ed between OSF, QAF, MF and the principles of managed objects and their relationship to real NEF. There are qx reference points between two MFs, or between resources. The concepts of attributes and the concept of manager an MF and a QAF or NEF. There are q3 reference points between and agent manager are also described, as in Figure 16.13. OSFs, or between an OSF and a NEF or QAF or MF. q3 interfaces are very communicative. Less intelligent functions need to use one or more mediation functions, via qx interfaces, to allow them to be 16.8.1.3 TMN physical architecture controlled using a q3 interface. The f reference points are those located between the WSF and Figure 16.21 illustrates a simplified example of the physical archi- OSF or between the WSF and the MF, via the Data Communications tecture for a TMN. The Operations System (OS) is a stand alone Function (DCF). system which performs the Operations System Functions. The The X reference point provides the interface between OSF func- Mediation Device (MD) performs the Mediation Functions. MDs tional blocks within different TMNs, or the equivalent functions in can be implemented as a hierarchy of cascaded devices, as in Figure a non-TMN system. 16.20. The Q Interface Adapter (QA) is the device which network OPERATIONS SYSTEM X/F/Q3 WORK- DATA COMMUNICATION STATION NETWORK (DCN) OPERATIONS SYSTEM DATA COMMUNICATION NETWORK (DCN) Q INTERFACE NETWORK Q INTERFACE NETWORK ADAPTOR (QA) ELEMENT ADAPTOR (QA) ELEMENT Figure 16.21 Simplified example of the physical architecture for a TMN The Simple Network Management Protocol 16/19 elements (NEs) without a TMN interface connect to, using the m The Q3 interface is intended to connect MDs, QAs, NEs (contain- interface point. QAs may incorporate mediation functions, therefore ing MF) and OSs to OSs via a DCN. the interface they present to the TMN may be Q3 or Qx. The F interface is applied at f reference points. When a F interface The Data Communication Network (DCN) is the communication connects workstations remotely to the 