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ArubaOS-Switch test cable-diagnostic versus duplex/speed on diagnosed port.

Hello,

 

How cable-diagnostic behaves when the test cable-diagnostic is performed on a ethernet interface connected to a 100Mbit Full-Duplex (eventually with PoE) [*] host or a 100Mbit Half-Duplex [**] host? 

 

I admit I've to diagnose if those host types are correctly set by using the Auto-Sensing...but, apart from that, I want to know if test cable-diagnostic results can differ if the cable's end is connected to hosts behaving differently (100FDx vs 100HDx vs 1000FDx). 

 

[*] such as a DECT-IP Base Station (as per Auto-Sensing)

 

I observe this:

Aruba(config)# test cable-diagnostics ethernet 1
This command will cause a loss of link on all tested ports and will take
several seconds per port to complete.  Use the 'show cable-diagnostics'
command to view the results.

Continue (y/n)?  y
Aruba(config)# test cable-diagnostics ethernet 2
This command will cause a loss of link on all tested ports and will take
several seconds per port to complete.  Use the 'show cable-diagnostics'
command to view the results.

Continue (y/n)?  y
Aruba(config)# test cable-diagnostics ethernet 3
This command will cause a loss of link on all tested ports and will take
several seconds per port to complete.  Use the 'show cable-diagnostics'
command to view the results.

Continue (y/n)?  y

Aruba(config)# show cable-diagnostics ethernet 1

 Cable Diagnostic Status - Copper Ports

       MDI    Cable       Cable Length or
  Port Pair   Status      Distance to Fault
  ---- ------ ----------- ---------------------
  1    1-2    OK          33m
       3-6    OK          38m
       4-5    Short       31m
       7-8    Short       32m

Aruba(config)# show cable-diagnostics ethernet 2

 Cable Diagnostic Status - Copper Ports

       MDI    Cable       Cable Length or
  Port Pair   Status      Distance to Fault
  ---- ------ ----------- ---------------------
  2    1-2    OK          51m
       3-6    OK          51m
       4-5    Open        1m
       7-8    Short       53m

Aruba(config)# show cable-diagnostics ethernet 3

 Cable Diagnostic Status - Copper Ports

       MDI    Cable       Cable Length or
  Port Pair   Status      Distance to Fault
  ---- ------ ----------- ---------------------
  3    1-2    OK          31m
       3-6    OK          36m
       4-5    Short       34m
       7-8    Short       34m

Aruba(config)# show interfaces status
  Port     Name       Status  Config-mode   Speed    Type       Tagged Untagged
  -------- ---------- ------- ------------- -------- ---------- ------ --------
  1        DECT-IP... Up      Auto          100FDx   100/1000T  No     1000
  2        DECT-IP... Up      Auto          100FDx   100/1000T  No     1000
  3        DECT-IP... Up      Auto          100FDx   100/1000T  No     1000

Aruba(config)# show interfaces

 Status and Counters - Port Counters
 
                                                                 Flow Bcast
  Port         Total Bytes    Total Frames   Errors Rx Drops Tx  Ctrl Limit
  ------------ -------------- -------------- --------- --------- ---- -----
  1            26,397,080     401,898        0         0         off  0
  2            26,444,482     402,386        0         0         off  0
  3            26,359,582     401,525        0         0         off  0

As you note on all three ports (Spectralink DECT IP Base Station working at 100Mbps Full-Duplex) pair 7-8 results as "Short"...but on Port 2 pair 4-5 is "Open" while the very same pair on Port 1 and 3 results "Short"...so, in the end, is "Short" on 4-5 and 7-8 normal for 100Mbps Full-Duplex and "Open" means that our port 2 connected Spectralink DECT IP Base Station has a real problem? 

 

 

[**] such as a Label Printer (as per Auto-Sensing)

Aruba Employee

Re: ArubaOS-Switch test cable-diagnostic versus duplex/speed on diagnosed port.

This is the output from three devices that we re plugged into one of the test switches. Ports 8 and 21 report in the switch as 100 full duplex.

 

2930F-31(config)# sh cable-diagnostics

 Cable Diagnostic Status - Copper Ports

       MDI    Cable       Cable Length or
  Port Pair   Status      Distance to Fault
  ---- ------ ----------- ---------------------
  8    1-2    OK          0m
       3-6    OK          0m
       4-5    Short       1m
       7-8    Short       1m
  16   1-2    OK          0m
       3-6    OK          0m
       4-5    OK          0m
       7-8    OK          0m
  21   1-2    OK          4m
       3-6    OK          4m
       4-5    Short       0m
       7-8    Short       0m

It is interesting that they both report pairs 4-5 and 7-8 as "short".



Richard Litchfield, HPE Aruba
Consulting System Engineer
Network Ambassador
Highlighted
MVP Expert

Re: ArubaOS-Switch test cable-diagnostic versus duplex/speed on diagnosed port.

Yes, it's pretty much interesting (and strange too)...but this pattern can't be taken as a general rule...I've found an host (not a DECT IP BS, I haven't any LLDP nor CDP references about it) which is recognized by the switch as 100Mbps Full-Duplex (Auto-Sensing) and it shows four "OK" on the four pairs:

 

Aruba(config)# test cable-diagnostics ethernet 26
This command will cause a loss of link on all tested ports and will take
several seconds per port to complete.  Use the 'show cable-diagnostics'
command to view the results.

Continue (y/n)?  y

DL1-113# show cable-diagnostics ethernet 26

 Cable Diagnostic Status - Copper Ports

       MDI    Cable       Cable Length or
  Port Pair   Status      Distance to Fault
  ---- ------ ----------- ---------------------
  26   1-2    OK          43m
       3-6    OK          41m
       4-5    OK          43m
       7-8    OK          43m

	   
Aruba(config)# show interfaces

 Status and Counters - Port Counters

                                                                 Flow Bcast
  Port         Total Bytes    Total Frames   Errors Rx Drops Tx  Ctrl Limit
  ------------ -------------- -------------- --------- --------- ---- -----
  26           30,936         437            0         0         off  0

  
Aruba(config)# show interfaces status

  Port     Name       Status  Config-mode   Speed    Type       Tagged Untagged
  -------- ---------- ------- ------------- -------- ---------- ------ --------
  26       Sub_192... Up      Auto          100FDx   100/1000T  1000   4
  
Aruba(config)# show interfaces brief

 Status and Counters - Port Status

                          | Intrusion                           MDI  Flow Bcast
  Port         Type       | Alert     Enabled Status Mode       Mode Ctrl Limit
  ------------ ---------- + --------- ------- ------ ---------- ---- ---- -----
  26           100/1000T  | No        Yes     Up     100FDx     MDIX off  0

So it could be difficult to understand what is the correct output one should expect.

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