 between the management and the traffic system, managed objects rep- resent real traffic system resources In this model we have used the AMLs notation for the relation between abstract machines and abstract objects ("managed objects," MO here). Each MO type defines its own operations, as parts of its interface specification. The individual MOs exist in an AF. In communication over the mpCP, each MO instance has a In TMN, these mpCPs are defined as the CMIS/CMIP protocol. The corresponding protocol in the Internet is SNMP (more about that later) 5.2 Two Systems and Two planes unique identity (the "object identifier" in AMLn invokes). The realization of MOs in an AF are object instances that can handle actual mrCPs. The model also makes the distinction between MOs and real resources (R). This distinction allows for a single resource to be represented by several different MO types (or the other way around), i.e., there is not necessarily a one-to-one corre- spondence between an R and an MO. For example, a T-RE table (a single physical resource) may define route endpoints that are realized by two different connectivity strata, and therefore have different types of addressing parameters. This would require definition of two different MO types, both associated to the same real resource. It is the role of an MO implementation to relate an operation defined by an MO specification to invocations on some part of a real resource. AFs and MOs are therefore elements that must be realized by implementors of traffic systems. So far, our discussion tells only part of the management story, however. In standardized management concepts (such as TMN and SNMP), all specific man- agement functions are regarded as centralized, i.e., OSFs. In AMLn we also regard management functions that are not part of the management system as parts of the management plane. We regard these functions as decentralized and call them autonomous management functions (AMF). Examples of such functions are the IP routing protocols (that autonomously maintain r