Brocade Communications Systems S3-1002483-03 Using virtual cable testing to diagnose a cable

Testing network connectivity 3

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 Brocade device displays up to three responses by default.

Refer to the BigIron RX Series Configuration Guide for information about the command syntax.

Using virtual cable testing to diagnose a cable

BigIron RX 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

•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 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:

BigIron RX# phy cable-diag tdr 1

The above command diagnoses the cable attached to port 1.

Syntax: phy cable-diag tdr <slot-num/port-num>

Viewing the results of the cable analysis

To display the results of the cable analysis, enter a command such as the following at the Privileged EXEC level of the CLI:

BigIron RX# show cable-diag tdr			1	Remote pair	Pair status
Port	Speed Local pair	Pair	Length
---------	----- ----------	-----------		-----------	-----------
01	1000M Pair A	<50M		Pair B	Terminated
	Pair B	<50M		Pair A	Terminated
	Pair C	<50M		Pair D	Terminated
	Pair D	<50M		Pair C	Terminated

Syntax: show cable-diag tdr <slot-num/port-num>

Brocade BigIron RX Series Hardware Installation Guide	77
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