300-420 Exam Dumps - Designing Cisco Enterprise Networks (ENSLD) v1.1

The control-plane node in Cisco SD-Access acts as the map system that manages endpoint-to-device relationships. Cisco SD-Access documentation describes control-plane nodes as maintaining the host database that maps endpoint identifiers to the fabric edge devices where those endpoints are attached. This mapping function is based on LISP control-plane behavior. When an endpoint appears on an edge node, the edge registers the endpoint information with the control plane. When another fabric device needs to send traffic to that endpoint, it queries the control-plane node to resolve the endpoint location. A fabric edge node is the device that connects wired endpoints to the fabric, so option A describes an edge role. Wireless endpoints may attach through fabric AP and fabric WLC integration, but that is not the control-plane node’s role. External Layer 3 networks are connected through border nodes, not through the control-plane node. Therefore, the correct role is endpoint-to-device mapping. Accurate control-plane design is essential for fabric scale, endpoint mobility, and fast location resolution.

The correct choice is to use a distribute list outbound under the RIP process to stop EIGRP-learned prefixes from being advertised back into the RIP domain. In multipoint two-way redistribution, the major risk is route feedback: a route learned from one protocol is redistributed into another protocol and then reintroduced back into the original domain through another redistribution point. RIPv1 is especially limited because it is classful and has no native route tagging, so filtering must be carefully placed when route tags are unavailable. By filtering outbound advertisements under the RIP process, the design prevents routes that originated in the EIGRP domain from being sent into RIP where they could be relearned elsewhere and create loops or suboptimal paths. Inbound filtering on only one process does not reliably stop feedback at all redistribution points. A stronger modern design would use route tags with protocols that support them, but given the answer choices, outbound filtering toward RIP is the appropriate loop-prevention method. Reference topics: route redistribution, distribute lists, route feedback, RIPv1 limitations, EIGRP integration.

Cisco Catalyst SD-WAN Cloud OnRamp is built to simplify and automate cloud connectivity from enterprise sites. Cisco describes the feature as a way to simplify connecting on-premises environments to cloud-hosted applications and workloads while extending SD-WAN policy into the cloud. The key design value is automation: branches and data centers can connect to SaaS, IaaS, or multicloud resources without manually building every tunnel, route policy, and cloud attachment. That is why option D is the strongest answer. Option A is too broad because generic transport independence is a core SD-WAN value, not the specific purpose of Cloud OnRamp. Option B confuses Cloud OnRamp with application-aware routing policy. Option C describes a business outcome, but the operational purpose tested here is automated on-premises-to-cloud integration and consistent policy extension. Reference topics: Cisco Catalyst SD-WAN Cloud OnRamp, multicloud connectivity, cloud workload access, SD-WAN fabric extension, automated cloud onboarding.

The correct design uses IPv4 unicast for Company A and Company B and VPNv4 in the shared core. In an MPLS Layer 3 VPN architecture, customer edge routing toward the provider edge commonly uses the ordinary IPv4 unicast address family. The PE router then places the learned customer routes into the appropriate VRF. Across the shared provider core, MP-BGP carries those customer routes as VPNv4 prefixes by adding route distinguishers, which keep identical or overlapping customer prefixes unique. Route targets then control which VRFs import or export each route. Cisco describes this VRF and VPNv4 model as the mechanism that prevents one VPN customer from learning another customer’s prefixes while sharing the same provider backbone. VPNv4 is not normally used directly between the customer networks and their CE-facing sessions. Therefore, the customer sides use IPv4 unicast, and the shared core uses VPNv4 to preserve separation. Reference topics: MPLS Layer 3 VPN, MP-BGP VPNv4, VRF, route distinguisher, route targets, customer route isolation.

Cisco Express Forwarding uses the adjacency table to store the Layer 2 rewrite information needed to forward packets efficiently. CEF separates forwarding decisions into the Forwarding Information Base and the adjacency table. The FIB identifies the best next hop based on routing information, while the adjacency table contains the directly connected next-hop details, including the MAC address and encapsulation rewrite string used on the outgoing interface. That is why the correct layer is Layer 2. CEF is not using the adjacency table to populate Layer 3 routes; the routing table and FIB handle Layer 3 reachability. It is also not a Layer 1 function because physical signaling does not determine the next-hop rewrite. Layer 4 is unrelated to CEF adjacency resolution. In a campus or WAN design, CEF matters because it allows hardware or optimized software forwarding without process-switching every packet. Correct ARP, neighbor discovery, and adjacency formation are therefore essential to fast packet forwarding, especially when convergence or high-throughput forwarding is required.

The correct policy is to prepend the AS path on the nonpreferred advertisement for each prefix. For inbound BGP traffic engineering, the enterprise normally influences remote autonomous systems by changing attributes that those systems see when selecting a path. AS-path prepending makes a route appear less attractive by adding repeated instances of the local AS number to the AS path. In this design, network 10.1.1.0/24 should enter through R3-R1, so R2 must advertise that prefix with a prepended AS path to make the R4-R2 path less preferred unless the primary path fails. Conversely, network 10.1.2.0/24 should enter through R4-R2, so R1 must advertise that prefix with prepending to make the R3-R1 path less preferred. This creates inbound load sharing while preserving failover because the prepended route remains available as a backup. Local preference affects outbound path selection inside the local AS, not inbound selection by the provider. Reference topics: BGP traffic engineering, AS-path prepending, inbound path control, prefix-specific policy, multihomed WAN design.

Affinity is the SD-WAN feature used to control and reduce control connections between WAN Edge devices and vSmart controllers. Cisco SD-WAN high-availability documentation describes controller affinity as a way to limit the number of controllers that an edge device establishes control connections with, while still preserving controller and data center redundancy. This reduces unnecessary control-plane load and limits the strain placed on vSmart controllers in large overlays. The feature is particularly useful when multiple vSmart controllers exist across multiple data centers and the designer wants predictable primary and backup controller relationships. The color attribute identifies transport characteristics, such as public Internet, MPLS, or other transport types. Control-connections is a general concept, not the feature that minimizes them. Control-direction is not the correct design construct for this purpose. A scalable SD-WAN design should use affinity where controller scale, regionalization, and control-plane efficiency must be explicitly managed. Reference topics: Cisco SD-WAN controller affinity, vSmart scale, control connections, TLOC control-plane optimization.

An inbound IP prefix list is the correct tool because the routers must decide which prefixes to accept from the service provider based only on prefix length. Prefix lists are designed to match network prefixes and mask-length ranges using operators such as le and ge. Applying the prefix list inbound to the BGP neighbors prevents routes with masks longer than /24 from entering the local BGP table, regardless of what the service provider advertises. This conserves memory and ensures the customer routing policy is enforced locally. An access list is a poor fit because it does not natively express prefix-length logic as cleanly as a prefix list. Applying the policy outbound would filter routes the customer sends to the provider, which is the wrong direction; the requirement is about routes the customer learns. A route map could reference a prefix list, but the simplest and most exact answer is to use an IP prefix list inbound. Therefore, the design should apply an inbound prefix list to both BGP peers to block prefixes greater than /24. Reference topics: BGP route filtering, prefix lists, inbound policy, maximum accepted prefix length.