Cisco 300-420 Bundle

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.

AS-path prepending mainly affects remote path selection; outbound path preference within the local AS is commonly controlled with local preference. “Set governed BGP local preference on inbound routes from the preferred provider, with consistent internal propagation” 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.

“Introduce redundant route reflectors with appropriate client hierarchy and loop-prevention identifiers” is the supported response when conventional iBGP full mesh grows quadratically and becomes costly to configure, observe and recover. Here the decisive response is “Use supported BGP MED where appropriate, coordinate the provider's comparison behavior and keep resilient alternate exits”, 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. “Apply approved outbound AS-path prepending on the less-preferred transit and check provider acceptance and alternate routing” 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.

Unbounded EIGRP query scope and nontransit spokes can prolong active route computation across a large topology. “Declare eligible nontransit branches as EIGRP stubs and summarize at appropriate aggregation points with verified alternate paths” would remedy that alternative situation, but it would not correct the present issue: protocol adjacency and IPv4 routes do not alone establish correct IPv6 reachability, interface addressing or address-family support.

“Deploy supported IS-IS authentication with coordinated algorithms and keys and restrict peers to intended segments” is the supported response when an unprotected adjacency trust boundary can admit unauthorized IS-IS control messages into a routing domain. Here the decisive response is “Implement supported IS-IS IPv6 reachability with interface family configuration and consistent topology preferences”, so that different intervention does not meet the stated requirement.

Mixed or unsuitable metric styles can undermine consistent path-cost planning and overflow the intended metric range. “Standardize supported wide-metric design and audit interface cost policies across participating IS-IS devices” applies to that other condition. The reported evidence is a network has existing IS-IS IPv4 reachability and adds IPv6-only applications, but the design assumes IPv4 reachability automatically creates IPv6 forwarding information; this alternative would address the wrong dependency.

That change concerns qos validation with actual queue counters, where A syntactically installed QoS policy does not establish that actual applications match intended classes or receive required forwarding treatment. The reported issue instead stems from: Traffic classification order and policy constructs can cause broad conditions to overshadow intended more-specific class handling.

That change concerns qos oversubscription during backup, where Policy percentages alone do not preserve service if critical aggregate traffic exceeds reduced failover link capacity. In this question the necessary remedy is “Refine class-map criteria and supported policy evaluation to classify the real-time flows before generic groups”, which this alternative does not provide.

That change concerns video traffic burst and jitter buffer design, where Average throughput can hide instantaneous bursts and delay variation that disrupt real-time media even when link utilization seems moderate. The observed condition is a provider WAN policy places a broad match-any business group before a specific real-time collaboration class, so important voice traffic gets generic treatment; this mechanism addresses another problem.

AS-path prepending mainly affects remote path selection; outbound path preference within the local AS is commonly controlled with local preference. “Set governed BGP local preference on inbound routes from the preferred provider, with consistent internal propagation” would remedy that alternative situation, but it would not correct the present issue: IBGP typically preserves the external next hop, which must be reachable through the internal routing infrastructure.

“Apply approved outbound AS-path prepending on the less-preferred transit and check provider acceptance and alternate routing” is the supported response when local preference is not exported between autonomous systems, so changing it cannot directly govern external networks' inbound selection. Here the decisive response is “Provide appropriate next-hop-self policy or valid internal reachability for external BGP next hops with loop-free forwarding”, so that different intervention does not meet the stated requirement.

Internal OSPF cost does not communicate an intended interconnect preference to the neighboring autonomous system. “Use supported BGP MED where appropriate, coordinate the provider's comparison behavior and keep resilient alternate exits” applies to that other condition. The reported evidence is an edge router shares eBGP-learned routes with internal iBGP peers, but remote clients cannot resolve the unchanged external next-hop address; this alternative would address the wrong dependency.

Trusting unvalidated endpoint DSCP markings allows unauthorized traffic to consume preferential network resources. “Define an appropriate trust boundary and classify or remark traffic at access based on authenticated application and endpoint context” would remedy that alternative situation, but it would not correct the present issue: an oversized or unbounded strict-priority queue can consume interface capacity and deny adequate service to other classes.

“Choose a scalable DiffServ class-based policy where application requirements permit, reserving per-flow mechanisms for justified domains” is the supported response when per-flow IntServ state scales differently from aggregated DiffServ classes and can become operationally expensive for large multi-site deployments. Here the decisive response is “Reserve low-latency priority treatment for justified real-time traffic with controlled bandwidth and balanced class allocations”, so that different intervention does not meet the stated requirement.

