Identifying Availability Requirements

Many organizations have predefined service levels for IT applications and services. Lync Server 2013 often falls into many different service-level definitions, depending on the workloads deployed. Table 15.1 provides an example of service levels in a typical enterprise organization.

Table 15.1. Lync Service Levels

The service levels described in Table 15.1 represent a generic overview of common Lync service levels. These levels also translate to detailed requirements for availability. Availability is presented based on the percentage of downtime throughout the entire year. Services with a high service level are often targeting 99.999% availability. However, it is important to understand what those percentages actually translate to in order to guide businesses down the right path for a highly available Lync Server system.