Cisco ASR 9000 Serie

Figure 1: ALDEMS Component Communications, on page 3 illustrates the relationship between the
components that constitute ALDEMS.
Figure 1: ALDEMS Component Communications
Correlator
The correlator receives messages from system logging (syslog) helper processes that are distributed across
the nodes on the router and forwards syslog messages to the syslog process. If a logging correlation rule is
configured, the correlator captures messages searching for a match with any message specified in the rule. If
the correlator finds a match, it starts a timer that corresponds to the timeout interval specified in the rule. The
correlator continues searching for a match to messages in the rule until the timer expires. If the root case
message was received, then a correlation occurs; otherwise, all captured messages are forwarded to the syslog.
When a correlation occurs, the correlated messages are stored in the logging correlation buffer. The correlator
tags each set of correlated messages with a correlation ID.
For more information about logging correlation, see the Logging Correlation, on page 4 section.Note
Cisco ASR 9000 Series Aggregation Services Router System Monitoring Configuration Guide, Release 4.2.x
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Implementing and Monitoring Alarms and Alarm Log Correlation
Alarm Logging and Debugging Event Management System