Cisco 300-420 Bundle

Fabric control-plane endpoint-to-location mapping must reflect movement and be consistent with current host registration. “Monitor control-plane registration freshness and duplicate endpoint identities in multibuilding fabrics” would remedy that alternative situation, but it would not correct the present issue: a fabric control plane supplies locator information, while the data plane uses supported VXLAN encapsulation to carry endpoint traffic.

“Evaluate border redundancy, route advertisement scope and external underlay handoff before deployment” is the supported response when fabric overlay endpoints require a suitable border function to exchange external route reachability with nonfabric networks. Here the decisive response is “Separate control-plane mapping checks from data-plane tunnel validation in incident runbooks”, so that different intervention does not meet the stated requirement.

Ordinary underlay reachability does not assign endpoint onboarding and VXLAN edge functions to a nonfabric access device. “Validate fabric-edge software, port roles and endpoint registration during site migration” applies to that other condition. The reported evidence is a campus engineer describes LISP mapping updates as the mechanism transporting user data between fabric edges and neglects overlay tunnel reachability; this alternative would address the wrong dependency.

Randomly scattered branch subnets prevent region-level summarization and make routing and change control unnecessarily complex. “Use an authoritative IP address management registry with reservation, collision checks and explicit aggregation ownership for new sites” would remedy that alternative situation, but it would not correct the present issue: a /15 covers two consecutive aligned /16 networks and the selected /15 omits 10.66.0.0/16 while including unintended space.

“Perform overlap detection in IPAM during mergers and document all temporary translation rules and decommissioning milestones” is the supported response when overlapping address spaces are ambiguous to ordinary destination-based routing and require unique addressing or deliberate translation boundaries. Here the decisive response is “Require automated prefix containment and component-reachability validation on every proposed aggregate route advertisement”, so that different intervention does not meet the stated requirement.

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” applies to that other condition. The reported evidence is an engineer advertises 10.64.0.0/15 to summarize 10.64.0.0/16 and 10.66.0.0/16, causing traffic for one site to be routed outside its intended aggregation boundary; this alternative would address the wrong dependency.

GNMI is a model-driven management interface commonly using gRPC streaming and structured path/value messages rather than a generic webpage. “Implement a supported gNMI client with secure gRPC connectivity and a valid Subscribe request for modeled paths” would remedy that alternative situation, but it would not correct the present issue: logical network separation on one physical direct-connect facility does not eliminate common power, provider or meet-me-room failures.

“Design supported cloud on-ramp or cloud gateway integration with controlled routing, identity and service security policy” is the supported response when traditional centralized route topology can add delay and consume backbone capacity even when local cloud on-ramp options are available. Here the decisive response is “Design redundant cloud interconnects with suitable facility diversity, BGP and controlled Internet or secondary private fallback”, so that different intervention does not meet the stated requirement.

Private transport does not automatically enforce tenant segmentation or prevent unintended route exchange into cloud environments. “Integrate MPLS L3VPN with approved cloud private routing and select per-tenant VRF and gateway route policies” applies to that other condition. The reported evidence is a business integrates a regional network with public cloud using one dedicated physical circuit and assumes a separate routing VLAN on the same facility provides true disaster tolerance; this alternative would address the wrong dependency.

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” would remedy that alternative situation, but it would not correct the present issue: a purely hub-and-spoke forwarding policy can add latency and load when the DMVPN design is intended to allow direct spoke shortcuts.

“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 “Use a supported DMVPN phase and NHRP routing design that safely establishes eligible spoke-to-spoke tunnels”, so that different intervention does not meet the stated requirement.

GRE provides encapsulation for multiple protocols but does not itself encrypt or authenticate payload confidentiality. “Combine supported GRE transport with an appropriate IPsec protection design, or select a secure alternative meeting multicast needs” applies to that other condition. The reported evidence is a national enterprise uses a DMVPN hub for branch IPsec tunnels but all branch-to-branch voice calls hairpin through the distant hub despite viable direct underlay paths; this alternative would address the wrong dependency.

Conventional iBGP full mesh grows quadratically and becomes costly to configure, observe and recover. “Introduce redundant route reflectors with appropriate client hierarchy and loop-prevention identifiers” 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.

“Use a supported startup overload-bit or similar transient-transit suppression design until the node is ready to forward” 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 “Design appropriate Level 1 and Level 2 adjacency placement with resilient L1/L2 border routers and reachable inter-area summaries”, 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 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.

Dynamic spoke resolution needs correct NHRP network ID, authentication, hub mapping and reachable tunnel source rather than only a live Internet connection. “Align supported NHRP and tunnel registration settings and verify the hub can map the spoke's current public transport address” would remedy that alternative situation, but it would not correct the present issue: an encrypted Internet overlay does not provide the same private carrier connectivity, SLA and traffic-engineering options as a qualified dedicated cloud circuit.

“Choose WAN edge circuits with validated last-mile, provider and facility diversity where the service recovery target requires it” is the supported response when logical dual-circuit contracts may share a physical access path and suffer a common-cause outage. Here the decisive response is “Compare direct cloud private interconnect with managed Internet VPN based on security, bandwidth, route exchange and service commitments”, so that different intervention does not meet the stated requirement.

