Troubleshooting Network Connections; Using Virtual Cable Testing To Diagnose A Cable - Foundry Networks FES Installation Manual

Foundry Hardware Installation Guide for the FES, FESX, and FWSX
Syntax: traceroute <host-ip-addr> [maxttl <value>] [minttl <value>] [numeric] [timeout <value>]
[source-ip <ip addr>]
The CLI displays trace route information for each hop as soon as the information is received. Traceroute requests
display all responses to a given TTL. In addition, if there are multiple equal-cost routes to the destination, the
Foundry device displays up to three responses by default.
See the Foundry Switch and Router Command Line Interface Reference for information about the command
syntax.

Troubleshooting Network Connections

• For the indicated port, verify that both ends of the cabling (at the Foundry device and the connected device)
are snug.
• Verify that the Foundry device and the connected device are both powered on and operating correctly.
• Verify that you have used the correct cable type for the connection:
• For twisted-pair connections to an end node, use straight-through cabling.
• 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.
• For copper ports, you can test the cable using Virtual Cable Testing. See "Using Virtual Cable Testing to
Diagnose a Cable" on page 4-10.
• If the other procedures don't resolve the problem, try using a different port or a different cable.

Using Virtual Cable Testing to Diagnose a Cable

FESX and FWSX devices provide support for 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 Foundry device can detect and report cable statistics such as; local and remote link
pair, cable length, and link status.
Configuration Notes
• This feature is supported in the following configurations:
• FESX devices running software release 01.1.00 or later
• FWSX devices and all associated software releases
• 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/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 scenario, it is recommended that you run the TDR test a few times for accurate results.
Command Syntax
To diagnose a cable using TDR, enter commands such as the following at the Privileged EXEC level of the CLI:
FESX Switch# phy cable-diag tdr 1
The above command diagnoses the cable attached to port 1.
4 - 10 © 2006 Foundry Networks, Inc. June 2006