Cisco 300-420 Bundle

A shared provider routing domain cannot preserve independent overlapping tenant address spaces and route targets without isolation. “Select a supported MPLS L3VPN design using separate VPN routing tables and approved route-target import/export policy” would remedy that alternative situation, but it would not correct the present issue: an MPLS Layer 3 VPN routes IP among separated CE networks rather than delivering a transparent Layer 2 Ethernet service.

“Choose appropriate Metro Ethernet point-to-point or multipoint service topology with explicit VLAN and loop-avoidance design” is the supported response when multipoint Ethernet services and many independent E-Line circuits have different Layer 2 forwarding and spanning-tree implications. Here the decisive response is “Choose an eligible provider Layer 2 VPN or Ethernet private line design if extending a broadcast domain is genuinely required”, so that different intervention does not meet the stated requirement.

Mobile backup is useful only if real coverage, policy, cost and failure independence support required branch services. “Design cellular failover with tested signal strength, provider diversity, data-plan capacity and selective critical traffic routing” applies to that other condition. The reported evidence is a retailer wants two facilities to operate on one Ethernet broadcast domain across a managed provider network, but its proposed ordinary routed MPLS L3VPN does not transport Ethernet frames; this alternative would address the wrong dependency.

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” would remedy that alternative situation, but it would not correct the present issue: management availability and existing data-plane forwarding have different dependencies, while loss of manageability remains an operational risk.

“Map TLOCs to genuinely diverse approved transport interfaces and validate policy-based failover” is the supported response when logical transport labels or TLOCs do not inherently represent independent circuits, carrier facilities or last-mile paths. Here the decisive response is “Design redundant supported SD-WAN Managers with backup, RBAC and regional management reachability as appropriate”, so that different intervention does not meet the stated requirement.

Data-plane tunnel presence does not guarantee that control-plane route advertisement and segmentation policy deliver needed service prefixes. “Validate OMP route advertisements and centralized policy across controllers with intended VPN and TLOC eligibility” applies to that other condition. The reported evidence is an enterprise relies on a single remote management platform for all SD-WAN configuration and assumes controller outage is equivalent to immediate edge forwarding loss; this alternative would address the wrong dependency.

That change concerns sd wan regional scale and control topology, where Remote-only controller dependencies and insufficient regional capacity can degrade onboarding, resiliency and convergence at scale. The reported issue instead stems from: Using only the affected data-plane overlay for operational access can eliminate remote troubleshooting when the fabric fails.

That change concerns cisco sd wan controller certificate trust, where Secure SD-WAN fabric admission requires authorized organization identifiers and valid identity trust, not just IP routing. In this question the necessary remedy is “Provide an appropriately secured independent management path or out-of-band recovery access for critical WAN edges”, which this alternative does not provide.

That change concerns cisco sd wan transport tloc diversity, where Logical transport labels or TLOCs do not inherently represent independent circuits, carrier facilities or last-mile paths. The observed condition is operations wants to reach branch edges for troubleshooting through an overlay VPN that might be down during a widespread incident; this mechanism addresses another problem.

Overlapping address spaces are ambiguous to ordinary destination-based routing and require unique addressing or deliberate translation boundaries. “Choose a phased renumbering design or carefully scoped NAT between the overlapping domains with clear DNS and application dependencies” would remedy that alternative situation, but it would not correct the present issue: layer 1 carrier state may not reveal a downstream path failure and slow neighbor detection extends blackhole time.

“Apply explicit approved outbound prefix filters at the eBGP boundary and validate maximum prefix expectations” is the supported response when unrestricted BGP export policy exposes destinations not authorized for upstream announcement and risks routing leaks. Here the decisive response is “Deploy supported BFD for the intended OSPF peers, validate timers against platform capacity and test false-positive risk”, 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 an OSPF transport remains physically up during a middle-network failure and the route takes too long to reconverge using default Hello and dead timers; this alternative would address the wrong dependency.

That change concerns stp loop guard unidirectional failure, where A non-designated STP port losing expected control messages can create a loop if it incorrectly assumes the superior path vanished. The reported issue instead stems from: Superior BPDUs on an untrusted downstream link can alter STP root selection unless the boundary is protected.

That change concerns mst region boundary mismatch, where MST region membership requires consistent region identifier, revision and VLAN mapping rather than matching only some VLAN names. In this question the necessary remedy is “Enable Root Guard on appropriate downstream designated ports and keep intended root roles explicit”, which this alternative does not provide.

That change concerns per vlan stp scalability, where A per-VLAN spanning-tree model scales protocol state with VLAN count and may become less efficient than suitable aggregated instances. The observed condition is an access switch connected to a third-party tenant device begins sending superior BPDUs and causes the building's STP root to move into the tenant network; this mechanism addresses another problem.

