Cisco 300-420 Bundle

Policing enforces a rate by dropping or remarking excess packets, whereas shaping ordinarily smooths outbound bursts using buffers. “Document burst tolerance and discard implications when choosing policing or shaping for each class” would remedy that alternative situation, but it would not correct the present issue: a high-speed physical port does not imply equal committed service rate, so uncontrolled bursts can be discarded in the provider network.

“Audit QoS trust maps when onboarding new endpoint types or enabling unmanaged switch ports” is the supported response when trusting unvalidated endpoint DSCP markings allows unauthorized traffic to consume preferential network resources. Here the decisive response is “Revalidate shaping rates against provider CIR and accounting overhead after circuit or device changes”, so that different intervention does not meet the stated requirement.

An oversized or unbounded strict-priority queue can consume interface capacity and deny adequate service to other classes. “Review queue bandwidth guarantees and peak-rate policing as service demand changes” applies to that other condition. The reported evidence is a branch sends 1 Gbps bursts into an Ethernet handoff while its provider contract allows only 100 Mbps and drops excess traffic unpredictably; this alternative would address the wrong dependency.

That change concerns site to site vpn hub hairpin inspection, where Shortcut VPN topology changes can bypass required inspection if the WAN policy assumes every flow transits a central hub. The reported issue instead stems from: Service encapsulation consumes transport overhead and can exceed an underlay MTU that was sized only for native Ethernet payloads.

That change concerns wan backup route track to sla, where Local interface carrier may remain up when upstream service fails, so a static route without health tracking can blackhole traffic. In this question the necessary remedy is “Negotiate and implement supported provider service MTU and customer handoff frame sizes including encapsulation requirements”, which this alternative does not provide.

That change concerns single homed wan failure domain, where Multiple logical VLANs on the same physical CE and provider device do not provide independent failure domains. The observed condition is a provider delivers a Layer 2 VPN between sites with 1500-byte host payloads, but an extra service label and VLAN tag causes dropped frames in one segment; this mechanism addresses another problem.

Unfiltered inter-VRF route leaking can undermine segmentation even if each tenant has its own routing instance. “Export only authorized service prefixes and apply necessary packet access restrictions at the shared-services border” would remedy that alternative situation, but it would not correct the present issue: a summary advertised by a border without valid components can attract and blackhole traffic during partial network failures.

“Select a topology and route policy that maintain suitable symmetric inspected paths or supported state sharing” is the supported response when stateful inspection needs coherent bidirectional flow visibility, while independent routing cost choices can create asymmetric paths. Here the decisive response is “Tie aggregate advertisement to required downstream reachability or redesign summarization and redundancy accordingly”, so that different intervention does not meet the stated requirement.

High session counts and excessively aggressive timers can exhaust control resources and cause false routing flaps. “Model required convergence classes and scale BFD deployment selectively on critical routed interfaces” applies to that other condition. The reported evidence is two redundant campus borders advertise the same summary but only one border has reachability to the specific server block after an internal partition; this alternative would address the wrong dependency.

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” would remedy that alternative situation, but it would not correct the present issue: overlapping address spaces are ambiguous to ordinary destination-based routing and require unique addressing or deliberate translation boundaries.

“Reserve contiguous region-sized address blocks, allocate branch VLSM prefixes inside each block and summarize only reachable ranges at distribution boundaries” is the supported response when randomly scattered branch subnets prevent region-level summarization and make routing and change control unnecessarily complex. Here the decisive response is “Choose a phased renumbering design or carefully scoped NAT between the overlapping domains with clear DNS and application dependencies”, so that different intervention does not meet the stated requirement.

An IPv4 /27 ordinarily has only thirty usable host addresses, so it cannot accommodate the stated phones and gateway. “Allocate a suitably sized /25 or larger subnet after accounting for network, broadcast, gateway and expected device growth” applies to that other condition. The reported evidence is a newly acquired company uses 10.12.0.0/16, already used at headquarters, and an engineer proposes direct site-to-site routing between both unmodified networks; this alternative would address the wrong dependency.

Random early detection is usually better aligned with responsive TCP queues than with high-priority delay-sensitive voice traffic. “Use appropriate congestion avoidance on suitable best-effort TCP classes and protect voice through controlled priority service” would remedy that alternative situation, but it would not correct the present issue: encryption hides much application payload from intermediate classifiers, so deep packet inspection may not see per-app content inside the tunnel.

“Negotiate and implement DSCP-to-provider-CoS mapping and verify marking at each trust boundary” is the supported response when DSCP semantics and provider class-of-service mappings are not necessarily preserved across an independent administrative domain. Here the decisive response is “Classify and mark before encryption or use supported trusted tunnel metadata and policy-based identification at appropriate endpoints”, so that different intervention does not meet the stated requirement.

Priority queuing alone cannot create bandwidth beyond circuit capacity, and too many concurrent sessions can oversubscribe voice allocation. “Design call admission or session limits based on codec overhead and failover bandwidth, with controlled class policies” applies to that other condition. The reported evidence is an organization classifies applications by payload signatures inside IPsec tunnels and then finds all encrypted business traffic mapped to a single generic class; this alternative would address the wrong dependency.

