The administrative distance of the route is the key information that the router uses in deciding which is the best path to a particular destination. The administrative distance is a number that measures the trustworthiness of the source of the route information. The lower the administrative distance, the more trustworthy the source.
Different routing protocols have different default administrative distances. If a path has the lowest administrative distance it is installed in the routing table. A route is not installed in the routing table if the administrative distance from another source is lower.
| Route Source | Default Distance Values |
| Connected interface | 0 |
| Static route | 1 |
| Enhanced Interior Gateway Routing Protocol (EIGRP) summary route | 5 |
| External Border Gateway Protocol (BGP) | 20 |
| Internal EIGRP | 90 |
| IGRP | 100 |
| OSPF | 110 |
| Intermediate System-to-Intermediate System (IS-IS) | 115 |
| Routing Information Protocol (RIP) | 120 |
| Exterior Gateway Protocol (EGP) | 140 |
| [[On Demand Routing]] (ODR) | 160 |
| External EIGRP | 170 |
| Internal BGP | 200 |
| Unknown* | 255 |
It is possible to change the administrative distance of a static route by appending a different administrative distance to the end of the command. For example, the fol lowing command assigns the administrative distance of 130 to a static route:
ip route 10.0.0.0 255.0.0.0 serial 0/0 130
Changing the administrative distance of a static route is commonly used when configuring a backup route, called a floating static route. If you do not specify an administrative distance at the end of the static route, the default is being used.