Cisco 300-420 Bundle

An oversized or unbounded strict-priority queue can consume interface capacity and deny adequate service to other classes. “Reserve low-latency priority treatment for justified real-time traffic with controlled bandwidth and balanced class allocations” would remedy that alternative situation, but it would not correct the present issue: naive replicated unicast can consume far more shared-link capacity than a suitable multicast tree for many receivers.

“Enable appropriate PIM and IGMP behavior on intended routed interfaces and validate RP and RPF reachability” is the supported response when PIM sparse mode forwarding relies on supported multicast routing and receiver membership along the required multicast distribution tree. Here the decisive response is “Assess multicast replication at branching points or other supported content distribution design with receiver policy”, so that different intervention does not meet the stated requirement.

Multicast RPF decisions can be sensitive to unicast path selection, including ECMP and asymmetric routing behavior. “Align multicast source reachability and acceptable RPF design with supported ECMP handling and stable upstream selection” applies to that other condition. The reported evidence is a regional network distributes one 20 Mbps live event to sixty branches by sending sixty independent copies across the same core link; this alternative would address the wrong dependency.

That change concerns hierarchical ipv4 addressing plan, where Randomly scattered branch subnets prevent region-level summarization and make routing and change control unnecessarily complex. The reported issue instead stems from: Internal OSPF cost does not communicate an intended interconnect preference to the neighboring autonomous system.

That change concerns BGP route reflector cluster design, where Conventional iBGP full mesh grows quadratically and becomes costly to configure, observe and recover. In this question the necessary remedy is “Use supported BGP MED where appropriate, coordinate the provider's comparison behavior and keep resilient alternate exits”, which this alternative does not provide.

That change concerns BGP as path prepending inbound engineering, where Local preference is not exported between autonomous systems, so changing it cannot directly govern external networks' inbound selection. The observed condition is a corporation connects twice to one upstream AS and wants to suggest a preferred entry point to that neighbor, yet edits only routing metrics inside its own OSPF core; this mechanism addresses another problem.

An IPv4 /27 ordinarily has only thirty usable host addresses, so it cannot accommodate the stated phones and gateway. “Include realistic utilization forecasts and host-capacity arithmetic in IP addressing design signoff rather than relying on prefix labels” would remedy that alternative situation, but it would not correct the present issue: conventional iBGP full mesh grows quadratically and becomes costly to configure, observe and recover.

“Validate BGP policy precedence and provider rules instead of assuming MED overrides every upstream preference” is the supported response when internal OSPF cost does not communicate an intended interconnect preference to the neighboring autonomous system. Here the decisive response is “Test reflection path diversity and redundant reflector failure modes before retiring full-mesh peers”, so that different intervention does not meet the stated requirement.

Local preference is not exported between autonomous systems, so changing it cannot directly govern external networks' inbound selection. “Avoid promising deterministic global inbound routing from prepends, and test provider-specific policy interactions” applies to that other condition. The reported evidence is an internal BGP deployment expands to twenty routers using full-mesh sessions and new routers are added without a scalable peer plan; this alternative would address the wrong dependency.

Logical network separation on one physical direct-connect facility does not eliminate common power, provider or meet-me-room failures. “Design redundant cloud interconnects with suitable facility diversity, BGP and controlled Internet or secondary private fallback” would remedy that alternative situation, but it would not correct the present issue: NETCONF and RESTCONF share model-driven concepts but use different protocol transports, operation semantics and session behavior.

“Use supported on-change telemetry for the neighbor state path with safeguards for subscriber load and update volume” is the supported response when coarse periodic publication can delay visibility of short state transitions and is not equivalent to supported event-driven on-change reporting. Here the decisive response is “Match API protocol to the orchestrator requirements and supported device capabilities, including SSH/XML NETCONF or HTTP/RESTCONF workflows”, so that different intervention does not meet the stated requirement.

Repeated broad request-response polling can impose higher overhead than selective model-driven subscription updates for suitable telemetry. “Use platform-supported model-driven telemetry subscriptions for required state paths with sensible reporting intervals and collector capacity” applies to that other condition. The reported evidence is a controller team chooses NETCONF for an HTTP-native integration solely because both interfaces use YANG models and assumes their framing and transports are interchangeable; this alternative would address the wrong dependency.

DSCP semantics and provider class-of-service mappings are not necessarily preserved across an independent administrative domain. “Negotiate and implement DSCP-to-provider-CoS mapping and verify marking at each trust boundary” would remedy that alternative situation, but it would not correct the present issue: RP location affects shared-tree path efficiency and control resilience for ASM groups and can create a remote common-mode dependency.

“Apply supported multicast group or source boundary filtering at the appropriate WAN and tenant interfaces” is the supported response when without explicit multicast boundary control, group advertisements or forwarding may extend beyond authorized trust domains. Here the decisive response is “Choose strategically located and redundant RPs considering source and receiver topology, routing cost and failover”, so that different intervention does not meet the stated requirement.

Naive replicated unicast can consume far more shared-link capacity than a suitable multicast tree for many receivers. “Assess multicast replication at branching points or other supported content distribution design with receiver policy” applies to that other condition. The reported evidence is an enterprise places its single PIM rendezvous point at a remote edge site with unstable connectivity and sees long join delays for the entire multicast domain; this alternative would address the wrong dependency.

Legacy community strings do not provide SNMPv3's user-based authentication and encryption capabilities needed by the policy. “Rotate SNMPv3 credentials and test monitoring continuity across device replacements” would remedy that alternative situation, but it would not correct the present issue: without class-based queue service, different traffic priorities may compete equally under congestion rather than receiving guaranteed minimum allocations.

