Administrator Handbook Table of contents version française

Introduction to Quality Of Service and Service Level Agreement

The SLA Report Center plugin of LoriotPro provides control over the quality of service of your information system and performs checking on the current metrics of any service level agreements (SLA).

This short introduction explains the concepts and the terminology attached to the measurement of the quality of service.

First, let’s explain the 3 terms that we will use frequently in this documentation, QOS, SLM and SLA

What is Quality Of Service (QOS) of an information system ?

The quality of service of an information system consists of few criteria for an end user.

For the network and system administrators the quality of service implies many technical constraints and many more markers to monitor. Among these markers there are always the global need of availability and performance of the applications and systems but to guaranty these two conditions, administrator should monitor and  measure technical indicators like throughput level, jitter, delay, response time, new feature introductions, scalability requirements, new application introductions, manageability, security and even cost.

What is Service Level Management (SLM) ?

Service level management provides goals for all information system personnel and can be used as a metric in the quality of  service measurement.

Service level definitions can be used as a tool for budgeting network resources and as evidence for providing enhanced QoS. Service level management  also provide a way to evaluate the performance of external services provided by ISP, ASP and network operator.

Without a quality of service definition and measurement, the organization does not have clear goals. Service satisfaction may be governed by users with little differentiation between applications, server/client operations, or network support.  

What is Service Level Agreement (SLA) ?

The Service Level Agreement (SLA) define the engagements between a supplier and users.  The supplier represents here the computer services of a business or an exterior supplier such as the operators of telecommunications or the ISP.  The users are the personnel of the business or generically the consumers of the furnished service. 
A SLA clearly defines the quality of the services and expresses itself generally in percentages of contractual objectives.  The contract also must define the methods of evaluation and of measure of the quality to avoid the most possible the imprecision. 

By way of example let us take the case where the availability of a service (an application, a network access, etc…) has to be assured 99.5% of the time per week.  A quick calculation allows us to deduce that the service should not be unavailable more than 7.2 minutes during the week.   Over this time we can say that the contract is not respected. 

Now that the concepts are introduced, you will discover that with  LoriotPro and the SLA Report Center Plugin you can setup a true  control of the service quality, by defining service level agreement, by setting up the measure tools on quality indictors and by producing reports of analysis on the quality goals.


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