Chapter 4 Troubleshooting
This section provides solutions to problems usually encountered during the installation and operation
of the USB adapter. Read the description below to diffuse your doubts.
What is the IEEE 802.11g standard?
802.11g is the latest IEEE standard for high-speed WLAN communications that provides up to
54Mbps data rate in the 2.4GHZ band. It has become the mainstream technology of current
WLAN networks. It uses OFDM modulation to reach higher data transmission rate and
backward compatible with 802.11b
What is the IEEE 802.11b standard?
The IEEE 802.11b WLAN standard subcommittee, which formulates a standard for the industry.
The objective is to enable WLAN hardware from different manufacturers to interoperate.
What features does the IEEE 802.11 standard provide?
The product supports the following IEEE 802.11 functions:
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CSMA/CA plus Acknowledge protocol
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Multi-Channel Roaming
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Automatic Rate Selection
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RTS/CTS feature
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Fragmentation
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Power Management
What is Ad-hoc?
An Ad-hoc mode is a wireless network type in which a group of computers equipped with
wireless adapters are connected as an independent wireless LAN without any access point. All
computers operating in this mode must be configured to share the same radio channel and
SSID.
What is Infrastructure?
The difference between Infrastructure network and Ad-hoc network is that the former requires
an Access point. The Infrastructure mode is appropriate for enterprise-scale wireless access to
a central database or provides various wireless applications for mobile users.
What is BSS ID?
An Infrastructure network is called a Basic Service Set (BSS). All the wireless stations in a BSS
must share the same BSS ID.
What is TKIP?
It is another encryption method to overcome the inherent weaknesses of WEP, a next
generation of WEP. It adopts new algorithm (Michael) to generate 128/192-bit encryption keys
and provides per-packet key mixing, a message integrity check and a re-keying mechanism.
What is AES?
AES (Advanced Encryption Standard) is a chip-based encryption method of new generation
and has been incorporated into the newly-approved security standard 802.11i. It supports 128,
192 and 256-bit encryption key length and adopts Rijndael algorithm. It is widely believed it is
impossible to crack AES.
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 transmitters and receivers. 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 is, the greater the probability that the original data can be recovered.
Even if one or more bits in the chip are damaged during transmission, 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.
What is Spread Spectrum?
Spread Spectrum technology is a wideband radio frequency technique developed by the
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