Cisco 300-420 Bundle

An SVI routed ACL does not necessarily inspect intra-VLAN switched frames that never reach Layer 3 forwarding. “Test actual Layer 2 forwarding paths before certifying an SVI-only rule as local east-west isolation” would remedy that alternative situation, but it would not correct the present issue: bidirectional multipoint redistribution without route tagging or authoritative direction can reintroduce routes into their source protocol.

“Set explicit maximum Layer 2 failure domains during new-building network approvals” is the supported response when extending Layer 2 broadly across campus buildings increases loop, convergence and failure-domain exposure. Here the decisive response is “Validate tags and filtering under loss of either redistribution border router”, so that different intervention does not meet the stated requirement.

A common routing instance cannot enforce independent overlapping IP destinations and controlled route exposure by itself. “Require security approval and route-leak testing for every campus shared-services exception” applies to that other condition. The reported evidence is two campus cores exchange OSPF and EIGRP routes across two border routers and route entries recirculate until suboptimal paths appear; this alternative would address the wrong dependency.

That change concerns openconfig cross-platform telemetry models, where OpenConfig provides vendor-neutral model definitions whose implemented paths and capabilities must still be validated per platform. The reported issue instead stems from: Standardized models do not necessarily represent every vendor-specific operational or configuration feature.

That change concerns ietf versus vendor YANG model portability, where Vendor-native data models may expose platform-specific schema that cannot be queried identically across different vendors. In this question the necessary remedy is “Use the supported Cisco native YANG model for the particular feature with platform and software-version capability checks”, 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 a controller needs to configure a specialized Cisco-only feature not represented by its generic OpenConfig model, yet developers insist the generic model must support it; this mechanism addresses another problem.

That change concerns mpls layer 3 vpn tenant separation, where A shared provider routing domain cannot preserve independent overlapping tenant address spaces and route targets without isolation. The reported issue instead stems from: Multipoint Ethernet services and many independent E-Line circuits have different Layer 2 forwarding and spanning-tree implications.

That change concerns layer 2 vpn transparent branch extension, where An MPLS Layer 3 VPN routes IP among separated CE networks rather than delivering a transparent Layer 2 Ethernet service. In this question the necessary remedy is “Choose appropriate Metro Ethernet point-to-point or multipoint service topology with explicit VLAN and loop-avoidance design”, which this alternative does not provide.

That change concerns dwdm optical backbone capacity, where Ordinary port-level upgrades may not meet aggregate fiber-capacity and distance requirements when the optical transport must host many independent wavelengths. The observed condition is a manufacturing campus buys point-to-point Ethernet links for twenty buildings but plans to treat the collection as a single broadcast mesh without loop controls; this mechanism addresses another problem.

That change concerns ipv6 subnet prefix length on end-user lan, where Typical Ethernet SLAAC uses /64 interface identifiers and ordinary host autoconfiguration expectations are not met by arbitrary longer access prefixes. The reported issue instead stems from: Provider-dependent global prefixes may require renumbering when upstream connectivity changes and do not replace a stable local-only design.

That change concerns dual stack migration dependency planning, where Network dual stacking alone does not add AAAA DNS records, IPv6 listening services, security policy or path validation to existing applications. In this question the necessary remedy is “Use an appropriately generated unique-local IPv6 prefix for suitable internal services alongside routed global addressing where Internet access is needed”, which this alternative does not provide.

That change concerns is-is level 1 and level 2 area topology, where IS-IS Level 1 operates within an area while Level 2 provides inter-area connectivity and should bound unwanted topology flooding. The observed condition is a campus requires internal IPv6 communication that survives ISP changes but uses only a provider-assigned global prefix for every local infrastructure service; this mechanism addresses another problem.

Policy percentages alone do not preserve service if critical aggregate traffic exceeds reduced failover link capacity. “Maintain separate primary and failover traffic budgets and test both periodically” would remedy that alternative situation, but it would not correct the present issue: in-band-only management can share a fault with the network being repaired, eliminating the ability to recover remotely.

“Audit management route import and export policy after topology changes and disaster recovery tests” 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 “Test the independent OOB path and break-glass credentials during scheduled resilience drills”, so that different intervention does not meet the stated requirement.

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” applies to that other condition. The reported evidence is a distributed business manages core routers only through their production VPN, and a routing incident removes both business forwarding and remote admin access; this alternative would address the wrong dependency.

That change concerns ospf route authentication consistency, where Unauthenticated routing adjacencies on a shared segment create topology-manipulation exposure and accidental peer acceptance. The reported issue instead stems from: Default broadcast OSPF network behavior can elect designated routers even when the topology is only a two-router link.

