User Manual

factors as signal strength and quality, as well as the message load currently
being carried by each Access Point and the distance of each Access Point to the
wired backbone. Based on that information, the node next selects the right
Access Point and registers its address. Communications between end node and
host computer can then be transmitted up and down the backbone.
As the user moves on, the end nodes RF transmitter regularly checks the sys-
tem to determine whether it is in touch with the original Access Point or
whether it should seek a new one. When a node no longer receives acknowl-
edgment from its original Access Point, it undertakes a new search. Upon find-
ing a new Access Point, it then reregisters, and the communication process con-
tinues.
What is BSS ID?
A specific Ad hoc LAN is called a Basic Service Set (BSS). Computers in a
BSS must be configured with the same BSS ID.
What is ESS ID?
An Infrastructure configuration could also support roaming capability for
mobile workers. More than one BSS can be configured as an Extended Service
Set (ESS). Users within an ESS could Roam freely between BSSs while served
as a continuous connection to the network wireless stations and Access Points
within an ESS must be configured with the same ESS ID and the same radio
channel.
What is ISM band?
The FCC and their counterparts outside of the U.S. have set aside bandwidth
for unlicensed use in the ISM (Industrial, Scientific and Medical) band.
Spectrum in the vicinity of 2.4 GHz, in particular, is being made available
worldwide. This presents a truly revolutionary opportunity to place convenient
high-speed wireless capabilities in the hands of users around the globe.
What is Spread Spectrum?
Spread Spectrum technology is a wideband radio frequency technique devel-
oped by the military for use in reliable, secure, mission-critical communica-
tions systems. It is designed to trade off bandwidth efficiency for reliability,
integrity, and security. In other words, more bandwidth is consumed than in the
case of narrowband transmission, but the trade off produces a signal that is, in
effect, louder and thus easier to detect, provided that the receiver knows the
parameters of the spread-spectrum signal being broadcast. If a receiver is not
tuned to the right frequency, a spread-spectrum signal looks like background
noise. There are two main alternatives, Direct Sequence Spread Spectrum
(DSSS) and Frequency Hopping Spread Spectrum (FHSS).
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Can I play multiplayer games with other members of the wireless network?
Yes, as long as the game supports multiple players over a LAN (local area net-
work). Refer to the game's user guide for more information.
What is IEEE 802.11b standard?
The IEEE 802.11b Wireless LAN standards subcommittee, which is formulat-
ing a standard for the industry. The objective is to enable wireless LAN hard-
ware from different manufacturers to communicate.
What IEEE 802.11b features are supported?
The product supports the following IEEE 802.11b functions:
• CSMA/CA plus Acknowledge protocol
• Multi-Channel Roaming
• Automatic Rate Selection
• RTS/CTS feature
• Fragmentation
• Power Management
What is Ad-Hoc?
An Ad-Hoc wireless LAN is a group of computers, each with a WLAN adapter,
connected as an independent wireless LAN. Ad hoc wireless LAN is applica-
ble at a departmental scale for a branch or SOHO operation.
What is Infrastructure?
An integrated wireless and wired LAN is called an Infrastructure configura-
tion. Infrastructure is applicable to enterprise scale for wireless access to cen-
tral database, or wireless application for mobile workers.
What is Roaming?
Roaming is the ability of a portable computer user to communicate continu-
ously while moving freely throughout an area greater than that covered by a sin-
gle Access Point. Before using the roaming function, the workstation must
make sure that it is the same channel number with the Access Point of dedicat-
ed coverage area.
To achieve true seamless connectivity, the wireless LAN must incorporate a
number of different functions. Each node and Access Point, for example, must
always acknowledge receipt of each message. Each node must maintain contact
with the wireless network even when not actually transmitting data. Achieving
these functions simultaneously requires a dynamic RF networking technology
that links Access Points and nodes. In such a system, the user’s end node under-
takes a search for the best possible access to the system. First, it evaluates such
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Instant Wireless
TM
Series
Wireless PCI Card