Checking The 10-Gigabit Ethernet Link Status - Cisco WS-C6506 Software Manual

Checking the 10-Gigabit Ethernet Link Status

Checking the 10-Gigabit Ethernet Link Status
Cable diagnostics allow you to activate the pseudorandom binary sequence (PRBS) test on the
10-Gigabit Ethernet links.
The PRBS test is currently available on the 1-port 10GBASE-E serial 10-Gigabit Ethernet module
Note
(WS-X6502-10GE).
To run the PRBS test between two devices, you must start it on both ends of the cable. If the cable is looped
back, a single end can generate the test sequence (on the Tx), verify the test sequence, and count the errors
(at the Rx).
Before the PRBS test starts, the port is automatically put in the errdisable state. The errdisable timeout
is disabled for the port so that the port is not automatically reenabled after the timeout interval ends. The
errdisable timeout is automatically reenabled on the port after the PRBS test finishes.
When the PRBS test is running, the system does not allow you to enter the set port enable and set port
disable commands.
The PRBS error counter measures the reliability of the cable. The error counter range is from 0–255. A
value of 0 signifies a perfect link connection; a value of 255 signifies that the port is faulty, not
connected, or that there is no communication through the link. If the counter does not remain at 0 for a
predetermined length of time, the link is faulty. For example, for a baud error rate (BER) of 10^-12, the
counter should remain at 0 for 100 seconds.
Each time that you access the PRBS counter by entering the show port prbs command, the PRBS error
counter value is reset to 0, and the counter begins to accumulate errors again.
The PRBS counter is a "read and clear" register. The first reading in a sequence is usually unreliable and
Note
serves primarily to purge the counter; successive readings are accurate.
To start or stop the PRBS test, perform this task in privileged mode:
Task
Step 1 Start or stop the PRBS test.
Step 2 Display the PRBS test counter
information.
This example shows how to start the PRBS test on port 1 on module 5:
Console> (enable) test cable-diagnostics prbs start 5/1
PRBS cable-diagnostic test started on port 5/1.
Console> (enable)
This example shows how to stop the PRBS test on port 1 on module 5:
Console> (enable) test cable-diagnostics prbs stop 5/1
PRBS cable-diagnostic test stopped on port 5/1.
Console> (enable)
This example shows the message that displays when the PRBS test is not supported on a module:
Console> (enable) test cable-diagnostics prbs start 6/1
Feature not supported on module 6.
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
20-10
Chapter 20
Command
test cable-diagnostics prbs {start | stop} mod/port
show port prbs
Checking Status and Connectivity
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