Bottom-up approach
The bottom-up approach is a more traditional way to manage your service levels and is more comprehensive than the tactical approach. A bottom-up approach focuses on managing service levels from an IT point of view, rather than a business view. IT is the focal point for how service levels are designed, deployed, and administered.
Most IT departments are divided between teams tasked with delivering a service and teams that provide support to the service. This division between service delivery and service support can create interesting points of conflict, as each group has a different view of what managing service levels means and what should be done to fulfill these service levels. The service support team focuses on how well user issues are serviced, how well questions are answered, and any changes in the supporting environment. The service delivery team focuses on the infrastructure itself, addressing transactional throughput and response; network, system, application and database performance; and infrastructure uptime, as being critical to a business service's success. Both approaches are correct, and each is an important part of delivering an end-to-end business service. However, these teams rarely coordinate their efforts.
IT silos develop in the bottom-up approach, and this separation is re-enforced by the different viewpoints. The service delivery group purchases tools to track and report on the metrics they think are important, and the service support group takes a similar path. In the end, business owners are left to struggle and make sense out of the multiple service level reports received from each of the teams, detailing how well each silo met customer expectations. In times of service outages or degraded performance, blame between the teams can happen, creating confusion and ultimately, dissatisfied customers. In some companies, service delivery might not be a single harmonious group but might consist of many different teams that are organized around infrastructure layers such as network, servers, and applications. A similar story might unfold with service support teams aligned with different service support processes, like incident, problem, change, and asset management.
The bottom-up approach is very IT-centric, where Service Level Agreements (SLAs) are in silos based on IT teams, service type, or geographic region. These SLAs are often represented in terms well understood by IT but rarely translate into any true business need.