R1 learns the same network from multiple routing protocols. Which route will be installed in the routing table?

When a router learns about the same destination network from multiple routing protocols, it uses administrative distance (AD) to determine which route to install in the IP routing table. Administrative distance is a measure of the trustworthiness of a routing information source. A lower AD value indicates a more preferred route. For example, EIGRP has a default AD of 90, OSPF has 110, and RIP has 120. The route with the lowest AD will always be chosen. The "next hop with the highest IP" is not a criterion for route selection. "Lowest cost" is used within a single routing protocol (e.g., OSPF metric, EIGRP composite metric) to choose the best path, but AD takes precedence when comparing routes from different protocols. "Shortest prefix length" is used when comparing routes to the same destination network but with different subnet masks (e.g., a /24 vs. a /28); the more specific route (longer prefix) is preferred, but AD still applies first if the routes come from different protocols.