Cisco 300-420 Bundle

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” would remedy that alternative situation, but it would not correct the present issue: OSPF hierarchical inter-area connectivity depends on a stable backbone design and resilient area border connectivity.

“Choose a supported stub-area design consistently across the area and ensure the ABR provides an appropriate default route” is the supported response when a normal area floods external routing information that stub-capable branches may not need when a default route is sufficient. Here the decisive response is “Design redundant ABRs with valid backbone area connectivity and deterministic cost preferences for inter-area paths”, so that different intervention does not meet the stated requirement.

External Type 2 cost behavior does not account for internal cost in the same way as Type 1 when external metrics differ. “Select E1 or E2 route treatment to reflect the required exit preference, testing both external and internal metrics” applies to that other condition. The reported evidence is an enterprise creates several OSPF nonbackbone areas linked through a single fragile ABR with no alternate route into area zero; this alternative would address the wrong dependency.

That change concerns sd access cisco ise identity policy role, where Identity group classification requires a trusted policy source and onboarding process rather than arbitrary address-based role guessing. The reported issue instead stems from: Security group policy alone may not replace full virtual-network level route isolation where separate macrosegments are required.

That change concerns sd access redundant control plane nodes, where A single endpoint map/control-plane service is a common-mode availability risk even with redundant data-plane links. In this question the necessary remedy is “Design distinct fabric virtual networks with appropriate external borders and tightly defined shared services”, which this alternative does not provide.

That change concerns sd access multicast in overlay fabric, where Fabric overlay multicast support and replication design have specific control and data-plane requirements beyond simple underlay multicast reachability. The observed condition is a finance and guest population share the same fabric virtual network even though compliance requires independent routing tables and external access paths; this mechanism addresses another problem.

Carrier detection at the local switch does not necessarily detect loss of a remote routed neighbor or intermediate path. “Design suitable BFD sessions for supported routing peers with conservative scale-aware timer settings” would remedy that alternative situation, but it would not correct the present issue: unprotected edge-port fast transition can introduce topology-change or loop risks if another bridge is attached.

“Use supported graceful restart and nonstop forwarding features only where peer compatibility and forwarding state can be verified” is the supported response when routing graceful restart requires compatible neighbor capability and safe stale-route lifetimes, not merely redundant uplinks. Here the decisive response is “Apply supported PortFast or edge behavior with BPDU Guard and an approved exception procedure for genuine uplinks”, so that different intervention does not meet the stated requirement.

A virtualized or stacked switching design needs supported control, state and multichassis link mechanisms to act as one logical system. “Select a validated stacking or virtual-switch architecture and plan supervisor, interconnect and software compatibility” applies to that other condition. The reported evidence is a user-facing access port is configured as a fast transition edge port but an employee connects a small switch that starts sending BPDUs; this alternative would address the wrong dependency.

Extended nodes and ordinary fabric nodes have distinct supported roles and scale limits; uplink connection alone does not confer every fabric service. “Use supported extended-node topology with appropriate fabric-edge parent capacity and port-assignment design” would remedy that alternative situation, but it would not correct the present issue: physical underlay IP connectivity does not by itself establish appropriate inter-fabric transit, route exchange and segmentation policy.

“Size border nodes and redundant exits for N-minus-one load, applying failure-domain and traffic-engineering requirements” is the supported response when link redundancy within the fabric does not guarantee sufficient external border forwarding capacity during degraded operation. Here the decisive response is “Design supported fabric-to-fabric transit via qualified borders and consistent virtual-network route and security policy”, 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 two independent SD-Access fabrics need policy-governed intersite reachability, but engineers connect only their individual IP underlays and expect overlay virtual networks to merge; this alternative would address the wrong dependency.

That change concerns multicast designated router selection, where PIM DR election provides a defined designated router role on a multiaccess segment to avoid conflicting join responsibilities. The reported issue instead stems from: Source-specific multicast applications need supported source-aware receiver membership signaling, commonly IGMPv3 for IPv4.

That change concerns msdp interdomain active source sharing, where Independent rendezvous points do not automatically exchange all active-source information across ASM multicast domains. In this question the necessary remedy is “Design SSM-compatible group range, sender addressing and receiver IGMPv3 support end to end”, which this alternative does not provide.

That change concerns multicast source shortest path tree switchover, where ASM initially uses a shared RP tree and may switch to source-specific shortest-path forwarding according to design and platform behavior. The observed condition is a video delivery platform wants receivers to accept only one known multicast source per group but the access network uses receiver signaling that cannot express source preference; this mechanism addresses another problem.

Extending Layer 2 broadly across campus buildings increases loop, convergence and failure-domain exposure. “Design routed access where supported, using local Layer 3 boundaries and deterministic IGP connectivity between buildings” would remedy that alternative situation, but it would not correct the present issue: FHRP peers must exchange control messages in a correctly shared VLAN to maintain a single active forwarding role.

