Noise Level; Data Throughput Efficiency; Ap Density And Roaming - Cabletron Systems RoamAbout Access Point Manual

Data Throughput Efficiency

Noise Level

The noise level indicates the presence of interference. Noise can be generated by various
devices such as microwave ovens (2.4 GHz), elevator motors, and theft detection devices
(like those used in retail stores). Noise level should always be related to the signal level:
•
A low noise level with a high signal level provides excellent communications quality.
•
A medium or high noise level with a high signal level results in an average or poor
SNR. Communications may not be as good as expected despite the strong signal level.
•
A high noise level most likely provides poor communications when the signal level is
medium or low.
Data Throughput Efficiency
Data throughput efficiency is measured in transmissions sent, lost, or received. When a data
transmission fails, the wireless device automatically retransmits the data. It is normal in
many environments for a transmission to fail occasionally. Data is not lost since the
wireless device automatically retransmits the data frames.
Many failed transmissions may result in longer network response times. Numerous
retransmissions require more time and bandwidth to maintain network communication
while contributing to the congestion of the medium. You can determine the amount of
retransmissions in a wireless network using the RoamAbout Client Utility. The client utility
is provided in the RoamAbout PC Card kit and is installed on clients.

AP Density and Roaming

AP Density is used to optimize the load balance of the number of wireless clients per
Access Point. AP Density affects the sensitivity of the radio receiver, which determines
when clients roam from one Access Point to another. Roaming allows wireless clients to
move between cells in a wireless infrastructure network without losing the connection to
the network.
The RoamAbout client can sense all the Access Points in a wireless network that are within
range. As you move the client away from its Access Point and the SNR decreases, the client
automatically switches to an Access Point with a better SNR. The client also changes its
frequency channel to match the Access Point. The transition is transparent where the user
is not aware that a transition occurred. Changing the AP Density to account for the distance
between Access Points allows the clients to roam between Access Points more efficiently.
AP Density is not used in LAN-to-LAN configurations or the ad-hoc network.
2-6 Understanding Wireless Network Characteristics