Installation guide

Chapter 10
100 Sniffer Technologies
 The Expert analyzer provides Expert analysis specifically for wireless
stations at the Wireless Expert layer. In addition, the Expert can
generate many wireless-specific Expert alarms. All of the usual upper
layer Expert analysis is provided. See Expert Objects and Alarms for
Wireless Networks on page 136 and Expert Alarms for Wireless
Networks on page 146.
NOTE: During monitoring or capture, the window title bar shows the channel
currently being monitored, as well as the signal strength and the type of
network being monitored (802.11a or 802.11b/g). You can use this display to
get a quick feel for the strength of the signal being monitored and determine
whether you need to move the analyzer closer to an access point to get a
stronger signal.
Differences Between Wireless Network Displays
In contrast to 802.11b networks, 802.11a and 801.11g networks support much
faster data rates. Whereas 802.11b data rates range from 1 Mbps to 11 Mbps,
802.11a and 802.11g data rates range from 6 Mbps to 54 Mbps. 802.11g is
backwards compatible with 802.11b because they both use the same
frequency spectrum. However, 802.11a uses a different frequency spectrum
than 802.11b/g. 802.11b/g works at the 2.4 to 2.4835 Ghz range and 802.11a
works at the 5.15-5.835Ghz range
.
The major differences between displays for 802.11 networks are related to the
difference in supported rates for the 802.11a/b/g standards. For example:
 Displays containing data rate information will have more rate
categories for 802.11a than they will for 802.11b/g. For example, the
Host Table for 802.11b/g networks breaks out each station’s traffic
according to whether it was sent at 1 Mbps, 2 Mbps, 5.5 Mbps, or 11
Mbps. In contrast, the Host Table for 802.11a networks will include data
rate categories for 6 Mbps, 9 Mbps, 12 Mbps, 18 Mbps, 24 Mbps, 36
Mbps, 48 Mbps, 54 Mbps, 72 Mbps, and 108 Mbps (see Notes on
Proprietary Implementations of the 802.11a Standard on page 101 for
information on why there are data rate categories beyond the 54 Mbps
upper limit of the 802.11a standard).
 There are more channels on an 802.11a network than there are on an
802.11b/g network. Because of this, channel-related displays (such as
the Channel Surfing tab in the Global Statistics application) will
display more channels for 802.11a than they will for 802.11b/g.
NOTE: Wireless network channels are based on geographical location and
the frequency band allocated in the country.