That change concerns BGP prefix filter outbound boundary, where Unrestricted BGP export policy exposes destinations not authorized for upstream announcement and risks routing leaks. In this question the necessary remedy is “Use supported point-to-point OSPF network type consistently on both sides where the physical design permits”, which this alternative does not provide.

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. The observed condition 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 mechanism addresses another problem.

Without class-based queue service, different traffic priorities may compete equally under congestion rather than receiving guaranteed minimum allocations. “Implement appropriate CBWFQ or platform-supported scheduler weights after classifying actual traffic” would remedy that alternative situation, but it would not correct the present issue: priority queuing alone cannot create bandwidth beyond circuit capacity, and too many concurrent sessions can oversubscribe voice allocation.

“Classify and mark before encryption or use supported trusted tunnel metadata and policy-based identification at appropriate endpoints” 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 “Design call admission or session limits based on codec overhead and failover bandwidth, with controlled class policies”, so that different intervention does not meet the stated requirement.

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” applies to that other condition. The reported evidence is a small branch has a 3 Mbps WAN with no admission control and permits twenty simultaneous high-bitrate voice sessions, causing severe jitter; this alternative would address the wrong dependency.

That change concerns BGP med neighboring exit choice, where Internal OSPF cost does not communicate an intended interconnect preference to the neighboring autonomous system. The reported issue instead stems from: Local preference is not exported between autonomous systems, so changing it cannot directly govern external networks' inbound selection.

That change concerns BGP next hop self across ibgp, where iBGP typically preserves the external next hop, which must be reachable through the internal routing infrastructure. In this question the necessary remedy is “Apply approved outbound AS-path prepending on the less-preferred transit and check provider acceptance and alternate routing”, which this alternative does not provide.

That change concerns BGP route reflector cluster design, where Conventional iBGP full mesh grows quadratically and becomes costly to configure, observe and recover. The observed condition is a multihomed public service wants remote networks to prefer one upstream for inbound traffic but changes only its own local preference; this mechanism addresses another problem.

That change concerns ipv4 summarization boundary alignment, where A /15 covers two consecutive aligned /16 networks and the selected /15 omits 10.66.0.0/16 while including unintended space. The reported issue instead stems from: A flat random allocation from the /48 wastes the opportunity for site-level hierarchy and complicates growth and route summarization.

That change concerns vlsm sized campus user allocation, where An IPv4 /27 ordinarily has only thirty usable host addresses, so it cannot accommodate the stated phones and gateway. In this question the necessary remedy is “Reserve logical per-site prefixes within the /48, allocate appropriate /64 LANs and maintain documented room for subnets and future services”, which this alternative does not provide.

That change concerns overlapping ipv4 address after acquisition, where Overlapping address spaces are ambiguous to ordinary destination-based routing and require unique addressing or deliberate translation boundaries. The observed condition is an organization receives an IPv6 /48 and assigns different arbitrary /64s to access LANs without reserving site blocks or a summarization scheme; this mechanism addresses another problem.

That change concerns campus stp root placement, where Without deliberate STP root design, Layer 2 forwarding paths may traverse inappropriate access hardware. The reported issue instead stems from: Carrier detection at the local switch does not necessarily detect loss of a remote routed neighbor or intermediate path.

That change concerns campus virtual switching platform abstraction, where A virtualized or stacked switching design needs supported control, state and multichassis link mechanisms to act as one logical system. In this question the necessary remedy is “Design suitable BFD sessions for supported routing peers with conservative scale-aware timer settings”, which this alternative does not provide.

That change concerns graceful restart campus routing continuity, where Routing graceful restart requires compatible neighbor capability and safe stale-route lifetimes, not merely redundant uplinks. The observed condition is a distribution-to-core Ethernet link stays administratively up while a transport device in the middle fails, and routing reconverges only after slow protocol timeouts; this mechanism addresses another problem.

Fabric overlay encapsulation adds overhead beyond ordinary IP reachability and depends on a healthy L3 underlay. “Provide resilient IP underlay reachability and adequate end-to-end MTU for supported fabric encapsulation” would remedy that alternative situation, but it would not correct the present issue: ordinary underlay reachability does not assign endpoint onboarding and VXLAN edge functions to a nonfabric access device.

“Design overlay forwarding paths with validated VXLAN reachability, fabric edge encapsulation and proper transport MTU” is the supported response when a fabric control plane supplies locator information, while the data plane uses supported VXLAN encapsulation to carry endpoint traffic. Here the decisive response is “Provision eligible access devices as supported fabric edge nodes and verify host onboarding and virtual network assignments”, so that different intervention does not meet the stated requirement.

Fabric control-plane endpoint-to-location mapping must reflect movement and be consistent with current host registration. “Use supported redundant LISP control-plane nodes and verify endpoint registration and mapping refresh behavior” applies to that other condition. The reported evidence 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 alternative would address the wrong dependency.