Administrative Distance
Posted on Thursday, March 4, 2010
This article was posted in Network
Adminstrative Distance ( AD)
Administrative Distance or AD is an integer from 0 to 255 that rates the trustworthiness of routing information received on a router from a neighboring router. The AD is used as the tie-breaker when a router has multiple paths from different routing protocols to the same destination. The lower the path’s AD ,the more likely it is to be used. In case a routing protocol has multiple path within the same routing protocol to the same destination, the metric is used as a tie-breaker. The route with the lowest metric is the path taken.
Below are the Adminstrative Distance of differnet Routing Protocols
| Directly Connected Interface | 0 |
| Static Route | 1 |
| EIGRP | 90 |
| IGRP | 100 |
| OSPF | 110 |
| RIP | 120 |
| External EIGRP | 170 |
| Unknown | 255 |