GRE provides encapsulation for multiple protocols but does not itself encrypt or authenticate payload confidentiality. “Combine supported GRE transport with an appropriate IPsec protection design, or select a secure alternative meeting multicast needs” applies to that other condition. The reported evidence is a regulated enterprise runs latency-sensitive cloud workloads but routes all traffic through a public Internet VPN and needs predictable private provider connectivity; this alternative would address the wrong dependency.

Translation adds stateful dependencies and application edge cases that may be unnecessary when a controlled native dual-stack phase is viable. “Select native dual stack for capable segments and reserve translation for real IPv4-only boundaries with documented requirements” would remedy that alternative situation, but it would not correct the present issue: IPv4-only security rules do not automatically enforce the same trust boundary for IPv6 traffic on a dual-stack path.

“Budget tunnel overhead in MTU planning, preserve required ICMPv6 control messages and validate endpoints' segment sizes” is the supported response when overlay headers reduce usable path MTU and blocked ICMPv6 Packet Too Big feedback can prevent Path MTU Discovery. Here the decisive response is “Develop explicit IPv6 security policies for routing, access, logging and required ICMPv6 control behavior”, so that different intervention does not meet the stated requirement.

IPv6-only clients cannot communicate with IPv4-only services without supported translation and suitable destination synthesis. “Design appropriate NAT64 plus DNS64 service boundaries, DNS behavior and application compatibility exceptions” applies to that other condition. The reported evidence is a security design filters outbound IPv4 branch traffic but turns on IPv6 at WAN gateways without corresponding IPv6 ACLs and telemetry; this alternative would address the wrong dependency.

That change concerns asymmetric campus firewall placement, where Stateful inspection needs coherent bidirectional flow visibility, while independent routing cost choices can create asymmetric paths. The reported issue instead stems from: High session counts and excessively aggressive timers can exhaust control resources and cause false routing flaps.

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 “Model required convergence classes and scale BFD deployment selectively on critical routed interfaces”, 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 design mandates subsecond link failure reaction on hundreds of campus peers and enables aggressive BFD for every adjacency without capacity estimation; this mechanism addresses another problem.

That change concerns qos validation with actual queue counters, where A syntactically installed QoS policy does not establish that actual applications match intended classes or receive required forwarding treatment. The reported issue instead stems from: Multicast RPF typically checks the route back toward the source or RP, not merely whether a receiver destination is reachable.

That change concerns ntp time quality in network operations, where Uncoordinated system clocks undermine log chronology, audit correlation and incident reconstruction. In this question the necessary remedy is “Design correct multicast reverse paths and compatible unicast routing so upstream interfaces pass the RPF check”, which this alternative does not provide.

That change concerns management telemetry sampling capacity, where Overly aggressive polling can consume limited control-plane CPU and management bandwidth without improving decision quality. The observed condition is a multicast receiver sees no video even though the router has a unicast route to the receiver, and engineers inspect only destination forwarding; this mechanism addresses another problem.

Gateway role restoration depends on the selected FHRP protocol and its configured preemption settings, not priority numbers alone. “Document whether automatic takeover or stability-first non-preemption is intended for each critical VLAN” would remedy that alternative situation, but it would not correct the present issue: an SVI routed ACL does not necessarily inspect intra-VLAN switched frames that never reach Layer 3 forwarding.

“Coordinate IPAM, summarization and discard behavior before opening new campus subnet ranges” is the supported response when missing site-level address summarization increases routing state and exposes the WAN to local campus topology churn. Here the decisive response is “Test actual Layer 2 forwarding paths before certifying an SVI-only rule as local east-west isolation”, so that different intervention does not meet the stated requirement.

Extending Layer 2 broadly across campus buildings increases loop, convergence and failure-domain exposure. “Set explicit maximum Layer 2 failure domains during new-building network approvals” applies to that other condition. The reported evidence is two servers share a VLAN, but security engineers place an ACL only on the routed SVI and assume it filters all direct Layer 2 traffic between them; this alternative would address the wrong dependency.

Trusting unvalidated endpoint DSCP markings allows unauthorized traffic to consume preferential network resources. “Audit QoS trust maps when onboarding new endpoint types or enabling unmanaged switch ports” would remedy that alternative situation, but it would not correct the present issue: an oversized or unbounded strict-priority queue can consume interface capacity and deny adequate service to other classes.

“Evaluate per-flow state, class counts and provider behavior before committing to any QoS architecture” is the supported response when per-flow IntServ state scales differently from aggregated DiffServ classes and can become operationally expensive for large multi-site deployments. Here the decisive response is “Review queue bandwidth guarantees and peak-rate policing as service demand changes”, so that different intervention does not meet the stated requirement.

A high-speed physical port does not imply equal committed service rate, so uncontrolled bursts can be discarded in the provider network. “Revalidate shaping rates against provider CIR and accounting overhead after circuit or device changes” applies to that other condition. The reported evidence is an enterprise places voice, video, backups and database replication in one strict-priority class, and ordinary business applications starve during a site backup; this alternative would address the wrong dependency.