Troubleshooting Network Connections; Using Virtual Cable Testing To Diagnose A Cable - Brocade Communications Systems FWS648G-POE Hardware Installation Manual

Troubleshooting network connections

Follow these guidelines when troubleshooting your network connections:
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Using Virtual Cable Testing to diagnose a cable

FastIron WS devices support Virtual Cable Test (VCT) technology. VCT technology enables you to
diagnose a conductor (wire or cable) by sending a pulsed signal into the conductor, then examining
the reflection of that pulse. This method of cable analysis is referred to as Time Domain
Reflectometry (TDR). By examining the reflection, the Brocade device can detect and report cable
statistics such as local and remote link pair, cable length, and link status.
Configuration notes
Refer to these configuration notes when troubleshooting network connections:
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Command syntax
To diagnose a cable using TDR, enter a command such as the following at the Privileged EXEC level
of the CLI.
FWSSwitch#phy cable-diag tdr 0/1/1
The above command diagnoses the cable attached to port 0/1/1.
Syntax: phy cable-diag tdr <port-num>
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For the indicated port, verify that both ends of the cabling (at the Brocade device and the
connected device) are snug.
Verify that the Brocade device and the connected device are both powered on and operating
correctly.
Verify that you have used the correct cable type for the connection:
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For twisted-pair connections to an end node, use straight-through cabling.
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For fiber-optic connections, verify that the transmit port on the device is connected to the
receive port on the connected device, and that the receive port on the device is connected
to the transmit port on the connected device.
Verify that the port has not been disabled through a configuration change. You can use the CLI.
If you have configured an IP address on the device, you also can use the Web management
interface or IronView Network Manager.
If the other procedures do not resolve the problem, try using a different port or a different
cable.
This feature is supported on copper ports only. It is not supported on fiber ports.
The port to which the cable is connected must be enabled when you issue the command to
diagnose the cable. If the port is disabled, the command is rejected.
If the port is operating at 100 Mbps half-duplex, the TDR test on one pair will fail.
If the remote pair is set to forced 100 Mbps, any change in MDI or MDIX may cause the device
to interpret the Multilevel Threshold-3 (MLT-3) as a reflected pulse, in which case, the device
will report a faulty condition. In this case, Brocade recommends that you run the TDR test a few
times for accurate results.
Troubleshooting network connections
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