anagement dimension (M). Through these definitions, interfaces in the M dimension exist in nodes of the traffic system, where the resources to manage exist. Therefore, the boundary between the management plane and traffic plane on the one hand, and between the management system and traffic system on the other, do not coincide, as depicted in Fig. 1.32 for an imaginary node of a traffic system (note that we call managed sys- tem "traffic system", to avoid confusing the two systems). Traffic system users Management layer AMF protocol T protocol protocol Operators Other msCP protocols nodes Traffic system node Management system Fig. 1.32 The boundary between traffic plane and system, and management plane and system Figure 1.32 shows that a management plane consists of two parts: a (probably) rather large set of autonomous management functions (AMF) and a manage- ment layer that runs on some suitable connectivity strata, one of which must be common for the two systems in order to support communication between adapta- tion functions (AF) and the operations system functions (OSF). The boundary between planes consist of two relations denoted MR and Mc in Sect. 1.4.1.2. In a model, these relations appear as control points and connectiv- ity service points, that we denote mrCP and CSPM respectively. 1.4 Modeling Network Systems in AMLn A traffic system node always includes an interface function to the management system (called AF in the model). These functions define the interface between the two systems, normally in terms of managed objects (MO). Managed objects create a view of resources ("R" in the model) in a traffic sys- tem node. This view is constrained to properties of resources that are accessible. A managed object hides the actual implementation of resources, and thereby of their interfaces (mrCP), since this interface is of concern only to implementors of traffic system nodes. The management plane may also include many autonomous management func- tions (AMF) that perform their tasks without control from the man