Wilan LIBRA 5800 AP, User Manual

Page: 119 / 156

June 2003 Rev 0 119
Appendix D: Linktest and Link Statistics
Overview
You can test the ability of a link to send and receive data with Linktest. Linktest can be run from an AP or
CPE/LCPE in P-MP or from either base or remote in P-P systems.
You can also view performance statistics with the MAC Layer Statistics menu. Some of these statistics are
• Bit Error Rate (BER)
• Received Signal Strength Indicator (RSSI)
• Fade Margin
• BER after Forward Error Correction (FEC BER)
Note:
BER and FEC BER are updated every one thousand million bits. For longer term BER, see LBER and
LFEC BER in MAC Layer Statistics , page 84 .
About Linktest
Linktest is a diagnostic tool for testing and troubleshooting a wireless link. For more information asee
Link Test , page 38
You can run Linktest from an AP to a Libra CPE, and from a Libra CPE to an AP, but not from one
Libra CPE to another. (Only while running Linktest an AP can function as a remote unit.)The unit
running Linktest is called the local. It generates pseudo-random packets of data and transmits them
to the unit at the other end of the link, which is called the remote.
The remote unit compares the pseudo-random data and accumulates bit errors, RSSI, Fade Margin,
Forward Error Correction (FEC), and packet statistics. It sends these statistics and the data back to
the local unit. The local compares the original data to what it received and displays the accumulated
statistics.
To define the link for Linktest, you need to specify the Radio Station Id of the far-end (Linktest
remote) unit and the variables
acc
,
var
and
pps
. These variables are explained below. If you do not
set these three variables, the test uses default values, also explained in the table below.
Linktest produces invalid results if run from both ends of the same link at the same time.
Performing a Linktest
Linktest is a diagnostic tool for testing wireless links. Use Linktest to check or troubleshoot a link.