This paper gives a general overview of the service level management (SLM) approach, which cart offer significant advantage to service providers competing in the current European market. Starting from a theoretical approach, concepts are then applied to telecommunications scenarios focusing on the provision of data services and the Internet protocol (IP). Major concepts related to service level agreements (SLAs) and SLA management systems are analysed in, greater detail defining hom such concepts can be applied to IP networks. Finally some details are given concerning possible parameters to be applied to the provision of IP services, including both permanent and switched services.