 within a TMN The Telecommunication Management Network 16/17 The information architecture describes the nature of information which needs to be exchanged between the functional building blocks. The physical architecture of TMN describes the interfaces which have to be implemented, along with examples of physical compo- nents which make up the TMN. 16.8.1.1 The TMN functional architecture The TMN functional architecture is based on a number of functional building blocks which enable a TMN to perform its application functions. They consist of principle blocks, such as the Operations Systems Function (OSF) and the Work Station Function (WSF), and complementary blocks, such as the Data Communication Function (DCF), the Mediation Function (MF) and the Q Adaptor Function (QAF). Some of these blocks are only partly within TMN, as explained later and illustrated in Figure 16.19. The Operations Systems Functions (OSF) processes information to support and control the realisation of various telecommunication management functions. Many types of OSFs are realisable, depend- Figure 16.19 The TMN function block ing on the TMN, and can range from business, customer, service, network and basic levels of abstraction. Business OSFs are con- cerned with the management and co-ordination of the total business or enterprise. Service OSFs usually provide the interface to cus- tomers, and are primarily involved in service aspects of the network. some telecommunication functions which do not form part of TMN, The network OSFs cover the realisation of the network, based on but which are represented to it by the NEF for purposes of manage- TMN application functions, by communicating with the basic ment. Hence this function is shown partly outside the TMN in OSFs. In small networks these basic OSFs may not be present and Figure 16.19. then the network OSFs need to communicate with the Network The Work Station Function (WF) is responsible for providing the Element Functions or directly with the Mediation Functions. user with the means to inte