TDR cable testing support on the 2960-X

[Paul McGurn]

Hi,

I'm finding what looks like Cisco blanket disabling the TDR (cable test) feature on switchports on the 2960-X if the downstream device is negotiated to anything other than 1000Mbps.  Is this done intentionally, or am I hitting some kind of bug?

When running "test cable tdr int <int>", and then waiting several seconds, afterwards running "show cable tdr int <int>", the results are basically useless if the port isn't connected to a 1000Mbps device.  It shows the table of results with all "N/A", and at the bottom it simply says:

Cable Diage is not available at 100 Mbps and 10 Mbps.

This is on software version 15.0(2)EX4 .

This seems a little silly to me, since it worked on the non X-series 2960's in the past, IIRC.

[Charles Hill]

Try entering the "media rj" command" before you run the TDR test.

Below is the posting where I located this TDR info. 

https://supportforums.cisco.com/document/74231/how-use-time-domain-reflectometer-tdr

Thanks to Leo's posting!

[Leo Laohoo]

Here's what I "can" tell you about 2960X and TDR: 

1.  2960X TDR currently (emphasis on the word "CURRENTLY") supports only 1000BaseTx.  

2.  2960X TDR currently (emphasis on the word "CURRENTLY") CANNOT support 10/100BaseTx.  

[Charles Hill]

Good morning Leo,

Sorry for mis quoting your posting.

After re-reading your posting, I noticed it did not reference 2960X.

However the info below is from the 2960X system management commands (document)

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960x/software/15-0_2_EX/system_manage/command_reference/b_sm_152ex_2960_x_cr/b_sm_152ex_2960_x_cr_chapter_010.html#wp2269891406

 

Usage Guidelines

TDR is supported only on 10/100/100 copper Ethernet ports. It is not supported on 10-Gigabit Ethernet ports or small form-factor pluggable (SFP) module ports.

I suspect the 10/100/100 is a typo, since it is stating 100 twice.

What are your thoughts on this document(TDR is supported only on 10/100/100)?

[Leo Laohoo]

What are your thoughts on this document(TDR is supported only on 10/100/100)?

This is a Cisco "document bug" and you are so going to get me in a deep-heap-of-cow-manure!  

All I can say or all I am ALLOWED TO SAY is:  CURRENT IOS restricts the 2960X's TDR function on 1000BaseTx.   Again, emphasis on the word "CURRENT".  

What I failed to mention in my last post is this:  Talk to your Cisco SE/AM.  Reach out to them.  TDR function, over the last few years, have gained some sort of "traction" inside Cisco.  One thing I can say is the people involved have listened to what I have to say and they are actively doing something about it.  Talking to your Cisco SE/AM means feedback gives the developers and the switching/2960X BU the assurance that what they are doing (improving 2960X functionality) is not in vain.  

I cannot say anything else because I made a promise to keep my big "trap" shut in exchange for something.  

Sorry for mis quoting your posting.

Apologies NOT REQUIRED.   I deliberately didn't put anything about TDR functionalities on my blog because I only have a very limited amount of 2960X to play with.  By the time I finished testing (TDR on a 2960X), I was given the chance to do something about the "shortfall".  Without being asked, I decided to hold off on making a comment until I see something.   So far, the future looks bright.  

[Charles Hill]

Thank you Leo!  

I understand now.

[Paul McGurn]

Well, at least there seems to be some hope there.  TDR at the switchport, regardless of speed, is definitely more ideal than unplugging ports to plug in a 3rd party tool, etc.  I'm still getting one (because we love cool toys), but I do have hope they'll ship an IOS update to close this gap.

[Leo Laohoo]

Well, at least there seems to be some hope there. 

There is hope. 

but I do have hope they'll ship an IOS update to close this gap.

No comment.  

I'm still getting one 

Don't forget to get maintenance ... and we're going to be getting 1T-3000-ACK-LRAT2.

[Paul McGurn]

Thanks Leo.

I guess this is my nudge to go buy a Fluke MicroScanner and works with my hands for a change :).

[Henk Spaan]

Yeah no luck with TDR on 2960x on a 100Mb/s port

sw1cab1.keesom10h#show cable-diagnostics tdr int gi 2/0/36
TDR test last run on: August 18 15:47:10

Interface Speed Local pair Pair length Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi2/0/36 100M Pair A N/A N/A Not Completed
Pair B N/A N/A Not Completed
Pair C N/A N/A Not Completed
Pair D N/A N/A Not Completed

sw1cab1.keesom10h#

sw1cab1.keesom10h#show int gi 2/0/36 | i media
Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX