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

The design must influence how EIGRP-learned routes are injected into the OSPF domain, so R2 should redistribute EIGRP into OSPF as metric-type E1 and R3 as metric-type E2. Cisco OSPF documentation distinguishes external Type 1 and Type 2 routes. An E1 route includes the external cost plus the internal OSPF cost to reach the ASBR, while an E2 route uses only the external metric. Cisco path selection prefers O E1 over O E2 for the same external destination. Therefore, making R2 advertise the EIGRP routes as E1 causes OSPF routers to prefer R2 as the exit toward the EIGRP domain. Option C adjusts OSPF-to-EIGRP redistribution, which is the wrong direction for traffic passing toward EIGRP from OSPF. Removing redistribution on R3 would reduce redundancy. Option D reverses the preference and would favor R3. Reference topics: OSPF external route types, EIGRP-to-OSPF redistribution, ASBR preference, E1 versus E2 metrics.

The vSmart controller provides the centralized control plane in a Cisco SD-WAN deployment. It establishes secure control connections with WAN Edge routers and exchanges routing, topology, security, and policy information using OMP. The vSmart controller does not forward user data traffic; data-plane forwarding occurs directly between WAN Edge routers over IPsec or other supported encapsulations. Its function is to distribute reachability information, TLOC information, service routes, centralized policies, application-aware routing policies, and segmentation information that determines how the overlay operates. vBond orchestrates onboarding, authentication facilitation, and NAT traversal for control connections. vManage provides centralized management, monitoring, configuration templates, and operational GUI/API functions. vEdge or Cisco IOS XE SD-WAN routers provide the branch or site data plane and local routing functions. Therefore, among the choices, the vSmart controller is responsible for the centralized control plane of the SD-WAN network. Correctly separating orchestration, management, control, and data-plane roles is a core Cisco SD-WAN design principle.

Root guard is the correct feature when the design must allow switches to be attached for testing but prevent those switches from influencing the spanning-tree root placement. Cisco root guard protects the intended STP root by placing a port into a root-inconsistent state if superior BPDUs are received on a port where the root should never appear. This directly addresses the risk created by rogue or lab switches connected by end users: if a user switch advertises a better bridge priority, the production access topology is not allowed to reconverge around that unauthorized device. BPDU guard is usually used on PortFast edge ports to err-disable a port that receives any BPDU, which is excellent for strict host-only ports but less aligned with the wording that users may connect their own switches for testing. Loop guard protects root or alternate ports from losing BPDUs and accidentally forwarding. BPDU skew detection is a diagnostic feature, not the correct design control. Therefore, root guard is the appropriate protection against rogue switches affecting STP topology. Reference topics: STP root placement, root guard, superior BPDUs, campus Layer 2 protection.