CCNA 3.2.e: Administrative distance

Overview:

Administrative distance is what is used to select the best path when a router has two different paths to the same destination via two different routing protocols.

Study Notes:

• Most routing protocols are not compatible with other protocols.
• In a network with multiple routing protocols, being able to select the best path between multiple protocols is critical.
• Administrative distance defines the reliability of a routing protocol.
• Each routing protocol is prioritized in order of most to least reliable (believable) with the help of an administrative distance value.
• IPv6 uses the same distances as IPv4.
• Default Administrative Distances:

See CCNA 3.3.a: Admin Distance for a full list