve necessary operations traffic. “Keep management class membership restricted to approved control services and monitor for abuse” would remedy that alternative situation, but it would not correct the present issue: legacy community strings do not provide SNMPv3's user-based authentication and encryption capabilities needed by the policy.

“Audit management route import and export policy after topology changes and disaster recovery tests” is the supported response when a common routing table broadens the management attack surface and increases risk of route or ACL leakage. Here the decisive response is “Rotate SNMPv3 credentials and test monitoring continuity across device replacements”, so that different intervention does not meet the stated requirement.

In-band-only management can share a fault with the network being repaired, eliminating the ability to recover remotely. “Test the independent OOB path and break-glass credentials during scheduled resilience drills” applies to that other condition. The reported evidence is a large enterprise collects SNMP interface counters using a shared SNMPv2 community across all regions and must meet per-user authentication and privacy controls; this alternative would address the wrong dependency.

On-change subscriptions report eligible state changes, not necessarily uniformly spaced observations required for some time-series analytics. “Choose supported periodic or sample telemetry publication with a suitable interval for the planning metric” would remedy that alternative situation, but it would not correct the present issue: standardized models do not necessarily represent every vendor-specific operational or configuration feature.

“Select supported OpenConfig telemetry modules, verify revisions and normalize exceptions without assuming universal coverage” is the supported response when openConfig provides vendor-neutral model definitions whose implemented paths and capabilities must still be validated per platform. Here the decisive response is “Use the supported Cisco native YANG model for the particular feature with platform and software-version capability checks”, so that different intervention does not meet the stated requirement.

Vendor-native data models may expose platform-specific schema that cannot be queried identically across different vendors. “Prefer a suitable standards-based IETF model for portable interface telemetry, documenting implementation gaps and vendor extensions” applies to that other condition. The reported evidence is a controller needs to configure a specialized Cisco-only feature not represented by its generic OpenConfig model, yet developers insist the generic model must support it; this alternative would address the wrong dependency.

Policing enforces a rate by dropping or remarking excess packets, whereas shaping ordinarily smooths outbound bursts using buffers. “Document burst tolerance and discard implications when choosing policing or shaping for each class” would remedy that alternative situation, but it would not correct the present issue: a high-speed physical port does not imply equal committed service rate, so uncontrolled bursts can be discarded in the provider network.

“Audit QoS trust maps when onboarding new endpoint types or enabling unmanaged switch ports” is the supported response when trusting unvalidated endpoint DSCP markings allows unauthorized traffic to consume preferential network resources. Here the decisive response is “Revalidate shaping rates against provider CIR and accounting overhead after circuit or device changes”, so that different intervention does not meet the stated requirement.

An oversized or unbounded strict-priority queue can consume interface capacity and deny adequate service to other classes. “Review queue bandwidth guarantees and peak-rate policing as service demand changes” applies to that other condition. The reported evidence is a branch sends 1 Gbps bursts into an Ethernet handoff while its provider contract allows only 100 Mbps and drops excess traffic unpredictably; this alternative would address the wrong dependency.