Service level criteria (SLCs) are used to monitor for activities that either do or do not occur. Whereas, rules can act on only the events that do occur.

They monitor processes based on performance objectives: the process or process step/activity executes or fails to run within a certain time frame or for a specified duration. Processes can include Sterling Connect:Direct® Processes, Sterling B2B Integrator business process activities, and the movement of data into and out of Sterling Connect:Enterprise® mailboxes. When the conditions in an SLC occur or fail to occur, an SLC event is generated. You can set up rules based on SLC event message IDs that start actions, such as generating an alert. SLCs cannot generate alerts without rules.

For example, IBM® Sterling Control Center Monitor monitors FTP Puts from a bank to ensure delivery to a partner within a certain time frame (SLC performance objective). When all outbound files are sent, an outbound rule is triggered when transfers are completed successfully within the specified time frame. An email notification is sent.

When you are dealing with SLCs, the process differs as shown in the following figure:
Image shows the flow of an SLC process.

The SLC process begins with an event. This event is processed by the metadata and visibility services. The event is input for the SLC, or performance objective. The SLC triggers an SLC-type event which generates an SLC event message ID and tags the event with its DVG. The SLC-type event triggers a metadata rule which triggers a rule. This rule is specified by the SLC event message ID. The rule initiates an action, such as a GUI alert, email notification, SNMP trap, or OS or server command.