Cisco TDR question

[AcceleratedGraphicsPort]

Good morning,

I have a little understanding how Cisco cable-diagnostics TDR works, but I had a simple question.  I have an AP that is using PoE on port 27, and when I run the test is say 55 which I assume that means 55m away?  Should that be a concern since the AP is only 24 feet away?

Interface Speed Local pair Pair length        Remote pair Pair status

--------- ----- ---------- ------------------ ----------- --------------------

Gi1/0/27  1000M Pair A     55   +/- 10 meters Pair B      Normal

                            Pair B     55   +/- 10 meters Pair A      Normal

                            Pair C     55   +/- 10 meters Pair D      Normal

                            Pair D     55   +/- 10 meters Pair C      Normal

[Leo Laohoo · Accepted solution]

Technically, it is not "55 metres away" but "at the end of 55 metres of cable".  

[AcceleratedGraphicsPort]

Hi Leo,

Thank you for the quick reply.  Should I be concerned?

[Leo Laohoo]

No, I am not. 

The TDR result are ideal (all are "Normal").

NOTE:  If this TDR is taken from an IOS-XE switch, post the complete output to the command "sh version". 

[Leo Laohoo]

IOS version 15.2(4)E10 -- I can "trust" the output from this version. 

I have stopped "trusting" TDR output from switches on IOS-XE version 16.12.X because of several unfixed bugs which can cause the TDR output provide fictitious output.