Viewing the results of the cable analysis

To display the results of the cable analysis, enter a command such as the one shown in the following examples at the Privileged EXEC level of the CLI.

In the first example, the command displays TDR test results for port 1, slot 1 on device 1 in the stack. The results indicate that the port is down or the cable is not connected.

device>show cable-diagnostics tdr 1/1/1
Port      Speed Local pair Pair Length Remote pair Pair status
--------- ----- ---------- ----------- ----------- -----------
--        ----- -------     -----        ------      ----------
01        UNKWN              Pair A      <=3 M                          Open
                             Pair B      <=3 M                          Open
                             Pair C      <=3 M                          Open
                             Pair D      <=3 M                          Open

In the second test example, the TDR test results for the same port show details for an active port.

device>show cable-diagnostics tdr 1/1/1
Port      Speed Local pair Pair Length Remote pair Pair status
--------- ----- ---------- ----------- ----------- -----------
01        1000M             Pair A     <50M        Pair B             Terminated
                            Pair B     <50M        Pair A             Terminated
                            Pair C     <50M        Pair D             Terminated
                            Pair D     <50M        Pair C             Terminated

Syntax: show cable-diagnostics tdr stackid/slot/port

In the output shown, "Local pair" indicates the assignment of wire pairs from left to right, where Pair A is the left-most pair. The following table shows the "Local pair" mapping to the T568A pin/pair and color assignment from the TIA/EIA-568-B standard.

Table 34 Local pair definition

Local pair

T568A pair and color assignment

Pair A

Pair 3 (green)

Pair B

Pair 2 (orange)

Pair C

Pair 1 (blue)

Pair D

Pair 4 (brown)

The following figure illustrates the T568A pin/pair assignment.

Figure 10  T568A pin/pair assignment

The following table describes the fields shown in the show cable-diagnostics port command output.

Table 35 Cable statistics

Field

Meaning

Port

The port that was tested.

Speed

The port current line speed.

Local pair

The local link name. Refer to the previous local pair definition table.

Pair Length

The cable length when terminated, or the distance to the point of fault when the line is not up.

Remote pair

The remote link name.

Pair status

The status of the link. This field displays one of the following:

  • Terminated: The link is up.
  • Shorted: A short is detected in the cable.
  • Open: An opening is detected in the cable.
  • ImpedMis: The impedance is mismatched.
  • Failed: The TDR test failed.