Wireless Presentation Gateway
Appendix A: Planning Your Wireless
Network
Network Topology
A wireless LAN is exactly like a regular LAN, except that each network device in
the LAN uses wireless technology to connect to the network. Computers in a wire-
less LAN must be configured to share the same radio channel.
Wireless components provides LAN access for wireless network devices. An inte-
grated wireless and wired LAN is called an Infrastructure configuration. A group
of wireless users and an access point compose a Basic Service Set (BSS). Each
PC equipped with a wireless adapter in a BSS can talk to any computer in a wired
LAN infrastructure.
An infrastructure configuration extends the accessibility of a wireless user to a
wired LAN, and doubles the effective wireless transmission range for wireless
PCs. Since the access point is able to forward data within its BSS, the effective
transmission range in an infrastructure LAN is doubled.
The use of a unique ID in a Basic Service Set is essential.
The Wireless LAN Infrastructure configuration is appropriate for enterprise-scale
wireless access to a central database, or as a wireless application for mobile users.
Roaming
Infrastructure mode also supports roaming capabilities for mobile users. More
than one BSS can be configured as an Extended Service Set (ESS). This continu-
ous network allows users to roam freely within an ESS. All wireless PCs within
one Extended Service Set must be configured with the same SSID.
Selecting a feasible radio channel and optimum access point position is recom-
mended. Proper access point positioning combined with a clear radio signal will
greatly enhance performance.
15
Instant Wireless
TM
Series
14
What is DSSS? What is FHSS? And what are their differences?
Frequency Hopping Spread Spectrum (FHSS) uses a narrowband carrier that
changes frequency in a pattern that is known to both transmitter and receiver.
Properly synchronized, the net effect is to maintain a single logical channel. To
an unintended receiver, FHSS appears to be short-duration impulse noise.
Direct Sequence Spread Spectrum (DSSS) generates a redundant bit pattern for
each bit to be transmitted. This bit pattern is called a chip (or chipping code).
The longer the chip, the greater the probability that the original data can be
recovered. Even if one or more bits in the chip are damaged during transmis-
sion, statistical techniques embedded in the radio can recover the original data
without the need for retransmission. To an unintended receiver, DSSS appears
as low power wideband noise and is rejected (ignored) by most narrowband
receivers.
Would the information be intercepted while transmitting on air?
WLAN features two-fold protection in security. On the hardware side, as with
Direct Sequence Spread Spectrum technology, it has the inherent security fea-
ture of scrambling. On the software side, the WLAN series offers the encryp-
tion function (WEP) to enhance security and access control. Users can set it up
depending upon their needs.
Can Instant Wireless products support file and printer sharing?
Instant Wireless products perform the same function as LAN products.
Therefore, Instant Wireless products can work with NetWare, Windows
NT/2000, or other LAN operating systems to support printer or file sharing.
I am using 802.11b-compliant wireless equipment but still cannot connect
to my wireless network.
Verify that you are using the same IP domain as that of your wireless network.
Note: As with any Video system, image quality is only as good as
the weakest link in the video signal chain. In most cases, that
weakest link is the infrastructure cable. This especially holds true
for wireless transmission systems. To achieve the best possible
image quality with a wireless system, dedicate as much bandwidth
as possible to the video presentation.