Administrative distance

If a router learns of a network from multiple sources (routing protocols or static configurations), it uses the administrative distance value to determine which route to install in the routing (forwarding) table. The default administrative distance values are listed here.

Source Administrative Distance

Connected interface - 0
Static route - 1
EIGRP summary route - 5
External BGP - 20
Internal EIGRP - 90
IGRP - 100
OSPF - 110
IS-IS - 115
RIP - 120
Exterior Gateway Protocol - 140
On-Demand Routing - 160
External EIGRP - 170
Internal BGP - 200
Unknown - 255

Administrators can create static routes that “float.” A floating static route means the administrator increases the administrative distance of the static route to be greater than the administrative distance of the dynamic routing protocol in use. This means the static route is relied on only when the dynamic route does not exist.