Cisco 300-420 Bundle

That change concerns pim sparse mode receiver path joins, where PIM sparse mode forwarding relies on supported multicast routing and receiver membership along the required multicast distribution tree. The reported issue instead stems from: Without class-based queue service, different traffic priorities may compete equally under congestion rather than receiving guaranteed minimum allocations.

That change concerns qos remarking across carrier boundary, where DSCP semantics and provider class-of-service mappings are not necessarily preserved across an independent administrative domain. In this question the necessary remedy is “Implement appropriate CBWFQ or platform-supported scheduler weights after classifying actual traffic”, which this alternative does not provide.

That change concerns qos classification encrypted traffic, where Encryption hides much application payload from intermediate classifiers, so deep packet inspection may not see per-app content inside the tunnel. The observed condition is a WAN link has three business traffic classes but the design uses only a best-effort FIFO queue, creating unpredictable delay during peaks; 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: encapsulation and encryption overhead reduce effective path MTU, and missing PMTUD control messages can stall large packets.

“Treat key server redundancy, rekey windows and group membership security as critical design dependencies” is the supported response when traditional point-to-point encryption tunnel meshes may add unnecessary topology and scale complexity for a trusted private routed underlay. Here the decisive response is “Include maximum-frame and PMTU tests in every overlay transport acceptance plan”, so that different intervention does not meet the stated requirement.

VPN session status can be healthy while mismatched crypto ACLs or traffic selectors omit the application flow. “Reconcile cloud subnet additions with tunnel selectors and routing changes before declaring VPN rollout complete” applies to that other condition. The reported evidence is a branch adds GRE over IPsec and experiences intermittent large-file transfer failures even though small test pings work; 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: a common routing instance cannot enforce independent overlapping IP destinations and controlled route exposure by itself.

“Design supported VACL, private VLAN or separate VLAN segmentation according to local traffic patterns and platform capabilities” is the supported response when an SVI routed ACL does not necessarily inspect intra-VLAN switched frames that never reach Layer 3 forwarding. Here the decisive response is “Design supported VRF-lite routing instances with carefully governed shared-services connectivity and separate interface assignments”, so that different intervention does not meet the stated requirement.

Missing site-level address summarization increases routing state and exposes the WAN to local campus topology churn. “Plan contiguous campus address blocks and advertise valid site summaries at L3 distribution or WAN boundaries” applies to that other condition. The reported evidence is guest kiosks and regulated finance terminals share one campus routing table despite requirements that their overlapping address blocks remain isolated; this alternative would address the wrong dependency.

Shortcut VPN topology changes can bypass required inspection if the WAN policy assumes every flow transits a central hub. “Use a security-enforcing hub design or distributed inspection architecture with explicit policy for branch-to-branch traffic” would remedy that alternative situation, but it would not correct the present issue: uncontrolled multihoming can select unpredictable exits and cause asymmetry or suboptimal paths under provider changes.

“Design separate CE devices, access paths and service-provider terminations in accordance with the required availability objective” is the supported response when multiple logical VLANs on the same physical CE and provider device do not provide independent failure domains. Here the decisive response is “Define local preference, inbound announcement policy and health tracking based on primary and backup business requirements”, so that different intervention does not meet the stated requirement.

Service encapsulation consumes transport overhead and can exceed an underlay MTU that was sized only for native Ethernet payloads. “Negotiate and implement supported provider service MTU and customer handoff frame sizes including encapsulation requirements” applies to that other condition. The reported evidence is an enterprise connects to two providers and wants symmetric business traffic behavior but simply allows both defaults with no designed routing policies; this alternative would address the wrong dependency.

That change concerns cisco sd wan transport tloc diversity, where Logical transport labels or TLOCs do not inherently represent independent circuits, carrier facilities or last-mile paths. The reported issue instead stems from: Logical dual-circuit contracts may share a physical access path and suffer a common-cause outage.

That change concerns ipsec encryption versus gre transport, where GRE provides encapsulation for multiple protocols but does not itself encrypt or authenticate payload confidentiality. In this question the necessary remedy is “Choose WAN edge circuits with validated last-mile, provider and facility diversity where the service recovery target requires it”, which this alternative does not provide.

