Glossary
435
AARP
AppleTalk Address Resolution Protocol: The protocol in an Apple-
Talk stack that maps data-link addresses to network addresses.
AARP probe packets
Packets sent by the AARP to determine whether a
given node ID is being used by another node in a nonextended AppleTalk
network. If the node ID is not in use, the sending node appropriates that
node's ID. If the node ID is in use, the sending node will select a different ID
and then send out more AARP probe packets. See also: AARP.
ABM
Asynchronous Balanced Mode: When two stations can initiate a
transmission, ABM is an HDLC (or one of its derived protocols) communi-
cation technology that supports peer-oriented, point-to-point communica-
tions between both stations.
ABR
area border router: An OSPF router that is located on the border of
one or more OSPF areas. ABRs are used to connect OSPF areas to the OSPF
backbone area.
access control
Used by Cisco routers to control packets as they pass
through a router. Access lists are created and then applied to router inter-
faces to accomplish this.
Access layer
One of the layers in Cisco's three-layer hierarchical model.
The Access layer provides users with access to the internetwork.
access link
Is a link used with switches and is only part of one Virtual
LAN (VLAN). Trunk links carry information from multiple VLANs.
access list
A set of test conditions kept by routers that determines "inter-
esting traffic" to and from the router for various services on the network.
access method
The manner in which network devices approach gaining
access to the network itself.
access rate
Defines the bandwidth rate of the circuit. For example, the
access rate of a T1 circuit is 1.544Mbps. In Frame Relay and other technol-
ogies, there may be a fractional T1 connection--256Kbps, for example--
however, the access rate and clock rate is still 1.544Mbps.
access server
Also known as a "network access server," it is a communi-
cations process connecting asynchronous devices to a LAN or WAN through
network and terminal emulation software, providing synchronous or asyn-
chronous routing of supported protocols.
Copyright ©2001 SYBEX , Inc., Alameda, CA
www.sybex.com