Compaq WL110 User Manual page 41

When running a link test, your Client Manager station will exchange messages
with its test partner. The test partner will confirm proper receipt by returning an
acknowledgment response.
Both your wireless station and the link test partner will use these messages to:
Measure the signal to noise ratio (SNR).
Compare the total number of messages sent to the number of messages
received.
— When the communications quality is rated as "Excellent" or "Good", the
total number of lost messages should be zero.
— When communications quality is "Marginal", the total number of lost
messages may be in the range of 1% to 3%
— When the total number of messages is >5% your network environment
will most likely suffer from performance problems.
In most situations you will see that the number of lost messages will increase
whenever the level of SNR decreases.
The different fields for messages received at the different transmit rates (e.g. "11
Mbit/s", "5.5 Mbit/s", "2 Mbit/s" and "1 Mbit/s") may serve as an indicator for
network throughput efficiency.
It is normal behavior for 11Mbps Wireless LAN stations to retransmit messages
that were lost (either as a result of a frame-collision, or because the test partner
was "out-of-range"):
If a message transmission fails, your station will retransmit the "lost" frame.
If a retransmission fails repeatedly, the station will switch to a lower data
1
speed
The higher the number of messages received with the highest transmit rate, the
better your throughput efficiency. A relatively high number of messages
received at lower transmit rates may indicate:
Inadequate radio performance, which can typically be related to the level of
SNR, or
Network congestion. This may typically be the case when the SNR was
rated "Good".
In situations where you see a lot of (re)transmissions at lower data rates, the
lower data speed might be the result of:
A link test partner that is almost "out-of-range" of your Clien tManager
station. This is easily recognized by a low level of SNR.
One of the test partners is using a wireless card that does not support the
high rates.
To investigate link quality results in more detail, you can use one of the
following buttons:
1. The range of wireless data is related to the data speed. Radio messages transmitted at lower data speeds will travel
longer distances than messages at maximum data speed. In most network environments, the "Auto Fall-back" transmit
rate will yield the best performance results.
and try to transmit the message again.
Monitoring your 11Mbps Wireless LAN Network 5-7