This Recommendation | International Standard defines a systems management function which may be used by an application process in a centralized or decentralized management environment to interact for the purpose of systems management as defined in CCITT Rec. X.700 | ISO/IEC 7498-4. This Recommendation | International Standard defines the usage metering function and consists of service and generic definitions. It is positioned in the application layer of ITU-T Rec. X.200 | ISO/IEC 7498-1 and is defined according to the model provided by ISO/IEC 9545. The role of systems management functions is described by CCITT Rec. X.701 | ISO/IEC 10040. This Recommendation | International Standard: — establishes user requirements for service definitions needed to support the usage metering function; — establishes models that relate the service provided by this function to the user requirements; defines the service provided by the function; — specifies the protocol that is necessary in order to provide this service; — defines the relationships between the service and the operations and notifications for usage metering managed objects; — defines the relationships with other Systems Management functions; — specifies conformance requirements; — defines generic managed object classes, packages, attributes, operations types and notification types, documented in accordance with guidelines for the definition of managed objects; — specifies compliance requirements placed upon other standards which make use of these generic definitions. This Recommendation | International Standard neither defines nor specifies: — the interactions which are the consequence of the use of usage metering facilities; — connection establishment or authorization requirements for the use of these facilities; — which usage metering attributes, management operations and notifications are to be incorporated when defining accounting for the use of specific OSI resources or other resources; — any procedures for the subsequent use of usage data, whether gathered from a usage metering data object or a log; in particular, procedures for using this data for filing, auditing, correlation or for combining usage data are excluded; — the process by which usage data, gathered from a managed object, are used to form usage metering records in a log; — the usage gathering process within the accountable resource; — the charging process and the billing process.