“Choose a documented VRRP preemption design with safe delay and reachability tracking that fits service stability goals” is the supported response when gateway role restoration depends on the selected FHRP protocol and its configured preemption settings, not priority numbers alone. Here the decisive response is “Restore approved VLAN trunk reachability and compatible HSRP group and timer settings across both devices”, so that different intervention does not meet the stated requirement.

A single physical gateway address makes host access depend on one distribution device even when a second gateway exists. “Design a supported FHRP virtual gateway with aligned priorities, Layer 2 reachability and safe failover between distribution switches” applies to that other condition. The reported evidence is two redundant distribution switches both believe they are HSRP active after a VLAN trunk blocks hello messages, causing inconsistent gateway ARP responses; this alternative would address the wrong dependency.

Premature use of a partially ready intermediate system can blackhole transit despite apparently formed control-plane neighbors. “Include restart and overload-bit behavior in IS-IS maintenance acceptance and failover testing” would remedy that alternative situation, but it would not correct the present issue: neighbor authentication parameters and permitted key windows must align or the routing protocol rejects peer messages.

“Audit redistribution route tags and policy match order whenever a new domain boundary is added” 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 “Maintain synchronized key-chain schedules and monitor EIGRP authentication failures around rotation windows”, so that different intervention does not meet the stated requirement.

Unnecessary specific-route propagation increases state and change sensitivity without providing required central policy detail. “Require prefix allocation consistency before EIGRP summarization is enabled in production” applies to that other condition. The reported evidence is two enterprise EIGRP neighbors cease exchanging routes after only one endpoint changes key identifiers during security hardening; this alternative would address the wrong dependency.

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. The reported issue instead stems from: Unfiltered inter-VRF route leaking can undermine segmentation even if each tenant has its own routing instance.

That change concerns campus convergence targets and bfd scale, where High session counts and excessively aggressive timers can exhaust control resources and cause false routing flaps. In this question the necessary remedy is “Export only authorized service prefixes and apply necessary packet access restrictions at the shared-services border”, which this alternative does not provide.

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 observed condition is a guest campus VRF is permitted to reach a shared DNS service but a broad route leak accidentally exposes internal management subnets; this mechanism addresses another problem.

Conventional iBGP full mesh grows quadratically and becomes costly to configure, observe and recover. “Test reflection path diversity and redundant reflector failure modes before retiring full-mesh peers” would remedy that alternative situation, but it would not correct the present issue: internal OSPF cost does not communicate an intended interconnect preference to the neighboring autonomous system.

“Separate inbound and outbound traffic-engineering objectives in BGP policy design documentation” is the supported response when AS-path prepending mainly affects remote path selection; outbound path preference within the local AS is commonly controlled with local preference. Here the decisive response is “Validate BGP policy precedence and provider rules instead of assuming MED overrides every upstream preference”, so that different intervention does not meet the stated requirement.

Local preference is not exported between autonomous systems, so changing it cannot directly govern external networks' inbound selection. “Avoid promising deterministic global inbound routing from prepends, and test provider-specific policy interactions” applies to that other condition. The reported evidence is a corporation connects twice to one upstream AS and wants to suggest a preferred entry point to that neighbor, yet edits only routing metrics inside its own OSPF core; this alternative would address the wrong dependency.

Default broadcast OSPF network behavior can elect designated routers even when the topology is only a two-router link. “Document OSPF network-type assumptions and test peer compatibility during link-provider migrations” would remedy that alternative situation, but it would not correct the present issue: unauthenticated routing adjacencies on a shared segment create topology-manipulation exposure and accidental peer acceptance.

“Capacity-plan BFD session counts and monitor instability before enabling aggressive timers across large deployments” 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 “Rotate OSPF peer credentials with planned maintenance and inventory every intended adjacency”, 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. “Perform automated prefix allowlist tests and route-leak simulations before modifying BGP transit peers” applies to that other condition. The reported evidence is a campus routing design permits unauthorized OSPF Hellos on shared distribution links, and security cannot prove peer identity; this alternative would address the wrong dependency.

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. The reported issue instead stems from: Policing enforces a rate by dropping or remarking excess packets, whereas shaping ordinarily smooths outbound bursts using buffers.

That change concerns voice priority queuing starvation, where An oversized or unbounded strict-priority queue can consume interface capacity and deny adequate service to other classes. In this question the necessary remedy is “Use shaping for traffic that can tolerate buffering and selective policing where a hard ingress contract is needed”, 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 design uses aggressive ingress policing for interactive video and expects the policer to buffer all bursts until bandwidth becomes available; this mechanism addresses another problem.