Which WAN topology has the highest degree of reliability?

full mesh. Cisco forwarding uses longest-prefix match first, then administrative distance and metric when multiple sources compete. Cisco CCNA 200-301 v1.1 includes this under Network Fundamentals, where the expected skill is identifying the mechanism that actually satisfies the scenario. The wording usually gives the decisive clue: a protocol number, a route prefix, a control-plane role, a wireless security method, or a management command. Wrong choices either do not match the destination prefix, point to the wrong next hop, or fail to create the required primary or backup route. In a real network, selecting the wrong option would usually produce a failed adjacency, broken client connectivity, insecure management access, or an incorrect forwarding path. The selected answer matches the Cisco behavior and configuration model required by the question, so it is retained as the verified answer for this item.