Unlike a tactical or bottom-up approach, implementing a top-down approach is driven by the needs of the business. The idea of a top-down approach is not a new concept, but process definition and best practice guidelines, such as ITIL and Cobit, have provided a strong framework that corporations have recently used to make fundamental changes in the way IT conducts itself in alignment with the business.

The top-down approach begins by understanding the company's current and future goals and objectives. The IT department usually has a good idea of the current and near-future business model and ideas of what is to be expected in the near-term. However, future business objectives are not usually distributed outside the realm of the business owners. Future business objectives are a critical piece of the plan, especially if big changes are forthcoming. Pursuing a top-down approach requires a lot of up-front work and coordination between business owners and IT. Research is required that involves the collection of detailed information about your business goals, services, and the various service offerings both currently available and planned for the future. The main objective of the top-down approach is to understand your business and align IT with the business strategy. This approach allows the business to drive the actions of those that deliver and support the business critical services.

There are many things to do when implementing a typical top-down approach to managing service levels:

• Identify all of the major services that support the organization. Your list should include services delivered for both internal and external users. Internal services can include email, telephone service, business applications, and requested services. External services would include services delivered to users or customers outside your organization.
• Define the service offerings based on customer expectations. A business service can be delivered to various user communities, and these communities might have different needs. Gather supporting financial information, including potential revenue and additional IT expenses where applicable. Some of this information can be maintained in a service catalog application or simply in a spreadsheet.
• Identify all responsible parties for the business services and their service offerings. Responsible parties include representatives of the service user community, those supporting the service, service owners, and business relationship managers.
• Assemble all information that defines contractual agreements between the responsible parties. These agreements might be well documented or could be a simple unwritten expectation of the users.
• Review the agreements to make sure they make sense to the customer receiving the service, as well as the IT providers. An example of a poor financial match is where the customer expects sub-second response times for an application but might not be able to afford to pay for the infrastructure required in order to meet their expectations.
• Quantify a per minute or per hour cost associated with the unavailability or degradation of each service offering. Understanding these cost calculations helps later in the process to prioritize IT staff actions.

After you have documented each of these topics, you are on your way to aligning your service providers to your business. Understanding the needs of your business, the users you are serving, and the future business direction are all critical to establishing a solid strategy around managing service levels.