rpret the information coming from the The Mediation Function (MF) is responsible for adapting, filter- TMN. It also includes support for the interfaces to the user, these ing and condensing information which passes from the NEFs, and aspects being considered to be outside the TMN. The WSF contains sometimes from the QAFs, to suit the requirements of the OSFs. the Presentation Function (PF) which provides the user with human The Network Element Function (NEF) communicates with the readable displays and with a method of data entry, such as a TMN in order that it may be monitored and controlled. It includes terminal. Figure 16.20 Example of the TMN functional reference model and classes of reference points 16/18 Network management The Q Adaptor Function (QAF) provides the translation between The g reference point provides the interface between the worksta- a TMN interface and a proprietary or non-TMN interface, this latter tion and the human user. It conveys TMN information but is con- part being outside the TMN in Figure 16.19. The QAF is therefore sidered to be outside the TMN. Similarly an m reference point is used to connect those network elements which do not support TMN considered to be located outside the TMN. It is situated between the interfaces to a TMN. QAF and a managed entity which does not conform to TMN. Within the TMN the concept of reference points is introduced, these being used to define the boundaries between the management function blocks, as in Figure 16.20. Reference points describe the 16.8.1.2 TMN information architecture service interface between two management function blocks and identify the information which passes between them. There are The information architecture for TMN is based very closely on that three classes of TMN reference points (q, f and x) and two classes of OSI, these principles being developed further by TMN within Recommendation M.30. of non-TMN reference points (g and m). An object oriented approach is used throughout. M.30 also defines The q reference points are locat