Cisco 300-420 Bundle

That change concerns eigrp unequal cost traffic sharing, where EIGRP unequal-cost load sharing is not enabled simply because multiple routes exist and is constrained by feasibility and variance. The reported issue instead stems from: Uncontrolled bidirectional redistribution can reintroduce routes, create loops and lose source-of-truth route preference.

That change concerns eigrp feasible successor requirements, where An EIGRP feasible successor must satisfy its feasibility condition relative to the successor's feasible distance to prevent loops. In this question the necessary remedy is “Use explicit tag-based redistribution policy, defined metrics and directional filters at well-documented borders”, which this alternative does not provide.

That change concerns eigrp authentication mismatched key chain, where Neighbor authentication parameters and permitted key windows must align or the routing protocol rejects peer messages. The observed condition is two autonomous branch EIGRP routing domains redistribute into one core and begin sending learned routes back into the origin domain; this mechanism addresses another problem.

IP reachability does not imply that IKE versions, cryptographic proposals, identities and authentication settings agree across peers. “Track cryptographic algorithm and lifetime standards jointly across every VPN peer lifecycle” would remedy that alternative situation, but it would not correct the present issue: multipoint Ethernet services and many independent E-Line circuits have different Layer 2 forwarding and spanning-tree implications.

“Verify seasonal radio performance and data-cap alarms before relying on cellular as a branch recovery path” is the supported response when mobile backup is useful only if real coverage, policy, cost and failure independence support required branch services. Here the decisive response is “Document E-Line versus E-LAN service boundaries and operational responsibility with the provider”, so that different intervention does not meet the stated requirement.

An MPLS Layer 3 VPN routes IP among separated CE networks rather than delivering a transparent Layer 2 Ethernet service. “Assess broadcast extension failure domains before buying a transparent transport solely to avoid route design” applies to that other condition. The reported evidence 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 alternative would address the wrong dependency.

A hybrid deployment can transfer sensitive data or metadata across administrative and geographic boundaries even when application compute stays on-premises. “Design controlled hybrid data flow, regional placement and access policies that satisfy residency and connectivity requirements” would remedy that alternative situation, but it would not correct the present issue: cloud service models allocate operational responsibility differently; consuming PaaS normally shifts underlying host management while retaining customer data and access duties.

“Prefer a suitable standards-based IETF model for portable interface telemetry, documenting implementation gaps and vendor extensions” is the supported response when vendor-native data models may expose platform-specific schema that cannot be queried identically across different vendors. Here the decisive response is “Choose a suitable SaaS, PaaS or IaaS architecture with an explicit responsibility matrix for app, identity, runtime and infrastructure”, so that different intervention does not meet the stated requirement.

Private transport does not automatically enforce tenant segmentation or prevent unintended route exchange into cloud environments. “Integrate MPLS L3VPN with approved cloud private routing and select per-tenant VRF and gateway route policies” applies to that other condition. The reported evidence 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 alternative would address the wrong dependency.

That change concerns ospf stub area external lsa control, where A normal area floods external routing information that stub-capable branches may not need when a default route is sufficient. The reported issue instead stems from: Overlay headers reduce usable path MTU and blocked ICMPv6 Packet Too Big feedback can prevent Path MTU Discovery.

That change concerns ipv6 security policy parity, where IPv4-only security rules do not automatically enforce the same trust boundary for IPv6 traffic on a dual-stack path. In this question the necessary remedy is “Budget tunnel overhead in MTU planning, preserve required ICMPv6 control messages and validate endpoints' segment sizes”, which this alternative does not provide.

That change concerns nat64 dns64 ipv6-only application access, where IPv6-only clients cannot communicate with IPv4-only services without supported translation and suitable destination synthesis. The observed condition is a dual-stack application works with small IPv6 probes through a GRE overlay but stalls on larger encrypted payloads after tunnel encapsulation; this mechanism addresses another problem.

An oversized or unbounded strict-priority queue can consume interface capacity and deny adequate service to other classes. “Reserve low-latency priority treatment for justified real-time traffic with controlled bandwidth and balanced class allocations” would remedy that alternative situation, but it would not correct the present issue: trusting unvalidated endpoint DSCP markings allows unauthorized traffic to consume preferential network resources.

“Shape outbound traffic to a suitable rate below the provider policer and apply useful internal priority queues” is the supported response when a high-speed physical port does not imply equal committed service rate, so uncontrolled bursts can be discarded in the provider network. Here the decisive response is “Define an appropriate trust boundary and classify or remark traffic at access based on authenticated application and endpoint context”, so that different intervention does not meet the stated requirement.

Per-flow IntServ state scales differently from aggregated DiffServ classes and can become operationally expensive for large multi-site deployments. “Choose a scalable DiffServ class-based policy where application requirements permit, reserving per-flow mechanisms for justified domains” applies to that other condition. The reported evidence is a user-controlled workstation marks all outbound bulk backup packets as expedited forwarding, causing voice queues to saturate during office hours; this alternative would address the wrong dependency.

