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TDR is not applicable to this port

New Contributor II

Hi -

I'm trying to use the cable diagnostics but running into the error:

TDR is not applicable to this port!


The commands I've tried are "phy cable-diagnostics tdr 1/1/24" (for eth int 1/1/24)

and "show cable-diagnostics tdr 1/1/24" but no luck.


Does TDR have to be enabled on the switch / port before you can use it?




Contributor III
It doesn't work for me either on ICX-6430 or ICX-6610 units running 08.0.30sa, or ICX-7150 or ICX-7450 units running 08.0.80ca.

I was able to get it to fail five different ways using both commands you listed in the above hardware/software versions of ICX.  😉
  1. No TDR data on port 1/1/24
  2. TDR is not applicable to this port  (without the exclamation point)
  3. TDR is not applicable to this port! (with the exclamation point)
  4. This feature is only supported when the interface is configured for Auto-Negotiation
What I was able to get to work was optical monitoring using these commands:

Other than that, you can look at the Interfaces for anything that is out of the Normal.

For example, I do not know what switch you have, but presumably it is predominantly copper TX.

You could do a search like this (and look only at interfaces that have something connected but did not negotiate a full Gigabit connection):

switch#sh int br | exclude (None|1G)

New Contributor II
Thanks.  I appreciate the info.  These are ICX 7250s.  Glad to know I'm not doing it wrong - it just doesn't work...  🙂

Contributor III
Hi  Tommy,
It is supported on ICX 6610, ICX 6430, ICX 6430-C, ICX 6450, and ICX6450-C.
I am still looking if any other devices are included.

Virtual Cable Testing configuration notes
VCT is supported on copper ports only. It is not supported on fiber ports.
VCT is only supported when Ethernet port speed is configured to Auto. VCT does not work on ports with fixed speeds.

VCT is not supported on the following Products:
ICX 6610-24F 

-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, clearing the registers before each test, for accurate results.
Viewing the results of the cable analysis

To display the results of the cable analysis, enter a command such as the one shown in the following examples at the Privileged EXEC level of the CLI.

In the first example, the command displays TDR test results for port 1, slot 1 on device 1 in the stack. The results indicate that the port is down or the cable is not connected.

device>show cable-diagnostics tdr 1/1/1
Port      Speed Local pair Pair Length Remote pair Pair status
--------- ----- ---------- ----------- ----------- -----------
--        ----- -------     -----        ------      ----------
01        UNKWN              Pair A      <=3 M                          Open
                             Pair B      <=3 M                          Open
                             Pair C      <=3 M                          Open
                             Pair D      <=3 M                          Open

In the second test example, the TDR test results for the same port show details for an active port.

device>show cable-diagnostics tdr 1/1/1
Port      Speed Local pair Pair Length Remote pair Pair status
--------- ----- ---------- ----------- ----------- -----------
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-diagnostics tdr stackid/slot/port

In the output shown, "Local pair" indicates the assignment of wire pairs from left to right, where Pair A is the left-most pair. The following table shows the "Local pair" mapping to the T568A pin/pair and color assignment from the TIA/EIA-568-B standard.

There is a known defect FI-190238 to be fixed in 8030T code ETA is around January 31st 2019.

Hope this helps.


New Contributor II
Thanks Hashim. 

This is from an ICX7250-24P switch.  It appears that the command should work as this is a copper port, the interface is up, and is operating at 100Mbps and full duplex.  Not sure if I'm doing something wrong or it's perhaps the firmware version (currently 08030h) or something similar:

Device#show int eth 1/1/24
GigabitEthernet1/1/24 is up, line protocol is up
  Port up for 6 day(s) 51 minute(s) 40 second(s)
  Hardware is GigabitEthernet, address is 78a6.e124.d0eb (bia 78a6.e124.d0eb)
  Configured speed auto, actual 100Mbit, configured duplex fdx, actual fdx

Device#phy cable-diagnostics tdr 1/1/24
TDR is not applicable to this port!

Device#show cable-diagnostics tdr 1/1/24
TDR is not applicable to this port!

Device#clear cable-diagnostics tdr 1/1/24
TDR is not applicable to this port!

Thanks again,