Interpreting a Message
This section describes how to interpret a message generated by ELS. Figure 4
shows the message contents.
The information illustrated in Figure 4as well as the ELS logging level information
displayed with the list subsystem command is as follows:

Subsystem

Subsystem

is a predefined short name for a router component, such as a protocol
or interface. In Figure 4, GW identifies the subsystem through which this event
occurred.
Other examples of subsystems include IP,TKR, and X25. On a particular router, the
actual subsystems present depend on the hardware and software configured for
that router. Youcan use the list subsystem command described in this chapter to
see a list of the subsystems on your router.
Enter the subsystem as a parameter to an ELS command when you want the
command to affect the entire subsystem. For example, the ELS command display
subsystem GW causes all events (except the events with ’debug’ logging level)
that occur through the GW subsystem to be displayed.

Event Number

Event Number

is a predefined, unique, arbitrary number assigned to each message
within a subsystem. In Figure 4, 019 is the event number within the GW subsystem.
Youcan see a list of all the events within a subsystem by using the list subsystem
command, where

subsystem

is the short name for the subsystem.
The event number always appears with a subsystem identifier, separated by a
period. For example: GW.019. The subsystem and event number together identify
an

individual

event. They are entered as a parameter to certain ELS commands.
When you want a command to affect only the specified event, enter the subsystem
and event number as a parameter for the ELS command.

Logging Level

Logging level

is a predefined setting that classifies each message by the type of
event that generated it. Use the list subsystem ELS console command to display
the setting of the logging level. Table17 on page 150 lists the logging levels and
types. ERROR, INFO, TRACE, STANDARD,and ALL are aggregates of other
logging level types. STANDARD is the recommended default.
Figure 4. Message Generated by an Event
Using ELS
Chapter12. Using the Event Logging System (ELS) 149