TDR Test Results - Phone restarting.

[ronicardosocruz]

Hey guys I have a question about TDR results on my Cisco 3650 Switch.

It shows up that I have a wrong cabling connection with inverted pairs and another pair with short/crosstalk.

But the phoneds and desktops connected to it works normally except the last interface below which is g1/0/8 that restarts the phone regularly. 

Can everyone confirme that I need a cabling correction or can keep this scenario. Or I really need to fix it and my phone will stop restarting.

Every response is welcome.

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

Interface Speed Local pair Pair length Remote pair Pair status
Gi1/0/12 100M

Pair A 0 +/- 1 meters Pair B Normal
Pair B 0 +/- 1 meters Pair A Normal
Pair C 32 +/- 1 meters N/A Short/Crosstalk
Pair D 32 +/- 1 meters N/A Short/Crosstalk

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

SWT0249#show cable-diagnostics tdr i g1/0/17
Gi1/0/17 100M

Pair A 0 +/- 1 meters Pair B Normal
Pair B 0 +/- 1 meters Pair A Normal
Pair C 21 +/- 1 meters N/A Short/Crosstalk
Pair D 21 +/- 1 meters N/A Short/Crosstalk

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SWT0249#show cable-diagnostics tdr i g1/0/8
Gi1/0/8 100M

Pair A 0 +/- 1 meters Pair B Normal
Pair B 0 +/- 1 meters Pair A Normal
Pair C 35 +/- 1 meters N/A Short/Crosstalk
Pair D 35 +/- 1 meters N/A Short/Crosstalk

[Martin L · Accepted solution]

I would test the phone itself, move it to different port or -better -connect to switch directly to see if it keeps on rebooting.  What is your phone model?  At speed of 100M, Pair C and D are not used at all, So this is why your other phones are OK. You will need those 2 pairs for 1Gig. 

I think that is normal results if your phone works at 100 only. I have seen this before , working fine like that. 

You will need those 2 pairs for 1Gig.

Regards, ML
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[ronicardosocruz]

Hey Martin, thanks.

I'm gonna change the port and phone because it's too old, we have several of this model 7912. Also will connect direclty.

best regards.

[Leo Laohoo]

What firmware is the switch running on?

[ronicardosocruz]

Hey Leo it's

03.07.05E

[Leo Laohoo]

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@ronicardosocruz wrote:

03.07.05E

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I have used this exact IOS-XE version in the past and I know TDR "does not work".  

The commands are accepted and they will spat out an output, however, the result cannot be accepted with confidence.