Cisco 300-420 Bundle

A common routing instance cannot enforce independent overlapping IP destinations and controlled route exposure by itself. “Design supported VRF-lite routing instances with carefully governed shared-services connectivity and separate interface assignments” would remedy that alternative situation, but it would not correct the present issue: link redundancy within the fabric does not guarantee sufficient external border forwarding capacity during degraded operation.

“Design supported fabric-to-fabric transit via qualified borders and consistent virtual-network route and security policy” is the supported response when physical underlay IP connectivity does not by itself establish appropriate inter-fabric transit, route exchange and segmentation policy. Here the decisive response is “Size border nodes and redundant exits for N-minus-one load, applying failure-domain and traffic-engineering requirements”, so that different intervention does not meet the stated requirement.

Fabric wireless requires supported controller and edge integration and consistent segmentation assignments for mobile clients. “Design the supported fabric wireless control-plane and data-plane integration with validated WLAN-to-VN mapping” applies to that other condition. The reported evidence is a fabric design has redundant edge uplinks but no redundant border capacity, so a single border failure overloads the remaining exit path; this alternative would address the wrong dependency.

That change concerns ospf external route type choice, where External Type 2 cost behavior does not account for internal cost in the same way as Type 1 when external metrics differ. The reported issue instead stems from: Unauthenticated routing adjacencies on a shared segment create topology-manipulation exposure and accidental peer acceptance.

That change concerns ospf bfd rapid failure detection, where Layer 1 carrier state may not reveal a downstream path failure and slow neighbor detection extends blackhole time. In this question the necessary remedy is “Enable the appropriate supported OSPF authentication and key rollout at trusted adjacency boundaries”, which this alternative does not provide.

That change concerns BGP prefix filter outbound boundary, where Unrestricted BGP export policy exposes destinations not authorized for upstream announcement and risks routing leaks. The observed condition is a campus routing design permits unauthorized OSPF Hellos on shared distribution links, and security cannot prove peer identity; this mechanism addresses another problem.

That change concerns YANG schema revision and path versioning, where Machine-readable data model revisions and capabilities can differ across platform versions even if management connectivity remains healthy. The reported issue instead stems from: Coarse periodic publication can delay visibility of short state transitions and is not equivalent to supported event-driven on-change reporting.

That change concerns netconf versus restconf transport selection, where NETCONF and RESTCONF share model-driven concepts but use different protocol transports, operation semantics and session behavior. In this question the necessary remedy is “Use supported on-change telemetry for the neighbor state path with safeguards for subscriber load and update volume”, which this alternative does not provide.

That change concerns periodic telemetry subscription timing, where On-change subscriptions report eligible state changes, not necessarily uniformly spaced observations required for some time-series analytics. The observed condition 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 mechanism addresses another problem.

Network dual stacking alone does not add AAAA DNS records, IPv6 listening services, security policy or path validation to existing applications. “Plan application-by-application dual-stack readiness including DNS, access controls, routing, management and rollback verification” would remedy that alternative situation, but it would not correct the present issue: a BGP TCP session does not automatically negotiate or advertise every address family without appropriate capabilities and policy.

“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 “Enable intended IPv6 unicast AFI/SAFI activation, reachable next hops and export filtering consistently on peers”, 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 two enterprise BGP routers establish a TCP session and exchange IPv4 reachability but their IPv6 networks remain absent after enabling the underlying IPv6 interface; this alternative would address the wrong dependency.

Without class-based queue service, different traffic priorities may compete equally under congestion rather than receiving guaranteed minimum allocations. “Review class allocation totals and projected peak demand as new applications join the WAN” would remedy that alternative situation, but it would not correct the present issue: DSCP semantics and provider class-of-service mappings are not necessarily preserved across an independent administrative domain.

“Validate classification location relative to encryption and encapsulation at design time” is the supported response when encryption hides much application payload from intermediate classifiers, so deep packet inspection may not see per-app content inside the tunnel. Here the decisive response is “Include the provider QoS contract and trust-domain mapping in WAN migration design packages”, 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 branch marks a critical application with DSCP 46, but the MPLS provider maps it into ordinary treatment because service-class translation was never agreed; this alternative would address the wrong dependency.

That change concerns saas paas iaas service responsibility split, where Cloud service models allocate operational responsibility differently; consuming PaaS normally shifts underlying host management while retaining customer data and access duties. The reported issue instead stems from: A hybrid deployment can transfer sensitive data or metadata across administrative and geographic boundaries even when application compute stays on-premises.

