A

ABR. area border router.

A router that connects to areas in an OSPF network.

access layer.

The area or layer of the network that is responsible for controlling the traffic admitted to the network and for providing end user attachments to the network.

active.

An EIGRP route state that indicates the router is actively searching for alternative paths to the destination in question by querying its neighbors.

address resolution protocol.

See [ARP. Address Resolution Protocol. A method for binding network (Internet protocol) addresses to a physical layer address; it is described in IETF RFCs.]

administrative distance.

A system of weights or distances assigned to routing protocols by Cisco routers; it is used for determining which path to take to a destination network when several routing protocols have routes to it.

area border router.

See [ABR. area border router. A router that connects to areas in an OSPF network.]

ARP. Address Resolution Protocol.

A method for binding network (Internet protocol) addresses to a physical layer address; it is described in IETF RFCs.

AS. autonomous system.

A group of routers under the same administrative control.

AS path.

The set of autonomous systems a route has passed through in BGP; it is used to determine if a given path is a routing loop.

ASBR. autonomous system border router.

An OSPF router that connects two routing domains and redistributes routes from another routing protocol into OSPF.

autonomous system.

See [AS. autonomous system. A group of routers under the same administrative control.]

autonomous system border router.

See [ASBR. autonomous system border router. An OSPF router that connects two routing domains and redistributes routes from another routing protocol into OSPF.]

autosummarization.

Automatically summarizes routes to their major net mask (natural mask) when a boundary between two major networks is passed.