Policing enforces a rate by dropping or remarking excess packets, whereas shaping ordinarily smooths outbound bursts using buffers. “Use shaping for traffic that can tolerate buffering and selective policing where a hard ingress contract is needed” applies to that other condition. The reported evidence is an enterprise places voice, video, backups and database replication in one strict-priority class, and ordinary business applications starve during a site backup; this alternative would address the wrong dependency.

OSPF hierarchical inter-area connectivity depends on a stable backbone design and resilient area border connectivity. “Design redundant ABRs with valid backbone area connectivity and deterministic cost preferences for inter-area paths” would remedy that alternative situation, but it would not correct the present issue: a normal area floods external routing information that stub-capable branches may not need when a default route is sufficient.

“Allocate summarizable ranges and apply appropriate ABR area range configuration with complete component-route validation” is the supported response when a fragmented area-address plan and missing ABR inter-area summarization cause avoidable detailed LSAs to propagate. Here the decisive response is “Choose a supported stub-area design consistently across the area and ensure the ABR provides an appropriate default route”, 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 a branch OSPF area has no external-route ASBR but receives unnecessary external LSAs from the backbone and has constrained router memory; this alternative would address the wrong dependency.

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: a /15 covers two consecutive aligned /16 networks and the selected /15 omits 10.66.0.0/16 while including unintended space.

“Allocate a suitably sized /25 or larger subnet after accounting for network, broadcast, gateway and expected device growth” is the supported response when an IPv4 /27 ordinarily has only thirty usable host addresses, so it cannot accommodate the stated phones and gateway. Here the decisive response is “Create aligned aggregates that cover actual component prefixes and validate binary prefix boundaries and the destination routing behavior”, so that different intervention does not meet the stated requirement.

A flat random allocation from the /48 wastes the opportunity for site-level hierarchy and complicates growth and route summarization. “Reserve logical per-site prefixes within the /48, allocate appropriate /64 LANs and maintain documented room for subnets and future services” applies to that other condition. The reported evidence is an engineer advertises 10.64.0.0/15 to summarize 10.64.0.0/16 and 10.66.0.0/16, causing traffic for one site to be routed outside its intended aggregation boundary; this alternative would address the wrong dependency.

An encrypted Internet overlay does not provide the same private carrier connectivity, SLA and traffic-engineering options as a qualified dedicated cloud circuit. “Compare direct cloud private interconnect with managed Internet VPN based on security, bandwidth, route exchange and service commitments” would remedy that alternative situation, but it would not correct the present issue: logical dual-circuit contracts may share a physical access path and suffer a common-cause outage.

“Use a supported DMVPN phase and NHRP routing design that safely establishes eligible spoke-to-spoke tunnels” is the supported response when a purely hub-and-spoke forwarding policy can add latency and load when the DMVPN design is intended to allow direct spoke shortcuts. Here the decisive response is “Choose WAN edge circuits with validated last-mile, provider and facility diversity where the service recovery target requires it”, 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 branch selects two MPLS circuits from the same provider that terminate in one local trench and claims the resulting design is carrier diverse; this alternative would address the wrong dependency.

Conventional iBGP full mesh grows quadratically and becomes costly to configure, observe and recover. “Introduce redundant route reflectors with appropriate client hierarchy and loop-prevention identifiers” 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.

“Use supported point-to-point OSPF network type consistently on both sides where the physical design permits” is the supported response when default broadcast OSPF network behavior can elect designated routers even when the topology is only a two-router link. 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.

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 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.

An IPv4-only underlay cannot natively carry IPv6 forwarding without an overlay or other transition capability. “Use a supported IPv6-over-IPv4 tunnel with correct endpoint reachability, encapsulation security and effective MTU” 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.

“Evaluate path attributes and supported multipath settings, then choose a design that preserves deterministic failover” is the supported response when BGP additional paths must satisfy supported multipath eligibility rules and configured maximum-path policy to share traffic. Here the decisive response is “Choose an aggregate policy with reviewed component-route dependencies, conservative discard behavior and correct reachability design”, 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. “Enable and verify supported graceful restart with sensible stale timers and failover safeguards where appropriate” 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.