Administrative Distance
Administrative Distance (AD) is the value of reliability or trustworthiness of a protocol, for selecting routes to be placed in the routing table.
If a layer 3 device (like Router) has routes to the same destination from two different routing protocols, the route with lowest AD will be preferred and henceforth its routes will be installed in the Routing / Forwarding table.
Juniper vs Cisco –
Below comparison chart shares AD value of protocols in Cisco and Juniper platform –
PROTOCOL |
CISCO |
JUNIPER |
---|---|---|
Connected / Direct | 0 | 0 |
Static | 1 | 5 |
EIGRP Summary | 5 | – |
OSPF Internal | – | 10 |
IS-IS Level 1 Internal | – | 15 |
IS-IS Level 2 Internal | – | 18 |
BGP External | 20 | – |
EIGRP Internal | 90 | – |
OSPF All | 110 | – |
IS-IS All | 115 | – |
RIP | 120 | 100 |
OSPF External | – | 150 |
IS-IS Level 1 External | – | 160 |
IS-IS Level 2 External | – | 165 |
EIGRP External | 170 | – |
BGP All | – | 170 |
BGP Internal | 200 | – |