The "Services Specification" section of the SLA will contain a Service Description. Each Service will be linked to the statement of the business need and the reasons for the SLA. Where there are several business needs and several Services within a single SLA, each business need should be linked to all of the Services on which it depends.

Figure 71.1: Needs and services

It is worth attempting to link each Service with a unique business need, so that the following view is preferable to the one above.

Figure 71.2: Multiple needs and services

Consider the situation where Service A and Service B are to be provided by two separate service providers. If the provider of Service A fails to provide that Service adequately, then the needs (or objectives) called Need 1 and Need 2a will not be satisfied. This will have no impact on the customer's ability to measure the other provider's contribution to Need 2b. In the original scenario, with both providers attempting to satisfy Need 2, difficulties could arise in measuring the effectiveness of one of the providers if the other one failed.

In this second scenario, it would be preferable if the two Services were the subjects of separate SLAs.

Figure 71.3: Separation of needs and services