ABR (area border router)

An OSPF routing device that is situated at the border of the backbone area and one or more other OSPF areas.

access list

A set or grouping of conditions that are maintained by routers to determine which traffic qualifies for filtering, rules, and other network services.

access rate

The designated bandwidth of a particular network circuit, such as 1.544Mbps for a T1 link.


A notification packet (ACK) sent from one node to another node to verify that a message has been received or a certain event has transpired.

AD (administrative distance)

A numerical value between 0 and 255, with a higher value being preferred, that specifies the degree of trustworthiness or integrity for the source of routing information. ...

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