That change concerns sd wan multicast design bandwidth cost, where Naive unicast replication can consume excessive WAN capacity, while multicast support depends on platform and overlay design. The reported issue instead stems from: An unsegmented overlay routing context can make trust-boundary errors more likely even if some edge access rules exist.

That change concerns sd wan regional scale and control topology, where Remote-only controller dependencies and insufficient regional capacity can degrade onboarding, resiliency and convergence at scale. In this question the necessary remedy is “Use separate service VPN or VRF contexts with explicit leak rules and security policy at authorized shared-service borders”, which this alternative does not provide.

That change concerns sd wan local internet breakout security, where Local breakout bypasses central inspection unless equivalent secure edge controls and policy are deliberately placed. The observed condition is guest Internet access and regulated internal branch traffic share one SD-WAN service VPN and use ordinary address filters for separation; this mechanism addresses another problem.

A single endpoint map/control-plane service is a common-mode availability risk even with redundant data-plane links. “Design supported control-plane node redundancy and test endpoint registration continuity during node loss” would remedy that alternative situation, but it would not correct the present issue: FHRP presence alone may not account for upstream path viability without appropriate object or interface tracking.

“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 “Track the required upstream path and decrement priority enough for a healthy standby gateway to assume forwarding”, so that different intervention does not meet the stated requirement.

FHRP peers must exchange control messages in a correctly shared VLAN to maintain a single active forwarding role. “Restore approved VLAN trunk reachability and compatible HSRP group and timer settings across both devices” applies to that other condition. The reported evidence is a campus HSRP active router loses its WAN uplink but keeps its local VLAN interface up, so users keep sending packets to a gateway that cannot exit the site; this alternative would address the wrong dependency.

Cloud service models allocate operational responsibility differently; consuming PaaS normally shifts underlying host management while retaining customer data and access duties. “Choose a suitable SaaS, PaaS or IaaS architecture with an explicit responsibility matrix for app, identity, runtime and infrastructure” would remedy that alternative situation, but it would not correct the present issue: TLS mutual authentication depends on valid identity and trust configuration, independent of basic network reachability.

“Design supported cloud on-ramp or cloud gateway integration with controlled routing, identity and service security policy” is the supported response when traditional centralized route topology can add delay and consume backbone capacity even when local cloud on-ramp options are available. Here the decisive response is “Deploy approved certificates and trust anchors for the telemetry endpoint and collector, including correct service identity names”, so that different intervention does not meet the stated requirement.

GNMI is a model-driven management interface commonly using gRPC streaming and structured path/value messages rather than a generic webpage. “Implement a supported gNMI client with secure gRPC connectivity and a valid Subscribe request for modeled paths” applies to that other condition. The reported evidence is a new telemetry collector can reach router TCP ports but the router refuses the gRPC session because the client and server certificate trust chains are not configured; this alternative would address the wrong dependency.

MST region membership requires consistent region identifier, revision and VLAN mapping rather than matching only some VLAN names. “Version MST configuration centrally and test cross-building changes before enabling additional VLANs” would remedy that alternative situation, but it would not correct the present issue: physical link-up is insufficient to guarantee bidirectional signal integrity, which can affect control-plane protocols and forwarding.

“Include VLAN-count forecasts in campus Layer 2 architecture capacity planning” is the supported response when a per-VLAN spanning-tree model scales protocol state with VLAN count and may become less efficient than suitable aggregated instances. Here the decisive response is “Include unidirectional-link testing in fiber plant acceptance and high-availability reviews”, so that different intervention does not meet the stated requirement.

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” applies to that other condition. The reported evidence is a duplex fiber campus uplink works in one direction but not the other, and interface carrier stays partially healthy while protocols behave unpredictably; this alternative would address the wrong dependency.

That change concerns campus transit acl route leak prevention, where Unfiltered inter-VRF route leaking can undermine segmentation even if each tenant has its own routing instance. The reported issue instead stems from: Physical redundancy does not imply control-plane equal-cost path installation or useful flow distribution.

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. In this question the necessary remedy is “Align appropriate IGP costs and supported equal-cost multipath settings with capacity and symmetric path requirements”, which this alternative does not provide.

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. The observed condition is two equal-bandwidth routed building uplinks are available but all flows pass one link because IGP costs and ECMP eligibility were not considered; this mechanism addresses another problem.

That change concerns network management vrf segmentation, where A common routing table broadens the management attack surface and increases risk of route or ACL leakage. The reported issue instead stems from: Independent rendezvous points do not automatically exchange all active-source information across ASM multicast domains.

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. In this question the necessary remedy is “Use supported MSDP or a suitable alternative interdomain multicast design with appropriate RP and source policies”, 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 two autonomous multicast domains each run PIM sparse mode with separate RPs, but receivers in one domain cannot discover active senders in the other; this mechanism addresses another problem.