A hybrid WAN needs explicit route and security decisions because reachability alone does not guarantee sensitive traffic uses approved paths. “Classify traffic by trust and business criticality and apply supported routing or SD-WAN policies for each transport” would remedy that alternative situation, but it would not correct the present issue: bandwidth alone does not determine application suitability when propagation delay and jitter exceed interactive service limits.

“Design consistent BGP advertisement, NAT and routing failover so return flows follow the reachable secondary path” is the supported response when multihoming and address translation must account for both directions; outbound route changes alone may not preserve return paths. Here the decisive response is “Choose appropriate low-latency WAN transport and QoS treatment, evaluating cost, resilience and route diversity”, so that different intervention does not meet the stated requirement.

N-minus-one operation cannot carry combined load if each remaining link lacks spare capacity or business traffic prioritization. “Size redundant WAN capacity for failure-state critical loads or design explicit congestion and traffic-class degradation policy” applies to that other condition. The reported evidence is a global contact center selects a very high bandwidth satellite transport for real-time voice even though round-trip latency dominates the application impairment; 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. “Perform overlap detection in IPAM during mergers and document all temporary translation rules and decommissioning milestones” would remedy that alternative situation, but it would not correct the present issue: randomly scattered branch subnets prevent region-level summarization and make routing and change control unnecessarily complex.

“Maintain an IPv6 hierarchy registry and consistently reserve site and functional subnet identifiers before provisioning” 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 “Use an authoritative IP address management registry with reservation, collision checks and explicit aggregation ownership for new sites”, 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. “Include realistic utilization forecasts and host-capacity arithmetic in IP addressing design signoff rather than relying on prefix labels” applies to that other condition. The reported evidence is a company has thirty branches that each receive random /24 networks from a central /16. It needs regional route aggregation, predictable expansion and simpler access policies without renumbering annually; this alternative would address the wrong dependency.

Independent rendezvous points do not automatically exchange all active-source information across ASM multicast domains. “Use supported MSDP or a suitable alternative interdomain multicast design with appropriate RP and source policies” would remedy that alternative situation, but it would not correct the present issue: ASM shared-tree setup may depend on reachable RP control functions that need deliberate redundancy.

“Select telemetry collection intervals and methods proportional to observed change rates and device capacity” is the supported response when overly aggressive polling can consume limited control-plane CPU and management bandwidth without improving decision quality. Here the decisive response is “Design supported redundant RP mechanisms with consistent group mappings and reachability across the multicast domain”, so that different intervention does not meet the stated requirement.

Central monitoring infrastructure can become a single point of failure even when individual access devices have redundant uplinks. “Design appropriate collector and transport redundancy with supported failover and secure retention behavior” applies to that other condition. The reported evidence is a campus deploys PIM sparse mode ASM with one rendezvous point and loses new receiver joins whenever that RP router is unavailable; 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: a /15 covers two consecutive aligned /16 networks and the selected /15 omits 10.66.0.0/16 while including unintended space.

“Choose a phased renumbering design or carefully scoped NAT between the overlapping domains with clear DNS and application dependencies” is the supported response when overlapping address spaces are ambiguous to ordinary destination-based routing and require unique addressing or deliberate translation boundaries. 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.

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 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.

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 reported issue instead stems from: Bidirectional multipoint redistribution without route tagging or authoritative direction can reintroduce routes into their source protocol.

That change concerns campus distributed layer 3 access, where Extending Layer 2 broadly across campus buildings increases loop, convergence and failure-domain exposure. In this question the necessary remedy is “Apply explicit redistribution filters, tags, metrics and domain ownership at each boundary with deliberate failure fallback”, which this alternative does not provide.

That change concerns multicampus route summarization boundary, where Missing site-level address summarization increases routing state and exposes the WAN to local campus topology churn. The observed condition is two campus cores exchange OSPF and EIGRP routes across two border routers and route entries recirculate until suboptimal paths appear; this mechanism addresses another problem.

Stateful inspection needs coherent bidirectional flow visibility, while independent routing cost choices can create asymmetric paths. “Include reverse-path verification in campus security zone design and ECMP changes” 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.

“Establish timer and session-count budgets per platform before promising uniform subsecond convergence” is the supported response when high session counts and excessively aggressive timers can exhaust control resources and cause false routing flaps. Here the decisive response is “Test partial reachability failures, not only complete router outages, when validating multicampus route policy”, so that different intervention does not meet the stated requirement.

Unfiltered inter-VRF route leaking can undermine segmentation even if each tenant has its own routing instance. “Audit shared services route leaks and ACLs together after each tenant or service onboarding” 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.