s entities shared across two or more domains. As a result these busi- ness entities are not owned by any particular domain. The GB922 document of TeleManagement Forum covers the business view of SID and GB926 covers the system view of SID. 24.3 Common Information Model (CIM) The CIM is an information model developed by DMTF. It uses object-oriented constructs and design in creating information models. The hierarchical, object- oriented architecture in CIM makes it easy to depict complex interdependencies. The CIM schema provides the actual model descriptions and captures notions that are applicable to all common areas of management, independent of implementations. The CIM is a method for describing resources and their interactions in a het- erogeneous IT environment. It is a technology neutral model for describing and Information Models accessing data across an enterprise and is not associated to a specific vendor. CIM can be used for modeling actual and virtual resources. Another important standard, Web-based enterprise management (WBEM) also developed by DMTF is commonly used with CIM. While CIM defines the information model, WBEM defines the protocols used to communicate with a particular CIM implementation. CIM provides interoperability at the model level and WBEM provides interoperability at the protocol level. WBEM standards can be used to develop a single set of management applications for a diverse set of resources. DMTF has defined specifications on the schema and operations with CIM. This section is intended to give an overview on the CIM concepts. Some of the basic building blocks in CIM are: 1. CIM specifications: The common information model specification describes an object-oriented meta-model based on the unified modeling language. The details for integration with other management models are defined in CIM specification. Data elements are presented as object classes, properties, meth- ods, and associations in CIM specifications. CIM applies the basic structuring and conceptualization techniques of 