That change concerns dmvpn spoke to spoke optimization, where A purely hub-and-spoke forwarding policy can add latency and load when the DMVPN design is intended to allow direct spoke shortcuts. The observed condition 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 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.

“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 “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.

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 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.

That change concerns multicast source rpf under ecmp, where Multicast RPF decisions can be sensitive to unicast path selection, including ECMP and asymmetric routing behavior. The reported issue instead stems from: PIM sparse mode forwarding relies on supported multicast routing and receiver membership along the required multicast distribution tree.

That change concerns multicast boundary group filtering, where Without explicit multicast boundary control, group advertisements or forwarding may extend beyond authorized trust domains. In this question the necessary remedy is “Enable appropriate PIM and IGMP behavior on intended routed interfaces and validate RP and RPF reachability”, which this alternative does not provide.

That change concerns multicast scaling versus replicated unicast, where Naive replicated unicast can consume far more shared-link capacity than a suitable multicast tree for many receivers. The observed condition is a multicast stream is sourced at headquarters but branch routers never send joins for newly subscribed remote receivers, despite working unicast tunnels; this mechanism addresses another problem.

That change concerns metro ethernet multi site scaling, where Multipoint Ethernet services and many independent E-Line circuits have different Layer 2 forwarding and spanning-tree implications. The reported issue instead stems from: A shared provider routing domain cannot preserve independent overlapping tenant address spaces and route targets without isolation.

That change concerns cellular 4g 5g branch backup, where Mobile backup is useful only if real coverage, policy, cost and failure independence support required branch services. In this question the necessary remedy is “Select a supported MPLS L3VPN design using separate VPN routing tables and approved route-target import/export policy”, which this alternative does not provide.

That change concerns dwdm optical backbone capacity, where Ordinary port-level upgrades may not meet aggregate fiber-capacity and distance requirements when the optical transport must host many independent wavelengths. The observed condition is an enterprise has many branch customers with overlapping private prefixes and proposes one shared provider IP routing instance for all tenants; this mechanism addresses another problem.

That change concerns is-is level 1 and level 2 area topology, where IS-IS Level 1 operates within an area while Level 2 provides inter-area connectivity and should bound unwanted topology flooding. The reported issue instead stems from: Premature use of a partially ready intermediate system can blackhole transit despite apparently formed control-plane neighbors.

That change concerns ipv6 ula versus global addressing design, where Provider-dependent global prefixes may require renumbering when upstream connectivity changes and do not replace a stable local-only design. In this question the necessary remedy is “Use a supported startup overload-bit or similar transient-transit suppression design until the node is ready to forward”, which this alternative does not provide.

That change concerns ipv6 subnet prefix length on end-user lan, where Typical Ethernet SLAAC uses /64 interface identifiers and ordinary host autoconfiguration expectations are not met by arbitrary longer access prefixes. The observed condition is a router with IS-IS adjacencies comes back after reboot before its forwarding resources and external routes finish loading, but its neighbors immediately use it as a transit node; this mechanism addresses another problem.

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: 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.

Secure SD-WAN fabric admission requires authorized organization identifiers and valid identity trust, not just IP routing. “Design approved CA trust, certificate lifecycle and device authorization procedures for every control node and edge” would remedy that alternative situation, but it would not correct the present issue: static transport preference does not substitute for application-aware path decisions using measured latency, loss and jitter.

“Design approved branch egress security with local firewall, cloud security service or appropriate service chaining” is the supported response when local breakout bypasses central inspection unless equivalent secure edge controls and policy are deliberately placed. Here the decisive response is “Create supported application-aware routing policy with validated SLA class thresholds and fallback behavior”, so that different intervention does not meet the stated requirement.

An unsegmented overlay routing context can make trust-boundary errors more likely even if some edge access rules exist. “Use separate service VPN or VRF contexts with explicit leak rules and security policy at authorized shared-service borders” applies to that other condition. The reported evidence is a voice collaboration app takes the least-cost broadband transport even when packet loss breaches an SLA because policy only prefers link color and ignores live performance; this alternative would address the wrong dependency.