ISO/IEC 20000 defines a set of management processes that form a service management system which can be used for the effective delivery of services to the business and its customers. The standard is applicable to all types and sizes of service provider.
ISO/IEC 20000 is aligned with and complementary to the process approach defined within ITIL, and is supported by other similar control approaches, such as COBIT. ISO/IEC 20000 is a standard which means it is prescriptive in what you can or cannot do in terms of the processes it covers. It is based on the ITIL framework, so shares many areas in common, but the standard will set out what must be achieved, instead of providing guidance which can be adapted.