Define Administrative Distance and name an example of a lower versus higher AD value.

• A. Administrative Distance is the trustworthiness of a route source; static routes have AD 1 (lower) and RIP has AD 120 (higher).
• B. Administrative Distance is the time to live of a route; static routes have AD 1 and RIP 120
• C. Administrative Distance is the routing cost; static routes 1, RIP 120
• D. Administrative Distance is the number of hops to destination; static 1 and RIP 120

Answer: (A)

Administrative Distance is the trust level assigned to a routing source. Routers use this value to decide which route to use when there are multiple routes to the same destination from different sources. A lower value means the source is more trusted, so its routes are preferred over sources with higher values.

Static routes are configured by an administrator and are considered highly trustworthy, so they have a very low AD of 1. RIP, a distance-vector protocol, has a higher value of 120, making its routes less trusted than a static route. Therefore, if both a static route and a RIP-learned route to the same destination exist, the router will favor the static route because of the lower Administrative Distance.

The other concepts mentioned—time to live, routing cost, and number of hops—do not define Administrative Distance. TTL is a packet life mechanic, routing cost is an internal metric used by a routing protocol to choose paths within that protocol, and hop count is a metric used by some protocols but not the AD ranking used to select between different sources.