---
title: Service Level Monitoring Classes
slug: ps/help/en_us/vtm/userguide/service-level-monitoring-classes
docTags: 
createdAt: 2026-08-02T07:48:40.720Z
---

“Service Level Monitoring (SLM) classes” are used to monitor the level of service (response time) that end users of the service are receiving. An SLM class defines a desired response time. It also defines percentage tolerance limits; if the percentage of requests that meet the desired response time falls below these limits, an alert or log message is raised.

You can apply a service level monitoring class to a virtual server by clicking the **Classes** link on the appropriate **Virtual Servers > Edit** page. In the Service Level Monitoring section, select a class from the list and click **Update**. This will cause the virtual server to monitor and log the response times for all of the connections it manages, and raise log+ messages or alerts in the event of service level problems.

Service Level Monitoring is covered in detail in [Service Level Monitoring](docId\:pkG8yK2feDwfsz8jGRMrN).

:::hint{type="info"}
Service Level Monitoring is not available on all Virtual Traffic Manager configurations. If required, it can be obtained via a software or license key upgrade.
:::