Radius, E use of a, Server – USRobotics Instant802 APSDK User Manual

Page 317: Trans, Ion, client, Roaming

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Professional Access Point

Administrator Guide

Glossary - 317

group. A subset of

802.11e

features is described in the

WMM

specification.

R

RADIUS

The Remote Authentication Dial-In User Service (RADIUS) provides an authentication and accounting
system. It is a popular authentication mechanism for many

ISP

s.

RC4

A symmetric stream cipher provided by

RSA Security

. It is a variable key-size stream cipher with byte-

oriented operations. It allows keys up to 2048 bits in length.

Roaming

In

IEEE

802.11

parlance, roaming clients are mobile client stations or devices on a wireless network

(

WLAN

) that require use of more than one

a

as they move out of and into range of different base station

service areas. IEEE

802.11f

defines a standard by which APs can communicate information about client

associations and disassociations in support of roaming clients.

Router

A router is a network device which forwards packets between networks. It is connected to at least two
networks, commonly between two local area networks (

LAN

s) or between a

LAN

and a wide-area network

(

WAN

), for example, the Internet. Routers are located at gateways—places where two or more networks

connect.

A router uses the content of headers and its tables to determine the best path for forwarding a packet. It
uses protocols such as the Internet Control Message Protocol (ICMP), Routing Information Protocol (RIP),
and Internet Router Discovery Protocol (IRDP) to communicate with other routers to configure the best
route between any two hosts. The router performs little filtering of data it passes.

RSSI

The Received Signal Strength Indication (RSSI) an

802.1x

value that calculates voltage relative to the

received signal strength. RSSI is one of several ways of measuring and indicating radio frequency (RF)
signal strength. Signal strength can also be measured in mW (milliwatts), dBms (decibel milliwatts), and a
percentage value.

RTP

Real-Time Transport Protocol (RTP) is an Internet protocol for transmitting real-time data like audio and
video. It does not guarantee delivery but provides support mechanisms for the sending and receiving
applications to enable streaming data. RTP typically runs on top of the

UDP

protocol, but can support other

transport protocols as well.

RTS

A request to send (RTS) message is a signal sent by a client station to the access point, asking permission
to send a data packet and to prevent other wireless client stations from grabbing the radio waves. This
message is a part of the IEEE 802.11

CSMA/CA

protocol. (See also

RTS Threshold

and

CTS

.)

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