Specifications

1-72
Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Chapter 1 Alarm Troubleshooting
Warning Invisible laser radiation may be emitted from the aperture ports of the single-mode fiber optic
modules when no cable is connected. Avoid exposure and do not stare into open apertures.
Caution Always use the supplied electrostatic discharge wristband when working with a powered ONS 15454.
Plug the wristband cable into the ESD jack located on the lower-right outside edge of the shelf
assembly.
Procedure: Clear the SF-L Condition on an OC-N Card
Step 1 Using an optical test set, measure the power level of the line and ensure it is within the guidelines.
Step 2 Verify that optical receive levels are within the acceptable range.
Step 3 Clean the fibers at both ends for a line signal fail:
a. Clean the fiber according to local site practice.
b. If no local practice exists, use a CLETOP Real-Type or equivalent fiber-optic cleaner and follow the
instructions accompanying the product.
Step 4 Verify that single-mode fiber is being used.
Step 5 Verify that a single-mode laser is being used at the far-end node.
Step 6 If the problem persists, the transmitter at the other end of the optical line may be failing and need
replacement.
1.3.106 SF-P
• Not Alarmed (NA) (Condition)
The quality of the signal is so poor that the BER on the incoming optical line passed the signal failure
(SF) threshold. The ONS 15454 sets the BER threshold for SF from 10
-5
to 10
-3
. Signal failure is defined
by Telcordia as a “hard failure” condition. SD and SF both monitor the incoming BER error rate and are
similar alarms, but SF is triggered at a higher BER than SD.
SF-P causes a switch from the working card to the protect card at the path (STS) level. A path or STS
level SF alarm travels on the B3 byte of the SONET overhead. The ONS 15454 detects path SF on the
STS level, not the VT level.
SF causes a card to switch from working to protect at either the path or line level. The SF alarm clears
when the BER level falls to one-tenth of the threshold level that triggered the alarm. A BER increase is
sometimes caused by a physical fiber problem, including a poor fiber connection, a bend in the fiber that
exceeds the permitted bend radius, or a bad fiber splice.
Invisible laser radiation may be emitted from the aperture ports of the single-mode fiber optic modules
when no cable is connected. Avoid exposure and do not stare into open apertures.
Always use the supplied electrostatic discharge wristband when working with a powered ONS 15454.
Plug the wristband cable into the ESD jack located on the lower-right outside edge of the shelf assembly.