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Glossary

R reference point

Used with ISDN networks to identify the connection

between an NT1 and an S/T device. The S/T device converts the four-wire
network to the two-wire ISDN standard network.

RADIUS

Remote Access Dial-in User Service: A protocol that is used to

communicate between the remote access device and an authentication
server. Sometimes an authentication server running RADIUS will be called a
RADIUS server.

RAM

random access memory: Used by all computers to store information.

Cisco routers use RAM to store packet buffers and routing tables, along with
the hardware addresses cache.

RARP

Reverse Address Resolution Protocol: The protocol within the TCP/

IP stack that maps MAC addresses to IP addresses. See also: ARP.

rate queue

A value, assigned to one or more virtual circuits, that specifies

the speed at which an individual virtual circuit will transmit data to the
remote end. Every rate queue identifies a segment of the total bandwidth
available on an ATM link. The sum of all rate queues should not exceed the
total available bandwidth.

RCP

Remote Copy Protocol: A protocol for copying files to or from a file

system that resides on a remote server on a network, using TCP to guarantee
reliable data delivery.

redistribution

Command used in Cisco routers to inject the paths found

from one type of routing protocol into another type of routing protocol. For
example, networks found by RIP can be inserted into an IGRP network.

redundancy

In internetworking, the duplication of connections, devices,

or services that can be used as a backup in the event that the primary con-
nections, devices, or services fail.

reference point

Used to define an area in an ISDN network. Providers

used these reference points to find problems in the ISDN network.

relay system

Another term for a router.

reliability

The measure of the quality of a connection. It is one of the met-

rics that can be used to make routing decisions.

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