Cisco Updated 300-420 Exam Questions and Answers by malcolm

Locator/ID Separation Protocol is the control-plane technology that allows endpoint identity to be separated from endpoint location. In Cisco SD-Access, LISP is used by the fabric control plane to map endpoint identifiers to routing locators, so an endpoint subnet can remain logically consistent even when endpoint reachability is provided from different network locations. This is why LISP is associated with host mobility and with designs where the same subnet or endpoint identity can exist across multiple places without forcing the physical topology to be a single stretched Layer 2 domain. VXLAN is the data-plane encapsulation used to carry overlay traffic, but VXLAN itself is not the mapping control plane. FabricPath is a Cisco Layer 2 multipath technology and does not provide LISP-style endpoint-location mapping. ISE mobility services are identity and policy functions, not a routing locator mapping system. Therefore, the correct control-plane technology is LISP. Cisco SD-Access design material describes the control plane as the mapping system that maintains endpoint-to-device relationships.

The YANG module mapping follows the distinction between standards-based, vendor-neutral, and vendor-native data models. IETF YANG models are standards-driven and are appropriate when the design goal is protocol-level interoperability across vendors for common network functions. OpenConfig models are also vendor-neutral, but they are developed by the OpenConfig community and commonly use a structured separation between intended configuration and operational state. Cisco native models expose platform-specific Cisco IOS XE, IOS XR, or NX-OS capabilities and are often the most complete option when a feature is unique to a Cisco operating system. The selected drag-and-drop answer aligns each characteristic with the model family that owns that behavior. In a professional automation design, the engineer should not choose a model only because it is familiar. The correct choice depends on feature coverage, device support, platform release, schema stability, and whether the workflow must operate consistently across vendors. For multivendor intent, choose IETF or OpenConfig first; for Cisco-specific feature depth, use Cisco native models. Reference topics: YANG, IETF models, OpenConfig, Cisco native models, NETCONF and RESTCONF automation.

A distribute list is the correct method to filter routes exchanged between EIGRP neighbors within the same autonomous system. In Cisco EIGRP designs, distribute lists can be applied inbound or outbound under the EIGRP process to control which routes are accepted from or advertised to neighbors. The filter can reference an access list, prefix list, or route map depending on platform and configuration style. This allows the designer to limit route visibility without changing the forwarding behavior of packets that are already routed. Policy-based routing is a data-plane forwarding feature that changes next-hop selection for matching traffic; it does not filter EIGRP route advertisements between neighbors. Leak maps are used with route summarization to selectively advertise more specific routes through a summary, not as the general route-filtering method between EIGRP neighbors. Route tagging is valuable in redistribution designs to identify route origin and prevent feedback loops, but the tag alone does not filter routes unless a route map or distribute list uses it. Therefore, the correct route-filtering mechanism between EIGRP neighbors is a distribute list.

Spanning-tree PortFast must be enabled on interfaces where Wake-on-LAN clients reside so the PCs become reachable immediately when they power on. WoL depends on a sleeping endpoint receiving a magic packet, and once the device wakes, it must be able to send and receive traffic without waiting through traditional STP listening and learning states. Cisco campus designs commonly enable PortFast on access ports connected to end hosts so those ports transition directly to forwarding. That reduces login, DHCP, and application delays after a host becomes active. The NIC and system firmware must support WoL, but the option stating that WoL should be disabled in BIOS is technically wrong. IP directed broadcast and UDP forwarding are relevant when WoL packets must cross routed boundaries, but the answer options here focus on a single action to prevent client-side delay. Disabling directed broadcast or forward protocol would work against remote WoL operation. Reference topics: Wake-on-LAN, PortFast, access-layer design, STP edge ports, client startup convergence.