That change concerns periodic telemetry subscription timing, where On-change subscriptions report eligible state changes, not necessarily uniformly spaced observations required for some time-series analytics. In this question the necessary remedy is “Design controlled hybrid data flow, regional placement and access policies that satisfy residency and connectivity requirements”, which this alternative does not provide.

That change concerns YANG schema revision and path versioning, where Machine-readable data model revisions and capabilities can differ across platform versions even if management connectivity remains healthy. The observed condition is an enterprise has customer records that must remain in a private data center but moves its analytics control plane to a public cloud SaaS service without examining metadata export; this mechanism addresses another problem.

That change concerns sd access border node external integration, where Fabric overlay endpoints require a suitable border function to exchange external route reachability with nonfabric networks. The reported issue instead stems from: Ordinary underlay reachability does not assign endpoint onboarding and VXLAN edge functions to a nonfabric access device.

That change concerns sd access underlay mtu and ip reachability, where Fabric overlay encapsulation adds overhead beyond ordinary IP reachability and depends on a healthy L3 underlay. In this question the necessary remedy is “Provision eligible access devices as supported fabric edge nodes and verify host onboarding and virtual network assignments”, which this alternative does not provide.

That change concerns sd access vxlan data plane role, where A fabric control plane supplies locator information, while the data plane uses supported VXLAN encapsulation to carry endpoint traffic. The observed condition is a newly connected access switch is routed to the fabric core but attached endpoints never receive the expected overlay segmentation because the device is not operating as a fabric edge; this mechanism addresses another problem.

Multicast RPF typically checks the route back toward the source or RP, not merely whether a receiver destination is reachable. “Design correct multicast reverse paths and compatible unicast routing so upstream interfaces pass the RPF check” would remedy that alternative situation, but it would not correct the present issue: uncoordinated system clocks undermine log chronology, audit correlation and incident reconstruction.

“Select telemetry collection intervals and methods proportional to observed change rates and device capacity” is the supported response when overly aggressive polling can consume limited control-plane CPU and management bandwidth without improving decision quality. Here the decisive response is “Use resilient approved NTP sources with authenticated or trusted network delivery where supported”, so that different intervention does not meet the stated requirement.

ASM shared-tree setup may depend on reachable RP control functions that need deliberate redundancy. “Design supported redundant RP mechanisms with consistent group mappings and reachability across the multicast domain” applies to that other condition. The reported evidence is two distribution devices report the same routing flap five minutes apart because one device uses an unsynchronized clock; this alternative would address the wrong dependency.

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 reported issue instead stems from: Secure SD-WAN fabric admission requires authorized organization identifiers and valid identity trust, not just IP routing.

That change concerns cisco sd wan management and data path separation, where Using only the affected data-plane overlay for operational access can eliminate remote troubleshooting when the fabric fails. In this question the necessary remedy is “Design approved CA trust, certificate lifecycle and device authorization procedures for every control node and edge”, which this alternative does not provide.

That change concerns cisco sd wan management plane resilience, where Management availability and existing data-plane forwarding have different dependencies, while loss of manageability remains an operational risk. The observed condition is a new SD-WAN edge has Internet reachability but cannot join the fabric because controller identity and certificate chain checks are not satisfied; this mechanism addresses another problem.

Superior BPDUs on an untrusted downstream link can alter STP root selection unless the boundary is protected. “Separate trusted infrastructure trunk roles from untrusted tenant-facing links in STP templates” 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.

“Evaluate shared-control-plane failure risk and upgrade procedures when choosing platform abstraction over independent switches” 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 “Include root placement and protection checks in switch onboarding templates”, so that different intervention does not meet the stated requirement.

Routing graceful restart requires compatible neighbor capability and safe stale-route lifetimes, not merely redundant uplinks. “Test interactions between graceful restart, BFD and partial data-plane failure before relying on nonstop behavior” 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.

That change concerns sd wan edge last mile diversity, where Logical dual-circuit contracts may share a physical access path and suffer a common-cause outage. The reported issue instead stems from: A purely hub-and-spoke forwarding policy can add latency and load when the DMVPN design is intended to allow direct spoke shortcuts.

That change concerns cloud wan direct private connectivity choice, where An encrypted Internet overlay does not provide the same private carrier connectivity, SLA and traffic-engineering options as a qualified dedicated cloud circuit. In this question the necessary remedy is “Use a supported DMVPN phase and NHRP routing design that safely establishes eligible spoke-to-spoke tunnels”, which this alternative does not provide.

That change concerns ipsec encryption versus gre transport, where GRE provides encapsulation for multiple protocols but does not itself encrypt or authenticate payload confidentiality. The observed condition 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 mechanism addresses another problem.