Apsb; Apscdfltk - Cisco ONS 15327 User Documentation

Chapter 14 Alarm Troubleshooting
have its OC-N port in service. The upstream node often reports a LOS or has an out-of-service port. The
AIS-V clears when the primary alarm is cleared. The node with the out-of-service port may not report
any alarms to indicate it is at fault.
An AIS-V indicates that an upstream failure occurred at the VT layer. The VT, or electrical layer, is
created when the SONET signal is broken down into an electrical signal. For example, it can be raised
when an optical signal comes into an ONS 15327 OC-N card. If this optical signal is demultiplexed by
the ONS 15327, and one of the channels separated from the optical signal is then cross connected into
the XTC ports in the same node, that ONS 15327 reports an AIS-V alarm. An AIS-V error message on
the electrical card is accompanied by an AIS-P error message on the cross connected OC-N card.
Procedure: Clear the AIS-V Condition on the XTC-14 Card or XTC-28-3 Card
Check upstream nodes and equipment for alarms, especially LOS and out-of-service ports.
Step 1
Correct the upstream alarms.
Step 2

14.4.5 APSB

•
The channel byte failure alarm occurs when line-terminating equipment detects protection-switching
byte failure in the incoming automatic protection switching (APS) signal. This happens when an
inconsistent APS byte or invalid code is detected. Some older, non-Cisco SONET nodes send invalid
APS codes if configured in a 1+1 protection scheme with newer SONET nodes, such as the ONS 15327.
These invalid codes raise an APSB on an ONS node.
Procedure: Clear the APSB Alarm on an OC-N Card
Examine the incoming SONET overhead with an optical test set to confirm inconsistent or invalid K
Step 1
bytes.
If corrupted K bytes are confirmed and the upstream equipment is functioning properly, the upstream
Step 2
equipment may not interoperate effectively with the ONS 15327. For ONS 15327 protection switching
to operate properly, the upstream equipment may need to be replaced.

14.4.6 APSCDFLTK

•
The default K byte received (APSCDFLTK) alarm occurs when a BLSR is not properly configured. For
example, it is raised when a four-node BLSR has one node configured as UPSR. A node in a UPSR or
1+1 configuration does not send the two valid K1/K2 APS bytes anticipated by a system configured for
BLSR. One of the bytes sent is considered invalid by the BLSR configuration. The K1/K2 byte is
monitored by receiving equipment for link-recovery information.
The alarm can also be caused when a new node is added but a new ring map has not been accepted.
Troubleshooting for APSCDFLTK is often similar to troubleshooting for BLSROSYNC.
June 2002
Minor, Non-Service-Affecting
Minor, Non-Service-Affecting
Cisco ONS 15327 User Documentation, R3.3
Alarm Procedures
14-11