“Recalculate concurrent-call capacity whenever codec, provider CIR or secondary WAN path changes” is the supported response when priority queuing alone cannot create bandwidth beyond circuit capacity, and too many concurrent sessions can oversubscribe voice allocation. Here the decisive response is “Review class allocation totals and projected peak demand as new applications join the WAN”, so that different intervention does not meet the stated requirement.

Random early detection is usually better aligned with responsive TCP queues than with high-priority delay-sensitive voice traffic. “Validate platform queue and drop algorithm selection for each application class” applies to that other condition. The reported evidence is a WAN link has three business traffic classes but the design uses only a best-effort FIFO queue, creating unpredictable delay during peaks; this alternative would address the wrong dependency.

That change concerns rapid spanning tree edge port guard, where Unprotected edge-port fast transition can introduce topology-change or loop risks if another bridge is attached. The reported issue instead stems from: Stateful inspection needs coherent bidirectional flow visibility, while independent routing cost choices can create asymmetric paths.

That change concerns border route aggregation blackhole case, where A summary advertised by a border without valid components can attract and blackhole traffic during partial network failures. In this question the necessary remedy is “Select a topology and route policy that maintain suitable symmetric inspected paths or supported state sharing”, which this alternative does not provide.

That change concerns equal cost site routing load sharing, where Physical redundancy does not imply control-plane equal-cost path installation or useful flow distribution. The observed condition is a campus distribution redesign installs a stateful firewall on one inter-building path while a lower-cost IGP return route bypasses that firewall; this mechanism addresses another problem.

An unsegmented overlay routing context can make trust-boundary errors more likely even if some edge access rules exist. “Use separate service VPN or VRF contexts with explicit leak rules and security policy at authorized shared-service borders” would remedy that alternative situation, but it would not correct the present issue: uncontrolled multihoming can select unpredictable exits and cause asymmetry or suboptimal paths under provider changes.

“Negotiate and implement supported provider service MTU and customer handoff frame sizes including encapsulation requirements” is the supported response when service encapsulation consumes transport overhead and can exceed an underlay MTU that was sized only for native Ethernet payloads. Here the decisive response is “Define local preference, inbound announcement policy and health tracking based on primary and backup business requirements”, so that different intervention does not meet the stated requirement.

Local interface carrier may remain up when upstream service fails, so a static route without health tracking can blackhole traffic. “Use supported service probing and tracked next-hop or routing convergence to withdraw an unusable primary path” applies to that other condition. The reported evidence is an enterprise connects to two providers and wants symmetric business traffic behavior but simply allows both defaults with no designed routing policies; this alternative would address the wrong dependency.

That change concerns ipsec traffic selector scope, where VPN session status can be healthy while mismatched crypto ACLs or traffic selectors omit the application flow. The reported issue instead stems from: IP reachability does not imply that IKE versions, cryptographic proposals, identities and authentication settings agree across peers.

That change concerns mpls layer 3 vpn extranet reachability, where Tenant route separation blocks cross-VPN reachability until carefully controlled route-target import/export rules make the intended service available. In this question the necessary remedy is “Plan supported matching IKE/IPsec transforms and identity validation with staged security upgrades on both gateways”, which this alternative does not provide.

That change concerns gre tunnel mtu and fragmentation, where Encapsulation and encryption overhead reduce effective path MTU, and missing PMTUD control messages can stall large packets. The observed condition is two enterprise VPN gateways can ping one another but fail to establish a protected site-to-site tunnel after one side moves to a stronger IKE encryption suite; this mechanism addresses another problem.

Unprotected edge-port fast transition can introduce topology-change or loop risks if another bridge is attached. “Periodically test edge-port protections and review exceptions for meeting rooms and shared desks” would remedy that alternative situation, but it would not correct the present issue: a single endpoint map/control-plane service is a common-mode availability risk even with redundant data-plane links.

“Monitor identity-policy synchronization and handle unknown or unauthenticated endpoint roles explicitly” is the supported response when identity group classification requires a trusted policy source and onboarding process rather than arbitrary address-based role guessing. Here the decisive response is “Model controller and node availability separately from physical fabric underlay paths”, so that different intervention does not meet the stated requirement.

Fabric overlay multicast support and replication design have specific control and data-plane requirements beyond simple underlay multicast reachability. “Document platform-specific multicast scalability and multicast-versus-unicast replication tradeoffs” applies to that other condition. The reported evidence is a campus fabric has one control-plane node that maintains all endpoint registrations, and a planned node upgrade makes roaming users unreachable; this alternative would address the wrong dependency.

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” would remedy that alternative situation, but it would not correct the present issue: without deliberate STP root design, Layer 2 forwarding paths may traverse inappropriate access hardware.

“Select a validated stacking or virtual-switch architecture and plan supervisor, interconnect and software compatibility” is the supported response when a virtualized or stacked switching design needs supported control, state and multichassis link mechanisms to act as one logical system. Here the decisive response is “Set primary and backup STP roots on appropriate distribution devices and validate bridge priority and path costs”, so that different intervention does not meet the stated requirement.

Unprotected edge-port fast transition can introduce topology-change or loop risks if another bridge is attached. “Apply supported PortFast or edge behavior with BPDU Guard and an approved exception procedure for genuine uplinks” applies to that other condition. The reported evidence is a campus has redundant access trunks but an unmanaged access switch wins spanning-tree root after it comes online with an unexpectedly favorable bridge priority; this alternative would address the wrong dependency.