Explaing for TDR results

[abhiamoli]

I have the below output can anyone help me in explaining the same.

Interface Speed Local pair Pair length Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi0/9 1000M Pair A 147 +/- 4 meters Pair A Normal
                     Pair B 150 +/- 4 meters Pair B Normal
                     Pair C 145 +/- 4 meters Pair C Normal
                     Pair D 145 +/- 4 meters Pair D Normal

[balaji.bandi]

As per the output all good - Normal means good, we need to worry if only Open.

here is good explanation :

https://community.cisco.com/t5/networking-documents/how-to-use-time-domain-reflectometer-tdr/ta-p/3119327

[abhiamoli]

Can pair length create some issue?

[balaji.bandi]

we are not sure what cable used, so i suggest to look this document length support by cat cable based on category :

https://www.digitaltrends.com/computing/different-types-of-ethernet-cables-explained/

by the way what is the model of the switch and end device ? what IOS running ?

[abhiamoli]

The cable used is CAT6.

And below are the other details - 

Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 24 WS-C2960G-24TC-L 12.2(25)SEE2 C2960-LANBASE-M

[Leo Laohoo]

I would be using a more recent IOS.  
I suspect the output to the cable length is a bug.

[Martin L]

Can pair length create some issue?

No, as long as length is within margin of error , +/- 4 meters, your results look OK.  The Length is not precise measurement when done with switch tdr. If you had bigger value discrepancies in length, then you worry about it. 

[Leo Laohoo]

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@abhiamoli wrote:

Interface Speed Local pair Pair length        Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi0/9     1000M Pair A     147 +/- 4 meters   Pair A      Normal
                Pair B     150 +/- 4 meters   Pair B      Normal
                Pair C     145 +/- 4 meters   Pair C      Normal
                Pair D     145 +/- 4 meters   Pair D      Normal

---

What firmware is the switch running on?  I am thinking this could be a 2960G or a 3560G?