User's Manual

Table Of Contents
Wireless LAN Array
202 Glossary of Terms
Remote DC Power System (XP-3100)
An optional Xirrus proprietary product that provides distributed DC power to
multiple XS-3900 units, eliminating the need to run dedicated AC power to each
unit and facilitating backup power when connected via a UPS.
RSSI
(Received Signal Strength Indicator) A measure of the energy observed by an
antenna when receiving a signal.
SDMA
(Spatial Division Multiple Access) A wireless communications mode that
optimizes the use of the radio spectrum and minimizes cost by taking advantage
of the directional properties of antennas. The antennas are highly directional,
allowing duplicate frequencies to be used for multiple zones.
SNMP
(Simple Network Management Protocol) A standard protocol that regulates
network management over the Internet.
SNTP
(Simple Network Time Protocol) A simplified version of NTP. SNTP can be used
when the ultimate performance of the full NTP implementation described in RFC
1305 is not needed or justified.
SSH
(Secure SHell) Developed by SSH Communications Security, Secure Shell is a
program to log into another computer over a network, to execute commands in a
remote machine, and to move files from one machine to another. It provides
strong authentication and secure communications over insecure channels. SSH
protects a network from attacks, such as IP spoofing, IP source routing, and DNS
spoofing. Attackers who has managed to take over a network can only force SSH
to disconnect—they cannot “play back” the traffic or hijack the connection when
encryption is enabled. When using SSH's slogin (instead of rlogin) the entire login
session, including transmission of password, is encrypted making it almost
impossible for an outsider to collect passwords.