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. If a port on a RUCKUS
ICX 7450 is connected to a RUCKUS
ICX 7750 device, the "impedmis"
status can occur due to a difference in voltage. Refer to
the Mismatch in Status Results section of the RUCKUS FastIron Monitoring
Configuration Guide for more information.
- 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. |