Alcatel-Lucent 9500 MXC User Manual page 650

Chapter 1. Commissioning
Silent Tx Switching Procedure
Vol. V-1-12
remains with the secondary RAC, which is now online for Tx and Rx.
5. Wait for 60 seconds, confirm that NCC and RAC status LEDs are green, then
withdraw the online secondary RAC and confirm that service is restored
within a count of one errored second (possibly two). At this point the primary
RAC is online for Tx and Rx.
6. On completion of the tests ensure the remote loopback is disabled, or will
time-out.
7. Use the System/Controls screen to return to default online status (primary
RAC Tx and secondary RAC Rx), and if an unequal coupler is used with a
hot-standby installation, check that the online Tx is selected for the low-loss
side.
The procedure uses the Tx mute function to simulate a path failure.
Test procedure:
1. Set a BER test on a DAC trib with a loopback at the remote Node. Confirm
error-free operation.
2. Go to the System/Controls screen and select the protected link.
3. Click Tx Mute for the primary Tx online RAC, then click Send. This
immediately mutes the Tx to simulate loss of signal to the remote end. The
remote Node commands a local Tx switch to the standby RAC (secondary
RAC Tx).
4. Confirm service is restored within 20 seconds. At this point the secondary
RAC is online for Tx and Rx.
A variable guard time operates to prevent silent Tx switch oscillation. When the
guard memory is at zero, a switch typically occurs within 3 seconds. If LOS
remains, it switches again after a 5 second guard time. If LOS remains, switching
continues but with a doubling of the guard time on each successive switch, to a
maximum 320 seconds. When normal link operation is restored (no further switch
events), the guard time decrements in reverse time order.
5. Remove the Tx Mute on the primary RAC, and apply to the secondary RAC.
6. Confirm service is restored within 20 seconds. At this point the primary RAC
is online for Tx and Rx.
7. On completion of the tests ensure the remote loopback is disabled, or will
time-out.
8. Use the System/Controls screen to return to default online status (primary
RAC Tx and secondary RAC Rx), and if an unequal coupler is used with a
hot-standby installation, check that the online Tx is selected for the low-loss
side.
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