300-420 Exam Dumps : Designing Cisco Enterprise Networks

The selected design is correct because the requirement describes a resilient campus architecture that must support the same VXLAN at any access-layer switch while maintaining fast convergence and high availability. In Cisco campus and data-center-style fabric designs, VXLAN provides network virtualization by carrying Layer 2 adjacency over a routed or resilient transport. The correct design must avoid a fragile single spanning-tree domain and must provide redundant forwarding paths so that an access switch or uplink failure does not isolate the VLAN or VXLAN segment. The selected option represents the design that meets those conditions by allowing the overlay segment to be extended consistently across access switches while keeping the underlay resilient. Designs that rely on a traditional Layer 2 tree, a single aggregation point, or blocked redundant links would not meet the high availability and fast convergence objectives. The important design principle is that VXLAN should ride on a stable, redundant transport and should not depend on large Layer 2 failure domains. Reference topics: VXLAN campus design, overlay networking, fast convergence, access-layer resiliency, high availability.

NETCONF supports XML, while RESTCONF supports both XML and JSON. Cisco programmability documentation describes NETCONF as an XML-based protocol that exchanges RPC requests and replies such as get, get-config, and edit-config using XML encoding. NETCONF is tightly aligned with YANG-modeled data, but the protocol message format itself is XML. RESTCONF exposes YANG-modeled data through an HTTP or HTTPS API and can represent payloads in XML or JSON. Cisco DevNet material commonly summarizes the comparison as NETCONF equals XML, while RESTCONF equals XML or JSON. That is why option D is accurate. Option A is wrong because NETCONF does not use JSON in the same way RESTCONF does. Option B is incomplete because RESTCONF is not limited to JSON. Option C reverses the protocol encodings. This distinction matters in automation design because tool selection, content type, parsing, and API workflows differ by protocol. Reference topics: NETCONF, RESTCONF, YANG, XML encoding, JSON encoding, model-driven programmability.

A scalable two-level IS-IS design uses Level 1 areas for internal campus routing and Level 2 for the interarea backbone. Each campus should have a unique IS-IS NET area value so the internal routers belong to that campus’s Level 1 area. Internal campus routers should be configured as Level 1 routers, which keeps detailed campus prefixes inside the local area and prevents unnecessary propagation of more-specific routes to other campuses. At the edge of each campus, routers that connect the campus to the backbone should operate as Level 1/Level 2 routers. These routers connect the local Level 1 area to the Level 2 backbone and can summarize or control routing information between levels. IS-IS does not use BDR routers; that is an OSPF term, so option A is invalid. Assigning the same NET value everywhere collapses the hierarchy and defeats the segregation goal. MTU differences are not a hierarchy or route-segmentation tool. Therefore, the design should use unique NET values per campus with Level 1 internal routers and Level 1/Level 2 routers at the campus edge.