Displays the results of Virtual Cable Test
(VCT) Time Domain Reflectometry (TDR) cable diagnostic testing.
Syntax
show cable-diagnostics
tdr
stackid/slot/port
Parameters
- stackid/slot/port
- Specifies the port for which the VCT TDR cable
diagnostic testing are shown.
Usage Guidelines
VCT technology enables the diagnosis of a wire or
cable conductor by sending a pulsed signal into the conductor and examining the
reflection of that pulse. This method of cable analysis is referred to as TDR.
By
examining the reflection, the ICX device can detect and report cable data, such
as
line speed, cable length, and link pair status.
If the VCT TDR test results show that
the Pair Status is not terminated, further investigation and likely cable
replacement is required. Alternatively, connectivity issues at the end of a RJ-45
cable connector may have occurred.
For more information on analyzing TDR test results, refer to the Viewing the
Results of the Cable Analysis section of the RUCKUS FastIron Monitoring Configuration
Guide.
The show cable-diagnostics
tdr command output displays the following information:
| Output field |
Description |
| Port |
The port that was tested. |
| Speed |
The current line speed between the port in question and the connected
device. If the test successfully completes, it reflects the maximum
data transfer rate that the link can support, as resolved with
auto-negotiation, measured in megabits per second (Mbps) or gigabits
per second (Gbps). If at least one of the Pair Statuses is not
displayed as terminated, the link speed for the entire port appears
as UNKWN (unknown). |
| Local pair |
The local link name. Refer to the Viewing the Results of the Cable
Analysis section of the RUCKUS FastIron Monitoring Configuration Guide for more
information. |
| Remote pair |
The remote link name. If the pair status is open, no remote link name
appears. |
| Pair status |
The status of the link, which can be one of the following: - crosspairshort: A short circuit is
detected between different pairs. This can lead to signal
reflections and performance issues.
- crosstalk:
There is interference or noise between the ports. Refer to
the
Crosstalk Between Ports section of the RUCKUS
FastIron Monitoring Configuration Guide for more
information.
- failed: The TDR test failed, indicating
a severe issue with the cable pair. This status can indicate
a complete break in the pair or a short circuit.
- impedMis: The impedance is mismatched,
indicating that different types of cables are joined
together. This can lead to signal reflections and
performance issues.
- invalid: Indicates that there is
crosstalk between the ports. Refer to the
Crosstalk Between Ports section of the RUCKUS
FastIron Monitoring Configuration Guide for more
information.
- open: An
opening is detected in the cable resulting in a loss of
continuity. If a cable pair is open, there is no end-to-end
connectivity between the local and remote links. This status
can indicate that the cable is not connected to the port at
the far end, or the cable is connected but is damaged or
cut.
- samepairshort: A short circuit is
detected in the same cable pair. This can lead to signal
reflections and performance issues.
- terminated: The link is up, indicating
that both ends of the pair are connected to devices.
- unknown: The
TDR test was unable to determine the condition of the pair,
and further investigation is required.
|
Examples
The following example displays TDR test
results for port 1, slot 2 on device 3 in the stack. The results indicate that
the port is down or the cable is not connected. The speed of the link could not
be determined. Because there is no active connection, the local and remote pairs
are not listed. All pairs have an open status, indicating that the port is not
connected to another device or the cable might be faulty.
device> show cable-diagnostics tdr 3/2/1
Port Speed Local pair Remote pair Pair status
--------- ----- ---------- ----------- -----------
3/2/1 UNKWN Pair A Open
Pair B Open
Pair C Open
Pair D Open
The following example displays the TDR test results for an active port. The TDR
test results show that the port is active, and there is a proper connection.
The
device has successfully negotiated the link speed at 1000 mbps. The local pairs
are connected to specific remote pairs. The "Terminated" status on all pairs
signifies that there is a proper electrical connection and the link is active
and functioning correctly.
device> show cable-diagnostics tdr 3/2/1
Port Speed Local pair Remote pair Pair status
--------- ----- ---------- ----------- -----------
3/2/1 1000M Pair A Pair B Terminated
Pair B Pair A Terminated
Pair C Pair D Terminated
Pair D Pair C Terminated
History
| Release version
|
Command history
|
| 08.0.20
|
This command was introduced.
|
| 08.0.95e |
The output of this command was modified to remove the "pair length"
field. |