NETCONF can expose candidate datastores, locking and commit operations where supported, unlike assuming every management interface has equivalent transactions. “Document datastore capabilities and session failure recovery before using transactional network automation” would remedy that alternative situation, but it would not correct the present issue: openConfig provides vendor-neutral model definitions whose implemented paths and capabilities must still be validated per platform.

“Test cross-vendor schema availability before promising identical API behavior for every device” is the supported response when vendor-native data models may expose platform-specific schema that cannot be queried identically across different vendors. Here the decisive response is “Version model support matrices and review schema revisions before monitoring-platform upgrades”, so that different intervention does not meet the stated requirement.

Machine-readable data model revisions and capabilities can differ across platform versions even if management connectivity remains healthy. “Include API schema contract tests and rollback in every network software upgrade program” applies to that other condition. The reported evidence is a monitoring platform wants consistent operational telemetry across diverse vendor routers, but teams conflate OpenConfig definitions with the device's vendor-specific CLI configuration; this alternative would address the wrong dependency.

Unnecessary specific-route propagation increases state and change sensitivity without providing required central policy detail. “Apply well-bounded route summaries at distribution interfaces only after validating component networks and discard consequences” would remedy that alternative situation, but it would not correct the present issue: an EIGRP feasible successor must satisfy its feasibility condition relative to the successor's feasible distance to prevent loops.

“Use explicit tag-based redistribution policy, defined metrics and directional filters at well-documented borders” is the supported response when uncontrolled bidirectional redistribution can reintroduce routes, create loops and lose source-of-truth route preference. Here the decisive response is “Review reported and feasible distances and design valid loop-free alternatives rather than forcing an invalid candidate”, so that different intervention does not meet the stated requirement.

EIGRP unequal-cost load sharing is not enabled simply because multiple routes exist and is constrained by feasibility and variance. “Assess feasible successors and apply an approved variance design with realistic traffic-share expectations” applies to that other condition. The reported evidence is an enterprise asks EIGRP to install an alternate path solely because the alternate advertised distance is low, without checking the feasibility condition; this alternative would address the wrong dependency.

Repeated broad request-response polling can impose higher overhead than selective model-driven subscription updates for suitable telemetry. “Measure both publication and collector overhead rather than assuming every telemetry stream is automatically cheaper” 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.

“Validate method, status-code and error-body handling in network API client tests” is the supported response when RESTCONF uses resource-oriented HTTP methods with defined read and write semantics, so GET is not an appropriate configuration write operation. Here the decisive response is “Test event delivery under frequent flaps and avoid overwhelming collection systems with unbounded updates”, so that different intervention does not meet the stated requirement.

NETCONF and RESTCONF share model-driven concepts but use different protocol transports, operation semantics and session behavior. “Run interoperability tests for protocol authentication, payload encoding and error handling before deployment” 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.

An EIGRP feasible successor must satisfy its feasibility condition relative to the successor's feasible distance to prevent loops. “Review reported and feasible distances and design valid loop-free alternatives rather than forcing an invalid candidate” would remedy that alternative situation, but it would not correct the present issue: default broadcast OSPF network behavior can elect designated routers even when the topology is only a two-router link.

“Enable intended IPv6 unicast AFI/SAFI activation, reachable next hops and export filtering consistently on peers” is the supported response when a BGP TCP session does not automatically negotiate or advertise every address family without appropriate capabilities and policy. Here the decisive response is “Use supported point-to-point OSPF network type consistently on both sides where the physical design permits”, so that different intervention does not meet the stated requirement.

Unrestricted BGP export policy exposes destinations not authorized for upstream announcement and risks routing leaks. “Apply explicit approved outbound prefix filters at the eBGP boundary and validate maximum prefix expectations” applies to that other condition. The reported evidence is a point-to-point Ethernet transport has only two routers, but operations wants to avoid unnecessary DR/BDR behavior from a broadcast network type; this alternative would address the wrong dependency.

A BGP TCP session does not automatically negotiate or advertise every address family without appropriate capabilities and policy. “Include negotiated address-family and next-hop checks in every BGP peer acceptance procedure” would remedy that alternative situation, but it would not correct the present issue: BGP aggregation can hide component failures and attract traffic for unreachable portions of the summarized prefix.

“Monitor tunnel endpoint resilience and account for encapsulation overhead in path MTU design” is the supported response when an IPv4-only underlay cannot natively carry IPv6 forwarding without an overlay or other transition capability. Here the decisive response is “Audit aggregate announcements and child route health before and after regional outages”, so that different intervention does not meet the stated requirement.

Graceful restart depends on both peers' supported capabilities and bounded stale-route handling, not merely a routing session name. “Test graceful-restart interactions with BFD and forwarding readiness during platform changes” applies to that other condition. The reported evidence is a border advertises a BGP aggregate for several site prefixes but after one internal site is withdrawn, the advertised summary still attracts traffic to its unavailable block; this alternative would address the wrong dependency.

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.