Chapter 4: Troubleshooting
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Stratum Installation and Maintenance Guide
Running Diagnostics
Running Diagnostic Tests
The Stratum provides several tests to aid in the diagnosis of system components.
Ping Test
The Ping test determines if a Stratum unit can communicate with another IP address. The specified number of pings
is sent to the target address and the results are displayed in the VT-100 or web browser window. If a ping test is
performed with the remote Stratum unit, then the test exercises the full wireless link.
Loopback Test
The Stratum provides system-level loopback tests to test the IDU or ODU. The IDU test functionally isolates the
IDU from the ODU and internally connects its Tx output to its Rx input. Packets are then sent on all channels
verifying correct operation. The ODU test electrically isolates the IDU-ODU cables from the radio and connects the
two cables together inside the ODU. Note that loopback tests can only be done when you are connected through the
console port. Loopback tests must be performed when the link is in STBY (standby) mode.
BER Test
There are three Bit Error Rate tests: the IDU Loopback, the ODU Loopback, and the T1. The Diagnostic screen
reports how long a particular test has been running, the number of errors encountered, and the bit error rate in
scientific notation form (e.g., 5 x 10
-8
). The IDU and ODU Loopback tests require that the Stratum be in STBY
(standby) mode. The IDU test internally connects the IDU’s Tx output to its Rx input and runs a test pattern. The
ODU test is very similar and connects the ODU’s two cables together and runs a test pattern recording the same
information as the IDU test. For these tests, set the Test parameter to either Mark or Space. The test uses parity
checking to identify single bit errors. When set to Mark, the Parity bit is asserted in each line sent. When set to
Space, the parity bit is unasserted. These two test methods should yield similar results.
The T1 test sends a test pattern from one Stratum T1 to another radio’s T1 across the wireless link. The test runs
without impacting user data and is unidirectional so you can run the test from both ends simultaneously or from one
end at a time to determine if there is a problem and on which side. For this test, set the Test parameter to QRSS
(Quasi-Random Signal Source), which is the most commonly used test pattern for T-1 maintenance and installation.
System Errors Test
The System Errors Test utilizes the forward error correction (FEC) data to determine whether or not the aggregate
transmitted data contains uncorrectable errors. The test reflects the path direction towards the IDU that has the
system errors test enabled. Therefore, it reflects the equipment AND any path interference or distortion effects.
This test is more thorough than running the T1 BER test and it is non-intrusive with respect to customer payload
data. Also, since the test is unidirectional, it allows diagnosis of path quality (such as marginal C/I or Fade Margin)
in each direction.
The System Errors Test runs at maximum speeds (e.g., >100 Mbps for the Stratum 100) and can be set up to run
independently in both directions at the same time. Proxim recommends that you let the test run for at least 2 hours,
and if there are no errors reported by that time, the Stratum equipment is functioning properly and the radio link is
strong. The test reports how long the test has been running, the number of errors encountered, and the bit-error rate
in scientific notation form (e.g., 5 x 10
-8
). A successful System Errors Test is one with zero errors. Any errors
indicate that the system is operating on the threshold and about to go down.
Power On SelfTest
Choosing this option shows the results of the self-test diagnostics that were run when the unit was last restarted.
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