What does administrative distance represent?

• A. The trustworthiness of a route; the lower the AD, the more trustworthy
• B. The time-to-live of a route
• C. The metric value used by OSPF
• D. The number of hops to the destination

Answer: (A)

Administrative distance is a measure of how trustworthy a route’s source is. When a router learns the same destination from multiple routing protocols, it uses this distance to decide which route to install in the routing table. The lower the value, the more the router trusts that source, so the route from that protocol is preferred even if another protocol might offer a better internal metric. If two routes come from the same protocol, the protocol’s own metric decides the best path. For context, AD values are assigned by protocol type (directly connected is 0, static 1, OSPF 110, RIP 120, etc.). Time-to-live is a packet field, not a measure of route trust; OSPF uses a cost metric, not administrative distance; and hops are a routing metric in some protocols, not the AD itself.