Service Design and Service Level Management
This domain tests whether you can design services that are fit for purpose and fit for use, and whether you can define service levels that are measurable and enforceable. Expect the four dimensions of service management, service catalogue design, SLA structure and the SLA/OLA/UC hierarchy.
Core rules and concepts
- Design considers four dimensions: organisations and people; information and technology; partners and suppliers; value streams and processes.
- Service level management negotiates, agrees, monitors and reports service levels. It also manages reviews and improves levels over time.
- An SLA is with a customer. An OLA is an internal agreement supporting an SLA. An underpinning contract is with an external supplier.
- Service levels must state scope, measurement method, reporting period, exclusions and remedies. A percentage without these is not an SLA.
- Design coordination ensures consistent outputs across design activities and avoids conflicting designs.
Worked example
A service promises 99.9% availability in a 30-day month. That allows 43.2 minutes of unavailability (43,200 minutes x 0.001). But the figure is meaningless until you define the measurement point, whether planned maintenance is excluded, whether partial degradation counts, and how users report unavailability. If the SLA is measured at the server but users fail at the authentication layer, the service appears available while the customer experiences an outage. The reasoning is that service level targets must align with customer-visible outcomes and with the OLAs and contracts beneath them.
Traps
Writing SLAs without a measurement method; setting OLAs that do not support the SLA; quoting uptime without scope or window; overpromising warranty to win a design decision; ignoring supplier contracts in the service level hierarchy.