Testing the Cable

Enter the test cable-diagnostics command in any context to begin cable diagnostics for the transceiver. The diagnostic attempts to identify cable faults. The tests may take a few seconds to complete for each interface. There is the potential of link loss during the diagnostic.

Syntax:


test cable-diagnostics [port-list]

Invokes cable diagnostics and displays the results.

Output from test cable-diagnostics command

Switch # test cable-diagnostics a23-a24

 The ‘test cable-diagnostics’ command will cause a loss of link and will take a few seconds per 
 interface to complete.

 Continue (Y/N)? y


MDI  Cable     Distance  Pair  Pair      MDI 
 Port  Pair  Status     to Fault  Skew  Polarity  Mode
 ----- ----- ---------- --------- ----- --------- ------ 
 A23   1-2   OK         0 m       6 ns  Normal    MDIX
       3-6   OK         0 m       0 ns  Normal
       4-5   OK         0 m       6 ns  Normal    MDIX
       7-8   OK         0 m       6 ns  Normal
 A24   1-2   Short      2 m
       3-6   Impedance  3 m
       4-5   Impedance  3 m
       7-8   Open       1 m

Copper cable diagnostic test results

switch# show interfaces transceiver a23 detail

 Transceiver in A23
  Interface Index   : 23
  Type              : 1000T-sfp
  Model             : J8177C 
  Connector Type    : RJ45
  Wavelength        : n/a
  Transfer Distance : 100m (copper), 
  Diagnostic Support : VCT
  Serial Number     : US051HF099

  Link Status       : Up
  Speed             : 1000
  Duplex            : Full

       MDI   Cable      Distance  Pair  Pair      MDI 
 Port  Pair  Status     to Fault  Skew  Polarity  Mode
 ----- ----- ---------- --------- ----- --------- ----- 
 A23   1-2   OK         0 m       6 ns  Normal    MDIX
       3-6   OK         0 m       0 ns  Normal
       4-5   OK         0 m       6 ns  Normal    MDIX
       7-8   OK         0 m       6 ns  Normal

   Test Last Run   : Fri Apr 22 20:33:23 2011

Parameter	Description
Interface Index	The switch interface number
Transceiver-type	Pluggable transceiver type
Transceiver model	Pluggable transceiver model
Connector-type	Type of connector of the transceiver
Wavelength	For an optical transceiver: the central wavelength of the laser sent, in nm. If the transceiver supports multiple wavelengths, the values will be separated by a comma. An electrical transceiver value is displayed as N/A.
Transfer Distance	Link-length supported by the transceiver in meters. The corresponding transfer medium is shown in brackets following the transfer distance value, For example, 50um multimode fiber. If the transceiver supports multiple transfer media, the values are separated by a comma.
Diagnostic Support	Shows whether the transceiver supports diagnostics: None Supported DOM Supported VCT Supported
Serial Number	Serial number of the transceiver
Link Status	Link up or down
Speed	Speed of transceiver in Mbps
Duplex	Type of duplexing
Cable Status	Values are OK, Open, Short, or Impedance
Distance to Fault	The distance in meters to a cable fault (accuracy is +/- 2 meters); displays 0 (zero) if there is no fault
Pair Skew	Difference in propagation between the fastest and slowest wire pairs
Pair Polarity	Signals on a wire pair are polarized, with one wire carrying the positive signal and one carrying the negative signal.
MDI Mode	The MDI crossover status of the two wire pairs (1&2, 3&6, 4&5, 7&8), will be either MDI or MDIX