User's Manual

Troubleshooting
Tsunami QB-8100 Series (100 Mbps/5 Mbps Models) Installation and Management Guide 197
– In Errors and Out Errors should never happen; however, it might happen if a frame’s CRC was correct while the
content was still invalid.
• Monitor / Wireless / WORP (Statistics on WORP): WORP runs on top of normal Ethernet, which means that the WORP
frame is in fact the data field of the Ethernet frame. Send Failure or Send Retries must be low in comparison to Send
Success. Low is about 1%. The same applies for Receive Success versus Receive Retries and Receive Failures. Note that
the Receive Failures and Retries can be inaccurate. A frame from the remote site might have been transmitted without
even being received; therefore, the count of that frame might not have been added to the statistics and the receiver
simply could not know that there was a frame.
– Remote Partners indicates how many End Point B units are connected (in case of an End Point A) or whether an End
Point A is connected (in case of an End Point B).
8.4.19 Analyzing the Spectrum
The ultimate way to discover whether there is a source of interference is to use a spectrum analyzer. Usually, the antenna is
connected to the analyzer when measuring. By turning the antenna 360 degrees, one can check from which direction the
interference is coming. The analyzer will also display the frequencies and the level of signal is detected. Proxim recommends
performing the test at various locations to find the most ideal location for the equipment.
8.4.19.1 Avoiding Interference
When a source of interference is identified and when the level and frequencies are known, the next step is to avoid the
interference. Some of the following actions can be tried:
• Changing the channel to a frequency away from the interference is the first step in avoiding interference. The installer
can select a DFS Preferred Channel.
• Each antenna has a polarization; try to change to a polarization different from the interference.
• A small beam antenna looks only in one particular direction. Because of the higher gain of such an antenna, lowering
the output power or adding extra attenuation might be required to stay legal. This solution cannot help when the
source of interference is right behind the remote site.
• Lowering the antennas can help avoid seeing interference from far away.
Move the antennas to a different location on the premises. This causes the devices to look from a different angle, causing a
different pattern in the reception of the signals. Use obstructions such as buildings, when possible, to shield from the
interference.
8.4.19.2 Conclusion
A spectrum analyzer can be a great help to identify whether interference might be causing link problems on Tsunami
QB-8100 devices.
Before checking for interference, the link should be verified by testing in an isolated environment, to make sure that the
hardware works and your configurations are correct. The path analysis, cabling and antennas should be checked as well.
Statistics in the web interface under Monitor indicates if there is a link, if the link is healthy, and a continuous test can be
done using the Link Test.
– Base Announces should increase continuously.
– Registration Requests and Authentication Requests should be divisible by 3. WORP is designed in a way that each
registration sequence starts with 3 identical requests. It is not a problem if, once in a while, one of those requests is
missing. Missing requests frequently is to be avoided.
• Monitor / Per Station (Information per connected remote partner): Check that the received signal level (RSL) is the
same on both sides. This should be the case if output power is the same. Two different RSLs indicate a broken
transmitter or receiver. A significant difference between Local Noise and Remote Noise could indicate a source of
interference near the site with the highest noise. Normally, noise is about –80 dBm at 36 Mbps. This number can vary
from situation to situation, of course, also in a healthy environment.