The present document is part of a TS-family covering the 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Telecommunication Management; as identified below: The present document is part of a set of specifications, which describe the requirements and information model necessary for the standardised Operation, Administration and Maintenance (OA&M) of a multi-vendor 3G-system. During the lifetime of a 3G network, its logical and physical configuration will undergo changes of varying degrees and frequencies in order to optimise the utilisation of the network resources. These changes will be executed through network configuration management activities and/or network engineering, see TS 32.600. Many of the activities involved in the daily operation and future network planning of a 3G network require data on which to base decisions. This data refers to the load carried by the network and the grade of service offered. In order to produce this data performance measurements are executed in the NEs, which comprise the network. The data can then be transferred to an external system, e.g. an Operations System (OS) in TMN terminology, for further evaluation. The purpose of the present document is to describe the mechanisms involved in the collection of the data and the definition of the data itself.

The present document describes the measurements of IMS. 3GPP TS 32.401 describes Performance Management concepts and requirements. The present document is valid for all measurement types provided by an implementation of an IMS network. These may be measurement types defined within the present document, measurements defined within other standards bodies, or vendor specific measurement types. Only measurement types that are specific to IMS network are defined within the present documents. I.e. vendor specific measurement types and measurements related to "external" technologies used in IMS network, such as ATM or IP, are not covered. Instead, these could be applied as described by the other, "external" standards bodies (e.g. ITU-T or IETF) or according to manufacturer's documentation. The definition of the standard measurements is intended to result in comparability of measurement data produced in a multi-vendor network, for those measurement types that can be standardised across all vendors' implementations. The structure of the present document is as follows:

• Header 1: Network Element (e.g. measurements related to CSCF);
• Header 2: Measurement function (e.g. Registration related measurements);
• Header 3: Measurements.