Cisco 300-420 Bundle

A per-VLAN spanning-tree model scales protocol state with VLAN count and may become less efficient than suitable aggregated instances. “Assess MST or Layer 3 access boundaries against actual traffic steering and availability requirements” would remedy that alternative situation, but it would not correct the present issue: a non-designated STP port losing expected control messages can create a loop if it incorrectly assumes the superior path vanished.

“Enable Root Guard on appropriate downstream designated ports and keep intended root roles explicit” is the supported response when superior BPDUs on an untrusted downstream link can alter STP root selection unless the boundary is protected. Here the decisive response is “Use Loop Guard on appropriate non-edge STP links and deploy complementary unidirectional link detection where supported”, so that different intervention does not meet the stated requirement.

Physical link-up is insufficient to guarantee bidirectional signal integrity, which can affect control-plane protocols and forwarding. “Enable appropriate UDLD modes on supported fiber links and validate shutdown and recovery procedures” applies to that other condition. The reported evidence is one of two redundant STP links stops receiving BPDUs due to a unidirectional fault but remains physically up, risking a blocked port transitioning to forwarding; this alternative would address the wrong dependency.

Bidirectional multipoint redistribution without route tagging or authoritative direction can reintroduce routes into their source protocol. “Apply explicit redistribution filters, tags, metrics and domain ownership at each boundary with deliberate failure fallback” would remedy that alternative situation, but it would not correct the present issue: extending Layer 2 broadly across campus buildings increases loop, convergence and failure-domain exposure.

“Plan contiguous campus address blocks and advertise valid site summaries at L3 distribution or WAN boundaries” 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 “Design routed access where supported, using local Layer 3 boundaries and deterministic IGP connectivity between buildings”, so that different intervention does not meet the stated requirement.

An SVI routed ACL does not necessarily inspect intra-VLAN switched frames that never reach Layer 3 forwarding. “Design supported VACL, private VLAN or separate VLAN segmentation according to local traffic patterns and platform capabilities” applies to that other condition. The reported evidence is a multicampus organization extends each access VLAN over multiple buildings to preserve gateway placement, creating a large shared spanning-tree fault domain; this alternative would address the wrong dependency.

Identity group classification requires a trusted policy source and onboarding process rather than arbitrary address-based role guessing. “Integrate the fabric with appropriate Cisco ISE identity policy and validated endpoint profiling or authentication flows” would remedy that alternative situation, but it would not correct the present issue: security group policy alone may not replace full virtual-network level route isolation where separate macrosegments are required.

“Design supported control-plane node redundancy and test endpoint registration continuity during node loss” is the supported response when a single endpoint map/control-plane service is a common-mode availability risk even with redundant data-plane links. Here the decisive response is “Design distinct fabric virtual networks with appropriate external borders and tightly defined shared services”, so that different intervention does not meet the stated requirement.

Fabric overlay multicast support and replication design have specific control and data-plane requirements beyond simple underlay multicast reachability. “Select a supported SD-Access multicast forwarding model and test receivers across fabric edges and virtual networks” applies to that other condition. The reported evidence is a finance and guest population share the same fabric virtual network even though compliance requires independent routing tables and external access paths; this alternative would address the wrong dependency.

A summary advertised by a border without valid components can attract and blackhole traffic during partial network failures. “Tie aggregate advertisement to required downstream reachability or redesign summarization and redundancy accordingly” would remedy that alternative situation, but it would not correct the present issue: stateful inspection needs coherent bidirectional flow visibility, while independent routing cost choices can create asymmetric paths.

“Export only authorized service prefixes and apply necessary packet access restrictions at the shared-services border” is the supported response when unfiltered inter-VRF route leaking can undermine segmentation even if each tenant has its own routing instance. Here the decisive response is “Select a topology and route policy that maintain suitable symmetric inspected paths or supported state sharing”, so that different intervention does not meet the stated requirement.

Physical redundancy does not imply control-plane equal-cost path installation or useful flow distribution. “Align appropriate IGP costs and supported equal-cost multipath settings with capacity and symmetric path requirements” applies to that other condition. The reported evidence is a campus distribution redesign installs a stateful firewall on one inter-building path while a lower-cost IGP return route bypasses that firewall; this alternative would address the wrong dependency.

That change concerns cloud direct connect redundant circuits, where Logical network separation on one physical direct-connect facility does not eliminate common power, provider or meet-me-room failures. The reported issue instead stems from: Cloud service models allocate operational responsibility differently; consuming PaaS normally shifts underlying host management while retaining customer data and access duties.

That change concerns hybrid cloud data residency architecture, where A hybrid deployment can transfer sensitive data or metadata across administrative and geographic boundaries even when application compute stays on-premises. In this question the necessary remedy is “Choose a suitable SaaS, PaaS or IaaS architecture with an explicit responsibility matrix for app, identity, runtime and infrastructure”, which this alternative does not provide.

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. The observed condition is a development team moves a legacy application to a managed PaaS runtime but budgets for patching its underlying virtual machine host while leaving application access controls unowned; this mechanism addresses another problem.

