This Recommendation i International Standard defines the Summarization Function. The Summarization Function is a Systems Management function which may be used by an application process in a centralised or decentralised management environment to interact for the purpose of systems management, as defined by the OSI Management Framework, CCITT Rec. X.700 I ISO/IEC 7498-4. This Recommendation I International Standard defines a function which consists of generic definitions and services. This function is positioned in the application layer of the OSI reference model (CCITT Rec. X.200 I ISO 7498) and is defined according to the model provided by ISO 9545. The role of systems management functions is described by CCITT Rec. X.701 I ISO/IEC 10040. The Summarization Function specifies methods to observe and report attribute values. It also specifies methods for reporting statistics based on attribute values, all observed at the same time. These attribute values and statistics provide summary information concerning a set of managed objects and their attributes at one or more distinct points in time. The statistics are calculated across managed objects, not over time. This Recommendation I International Standard — identifies the set of requirements satisfied by the function; — provides a model for the behaviour of the summarization objects; — specifies the management requirements of the function and how these are realised by specification of managed objects and their behaviour; — specifies the mapping of these services onto the CMIS services; and — specifies the abstract syntax of the parameters of the MAPDUs that will be used to refer to managed objects and their characteristics. This Recommendation I International Standard — does not define the nature of any implementation intended to provide the Summarization function; — does not specify the manner in which management is to be accomplished by the user of the Summarization function; — does not define the nature of any interactions which result in the use of the Summarization function; — does not specify the services necessary for the establishment, normal and abnormal release of a management association; — does not define the interactions which result by the simultaneous use of several management functions; — does not define connection establishment or authorisation requirements for the use of these functions or for any associated activity; and — does not preclude the definition of further metric object classes to provide measurements for inclusion in the function.