Cisco administrative distance
Used to pick between two routes with the same prefixes.
Think of it like protocol preference.
Prefix
- The network and masking bits for a route
Same subnet length
10.0.0.0/24 via 192.168.0.1 - OSPF
10.0.0.0/24 via 192.168.0.2 - EIGRP
EIGRP wins because \( 90 < 110 \).
Most specific prefix
Which route is selected for the destination 10.0.0.1?
10.0.0.0/25 via 192.168.0.1 - OSPF
10.0.0.0/24 via 192.168.0.2 - EIGRP
OSPF wins because /25 is a more specific path.
Table
| Protocol | Administrative Distance |
|---|---|
| Connected | 0 |
| Static | 1 |
| EIGRP Summary | 5 |
| eBGP | 20 |
| EIGRP Internal | 90 |
| OSPF | 110 |
| IS-IS | 115 |
| RIP | 120 |
| ODR | 160 |
| EIGRP External | 170 |
| iBGP | 200 |
| Unknown/Infinite | 255 |
References
Describe Administrative Distance - Cisco
Troubleshooting TechNotes - What is Administrative Distance? - Cisco