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Network Cable length and Speed.

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#1 kamayok3


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Posted 25 September 2009 - 03:41 AM

Hi all,

I would like to ask whether there are any software that can detect the length and speed of any type of LAN cable that plugged into the switches or routers?



#2 langdatyagi


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Posted 25 September 2009 - 04:19 AM

Not sure what do you mean by a software, I mean there is a command on the Cisco Switches to run a diagnostic on the cables type & integrity but it is a part of the IOS.

What exactly do you want to do?

#3 kamayok3


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Posted 25 September 2009 - 04:37 AM

Actually I know in Gigabyte motherboard there is a Smart LAN function that can detect the roughly length and speed of the LAN cable that already plug in. So, I dont know whether there is a software that can do this as well?



#4 ironcobra



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Posted 03 October 2009 - 04:23 PM

This from the configuration guide for a 3560g ios ver 12.2(25)se  I have used this before and found it to be fairly accurate. However, I feel that the results should be verified with something like a Fluke meter.

"Understanding TDR
In Cisco IOS Release 12.2(25)SE or later, you can use the Time Domain Reflector (TDR) feature to
diagnose and resolve cabling problems. When running TDR, a local device sends a signal through a cable
and compares the reflected signal to the initial signal.
TDR is supported only on copper Ethernet 10/100/1000 ports. It is not supported on 10/100 ports or
small form-factor pluggable (SFP) module ports.
TDR can detect these cabling problems:
• Open, broken, or cut twisted-pair wires—The wires are not connected to the wires from the remote
• Shorted twisted-pair wires—The wires are touching each other or the wires from the remote device.
For example, a shorted twisted pair can occur if one wire of the twisted pair is soldered to the other
If one of the twisted-pair wires is open, TDR can find the length at which the wire is open.
Use TDR to diagnose and resolve cabling problems in these situations:
• Replacing a switch
• Setting up a wiring closet
• Troubleshooting a connection between two devices when a link cannot be established or when it is
not operating properly
Table 38-2 Traceroute Output Display Characters
Character Description
* The probe timed out.
? Unknown packet type.
A Administratively unreachable. Usually, this output means that an access list is
blocking traffic.
H Host unreachable.
N Network unreachable.
P Protocol unreachable.
Q Source quench.
U Port unreachable.

Running TDR and Displaying the Results
To run TDR, enter the test cable-diagnostics tdr interface interface-id privileged EXEC command:
To display the results, enter the show cable-diagnostics tdr interface interface-id privileged EXEC
command. For a description of the fields in the display, see the command reference for this release."

This would be platform and IOS version dependant. Also these commands will not work on fiber only copper. Hope this helps you out.

#5 gokul_bruno



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Posted 06 October 2009 - 12:41 AM

Awesome....great info!

#6 pie8ter



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Posted 26 October 2009 - 02:56 AM

You can get a hardware cable tester that will tell the length.

#7 sanaycisco


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Posted 27 January 2013 - 09:11 AM

Hey anyone can give me the link for that ios with this TDR feature..urgently needed

#8 MrSquirrel


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Posted 23 March 2017 - 07:03 PM

A lot of new switch vendors have a basic TDR built into the chipset - it is okay but not as good as a dedicated Fluke TDR.
The TDR feature requires specific hardware in the switch, you can't just update the IOS and use the feature if the hardware isn't present.

Cisco have a list here:

The main advantage of a switch based TDR function is you can check out a fault remotely without leaving your desk. ^_^
For proper trouble shooting, noise, crosstalk etc you need a proper TDR.

Edited by MrSquirrel, 23 March 2017 - 07:03 PM.

#9 paul786


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Posted 16 May 2017 - 05:31 PM

as previous users informed. you can rUn cable diagnostics in cisco switches, it will tell the distance of cables as well it is connected.


test cable-diagnostics tdr int gig 1/0/1

after a minute, put below command to see the result

show cable-diagnostics tdr int gig 1/0/1

Note: Dont Run when active user connected on it, it will bounce the port.

#10 tahirsaleemjpr


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Posted 20 August 2017 - 08:54 PM

great info

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