EtherChannel members need compatible Layer 2 settings and negotiated bundling state to represent a correct logical link. “Standardize member configuration and use supported LACP negotiation and consistency checks for the port channel” would remedy that alternative situation, but it would not correct the present issue: a conventional port channel cannot span unrelated independent switches without a supported multichassis or stacking mechanism.

“Calculate endpoint power demand, switch capacity and redundancy margins and choose appropriate power supplies or models” is the supported response when available PoE power budget and per-port capabilities determine whether simultaneous endpoint power requirements can be met. Here the decisive response is “Use a validated multichassis EtherChannel, virtual switching, or routed dual-homing design for platform capabilities”, so that different intervention does not meet the stated requirement.

Ordinary directed and local broadcasts do not automatically cross routed boundaries, so an explicit authorized delivery design is required. “Design secure supported WoL relays, proxy agents or local management distribution rather than exposing unrestricted broadcasts” applies to that other condition. The reported evidence is a downstream server is dual-homed to two distribution devices that use an ordinary standalone EtherChannel design unsupported across separate control systems; 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.

“Combine supported GRE transport with an appropriate IPsec protection design, or select a secure alternative meeting multicast needs” is the supported response when GRE provides encapsulation for multiple protocols but does not itself encrypt or authenticate payload confidentiality. 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.

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” 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.

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. The reported issue instead stems from: Repeated broad request-response polling can impose higher overhead than selective model-driven subscription updates for suitable telemetry.

That change concerns restconf http method and resource scope, where RESTCONF uses resource-oriented HTTP methods with defined read and write semantics, so GET is not an appropriate configuration write operation. In this question the necessary remedy is “Use platform-supported model-driven telemetry subscriptions for required state paths with sensible reporting intervals and collector capacity”, which this alternative does not provide.

That change concerns on change telemetry event notifications, where Coarse periodic publication can delay visibility of short state transitions and is not equivalent to supported event-driven on-change reporting. The observed condition is a WAN operations team polls thousands of interface counters through legacy SNMP every few seconds and saturates device management CPU during incidents; this mechanism addresses another problem.

That change concerns cloud on ramp sd wan policy, where Traditional centralized route topology can add delay and consume backbone capacity even when local cloud on-ramp options are available. The reported issue instead stems from: NETCONF and RESTCONF share model-driven concepts but use different protocol transports, operation semantics and session behavior.

That change concerns restconf http method and resource scope, where RESTCONF uses resource-oriented HTTP methods with defined read and write semantics, so GET is not an appropriate configuration write operation. In this question the necessary remedy is “Match API protocol to the orchestrator requirements and supported device capabilities, including SSH/XML NETCONF or HTTP/RESTCONF workflows”, which this alternative does not provide.

That change concerns on change telemetry event notifications, where Coarse periodic publication can delay visibility of short state transitions and is not equivalent to supported event-driven on-change reporting. The observed condition is a controller team chooses NETCONF for an HTTP-native integration solely because both interfaces use YANG models and assumes their framing and transports are interchangeable; this mechanism addresses another problem.

Tenant route separation blocks cross-VPN reachability until carefully controlled route-target import/export rules make the intended service available. “Design an approved extranet or shared-services VPN import/export model with explicit prefix filters and security enforcement” would remedy that alternative situation, but it would not correct the present issue: IP reachability does not imply that IKE versions, cryptographic proposals, identities and authentication settings agree across peers.

“Update both peers' protected prefix definitions and routing design with least-privilege permitted flows” is the supported response when VPN session status can be healthy while mismatched crypto ACLs or traffic selectors omit the application flow. Here the decisive response is “Plan supported matching IKE/IPsec transforms and identity validation with staged security upgrades on both gateways”, so that different intervention does not meet the stated requirement.

Traditional point-to-point encryption tunnel meshes may add unnecessary topology and scale complexity for a trusted private routed underlay. “Evaluate supported GET VPN group key distribution and policy design where technology and business requirements fit” applies to that other condition. The reported evidence is two enterprise VPN gateways can ping one another but fail to establish a protected site-to-site tunnel after one side moves to a stronger IKE encryption suite; this alternative would address the wrong dependency.

A /15 covers two consecutive aligned /16 networks and the selected /15 omits 10.66.0.0/16 while including unintended space. “Create aligned aggregates that cover actual component prefixes and validate binary prefix boundaries and the destination routing behavior” would remedy that alternative situation, but it would not correct the present issue: an IPv4 /27 ordinarily has only thirty usable host addresses, so it cannot accommodate the stated phones and gateway.

“Reserve logical per-site prefixes within the /48, allocate appropriate /64 LANs and maintain documented room for subnets and future services” is the supported response when a flat random allocation from the /48 wastes the opportunity for site-level hierarchy and complicates growth and route summarization. Here the decisive response is “Allocate a suitably sized /25 or larger subnet after accounting for network, broadcast, gateway and expected device growth”, so that different intervention does not meet the stated requirement.

Randomly scattered branch subnets prevent region-level summarization and make routing and change control unnecessarily complex. “Reserve contiguous region-sized address blocks, allocate branch VLSM prefixes inside each block and summarize only reachable ranges at distribution boundaries” applies to that other condition. The reported evidence is a campus plans an ordinary IPv4 /27 for a voice VLAN with seventy active phones and expects enough usable addresses after adding a default gateway; this alternative would address the wrong dependency.