Cisco 300-420 Bundle

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: coarse periodic publication can delay visibility of short state transitions and is not equivalent to supported event-driven on-change reporting.

“Match API protocol to the orchestrator requirements and supported device capabilities, including SSH/XML NETCONF or HTTP/RESTCONF workflows” is the supported response when NETCONF and RESTCONF share model-driven concepts but use different protocol transports, operation semantics and session behavior. Here the decisive response is “Use supported on-change telemetry for the neighbor state path with safeguards for subscriber load and update volume”, 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 network team wants immediate notification when a BGP neighbor state changes but configures a ten-minute periodic sample on the relevant state model; this alternative would address the wrong dependency.

Policy percentages alone do not preserve service if critical aggregate traffic exceeds reduced failover link capacity. “Create degraded-mode QoS and application admission policy based on backup capacity and essential services” would remedy that alternative situation, but it would not correct the present issue: input classification and policing operate on traffic entering an interface, while output scheduling applies to egress congestion.

“Run controlled traffic tests and inspect class and queue counters, delay and drop statistics end to end” is the supported response when a syntactically installed QoS policy does not establish that actual applications match intended classes or receive required forwarding treatment. Here the decisive response is “Place supported ingress policing and remarking at appropriate boundaries and egress queuing at the actual bottleneck”, so that different intervention does not meet the stated requirement.

Average throughput can hide instantaneous bursts and delay variation that disrupt real-time media even when link utilization seems moderate. “Reserve suitable queue and burst tolerance based on codec behavior, media priority and empirically observed peak load” applies to that other condition. The reported evidence is a campus operator attaches an output queue policy to a branch WAN interface but expects it to police inbound untrusted DSCP markings from the carrier; this alternative would address the wrong dependency.

Provider-dependent global prefixes may require renumbering when upstream connectivity changes and do not replace a stable local-only design. “Use an appropriately generated unique-local IPv6 prefix for suitable internal services alongside routed global addressing where Internet access is needed” would remedy that alternative situation, but it would not correct the present issue: premature use of a partially ready intermediate system can blackhole transit despite apparently formed control-plane neighbors.

“Design appropriate Level 1 and Level 2 adjacency placement with resilient L1/L2 border routers and reachable inter-area summaries” is the supported response when IS-IS Level 1 operates within an area while Level 2 provides inter-area connectivity and should bound unwanted topology flooding. Here the decisive response is “Use a supported startup overload-bit or similar transient-transit suppression design until the node is ready to forward”, 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. “Allocate /64 prefixes for SLAAC access segments while using more specialized lengths only in supported and justified designs” applies to that other condition. The reported evidence is a router with IS-IS adjacencies comes back after reboot before its forwarding resources and external routes finish loading, but its neighbors immediately use it as a transit node; this alternative would address the wrong dependency.

Local breakout bypasses central inspection unless equivalent secure edge controls and policy are deliberately placed. “Design approved branch egress security with local firewall, cloud security service or appropriate service chaining” would remedy that alternative situation, but it would not correct the present issue: dynamic spoke resolution needs correct NHRP network ID, authentication, hub mapping and reachable tunnel source rather than only a live Internet connection.

“Compare direct cloud private interconnect with managed Internet VPN based on security, bandwidth, route exchange and service commitments” is the supported response when an encrypted Internet overlay does not provide the same private carrier connectivity, SLA and traffic-engineering options as a qualified dedicated cloud circuit. Here the decisive response is “Align supported NHRP and tunnel registration settings and verify the hub can map the spoke's current public transport address”, so that different intervention does not meet the stated requirement.

Logical dual-circuit contracts may share a physical access path and suffer a common-cause outage. “Choose WAN edge circuits with validated last-mile, provider and facility diversity where the service recovery target requires it” applies to that other condition. The reported evidence is after replacing a branch Internet router, its DMVPN tunnel interface can reach the public network but the spoke no longer appears as registered at the hub; this alternative would address the wrong dependency.

A syntactically installed QoS policy does not establish that actual applications match intended classes or receive required forwarding treatment. “Run controlled traffic tests and inspect class and queue counters, delay and drop statistics end to end” would remedy that alternative situation, but it would not correct the present issue: traffic classification order and policy constructs can cause broad conditions to overshadow intended more-specific class handling.

“Reserve suitable queue and burst tolerance based on codec behavior, media priority and empirically observed peak load” is the supported response when average throughput can hide instantaneous bursts and delay variation that disrupt real-time media even when link utilization seems moderate. Here the decisive response is “Refine class-map criteria and supported policy evaluation to classify the real-time flows before generic groups”, so that different intervention does not meet the stated requirement.

Policy percentages alone do not preserve service if critical aggregate traffic exceeds reduced failover link capacity. “Create degraded-mode QoS and application admission policy based on backup capacity and essential services” applies to that other condition. The reported evidence is a provider WAN policy places a broad match-any business group before a specific real-time collaboration class, so important voice traffic gets generic treatment; this alternative would address the wrong dependency.

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: local breakout bypasses central inspection unless equivalent secure edge controls and policy are deliberately placed.

“Choose a supported multicast distribution and replication approach with measured receiver count and transport constraints” is the supported response when naive unicast replication can consume excessive WAN capacity, while multicast support depends on platform and overlay design. Here the decisive response is “Design approved branch egress security with local firewall, cloud security service or appropriate service chaining”, so that different intervention does not meet the stated requirement.

Remote-only controller dependencies and insufficient regional capacity can degrade onboarding, resiliency and convergence at scale. “Design supported regional controller and overlay architecture with redundancy, policy consistency and documented capacity limits” applies to that other condition. The reported evidence is a branch enables direct SaaS Internet breakout to improve performance but the original design assumes all egress is filtered by the data center firewall; this alternative would address the wrong dependency.

That change concerns qos policing versus buffering behavior, where Policing enforces a rate by dropping or remarking excess packets, whereas shaping ordinarily smooths outbound bursts using buffers. The reported issue instead stems from: A high-speed physical port does not imply equal committed service rate, so uncontrolled bursts can be discarded in the provider network.

That change concerns diffserv versus intserv service model, where Per-flow IntServ state scales differently from aggregated DiffServ classes and can become operationally expensive for large multi-site deployments. In this question the necessary remedy is “Shape outbound traffic to a suitable rate below the provider policer and apply useful internal priority queues”, which this alternative does not provide.

That change concerns qos trust boundary at user access, where Trusting unvalidated endpoint DSCP markings allows unauthorized traffic to consume preferential network resources. The observed condition 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 mechanism addresses another problem.

Static transport preference does not substitute for application-aware path decisions using measured latency, loss and jitter. “Create supported application-aware routing policy with validated SLA class thresholds and fallback behavior” would remedy that alternative situation, but it would not correct the present issue: local interface carrier may remain up when upstream service fails, so a static route without health tracking can blackhole traffic.

“Use a security-enforcing hub design or distributed inspection architecture with explicit policy for branch-to-branch traffic” is the supported response when shortcut VPN topology changes can bypass required inspection if the WAN policy assumes every flow transits a central hub. Here the decisive response is “Use supported service probing and tracked next-hop or routing convergence to withdraw an unusable primary path”, so that different intervention does not meet the stated requirement.

Multiple logical VLANs on the same physical CE and provider device do not provide independent failure domains. “Design separate CE devices, access paths and service-provider terminations in accordance with the required availability objective” applies to that other condition. The reported evidence is a branch prefers fiber Internet over backup DSL but its static primary default route remains installed after an upstream outage beyond the local Ethernet handoff; 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: local log storage and rollover cannot substitute for reliable centralized timestamped security event retention.

“Test the independent OOB path and break-glass credentials during scheduled resilience drills” is the supported response when in-band-only management can share a fault with the network being repaired, eliminating the ability to recover remotely. Here the decisive response is “Review logging health and retention policy across all management routing contexts”, so that different intervention does not meet the stated requirement.

A common routing table broadens the management attack surface and increases risk of route or ACL leakage. “Audit management route import and export policy after topology changes and disaster recovery tests” applies to that other condition. The reported evidence is a campus router logs only locally and loses fault evidence after flash rotation, despite a requirement for long-term security investigation; this alternative would address the wrong dependency.

In-band-only management can share a fault with the network being repaired, eliminating the ability to recover remotely. “Provide secure out-of-band management through independent transport, power and authentication suitable for critical nodes” would remedy that alternative situation, but it would not correct the present issue: without proper management traffic classification and minimum bandwidth, congestion can starve necessary operations traffic.

“Create a supported management VRF or equivalent separated context and tightly controlled shared services as needed” 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 “Classify authentic management flows and allocate controlled minimum service within the WAN's QoS policy”, so that different intervention does not meet the stated requirement.

Local log storage and rollover cannot substitute for reliable centralized timestamped security event retention. “Design redundant remote syslog collectors with protected transport, appropriate facilities and retention controls” applies to that other condition. The reported evidence is a WAN runs at capacity during remote backup jobs and incident responders lose SSH and telemetry access precisely when troubleshooting is needed; 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. “Document analytics cadence requirements before selecting telemetry subscription mode” would remedy that alternative situation, but it would not correct the present issue: private transport does not automatically enforce tenant segmentation or prevent unintended route exchange into cloud environments.

“Review provider location and device diversity rather than treating two logical virtual interfaces as two physical links” is the supported response when logical network separation on one physical direct-connect facility does not eliminate common power, provider or meet-me-room failures. Here the decisive response is “Audit cloud gateway, route-target and BGP export policy at each new private cloud interconnect”, so that different intervention does not meet the stated requirement.

TLS mutual authentication depends on valid identity and trust configuration, independent of basic network reachability. “Monitor certificate expiration and automate approved renewal across telemetry collectors and devices” applies to that other condition. The reported evidence is a financial institution wants dedicated provider L3VPN connectivity to cloud private resources and proposes exporting every enterprise VRF into one common cloud virtual network; this alternative would address the wrong dependency.