Frame Relay - for Faster and More Efficient Data Communications ...

37Fig. 5Transport Processing Functions, Transport Entitiesand Reference PointsTRPFSTransport Reference PointTransport Processing Function or TransportEntityManagement Reference PointTelecommunication network functions andresources appear in all the networksshown in Fig. 4. Each network can consistof several layers, each of which can bemanaged individually by a Manager-AgentProcess. 3 The resources and their propertiesare represented in a standardised wayas Managed Objects in databases.Management methodologyNetwork management requires the selectionof a TMN Management Service - i.e.a distinct task for an operator - which involvesseveral TMN Management Layers- i.e. the area of application of the task,Fig. 2. The task requires a functional analysisleading to Resources that are suitablefor management. The Resources aredescribed in the functional modelling process.The information modelling process isbased on the management tasks and organisationof the management provider.The selection of a particular TMN ManagementService and related TMN ManagementLayers leads to the selection of TMNManagement Service Components andTMN Management Functions. TMN ManagementFunctions are performed onManaged Objects. 3The information modelling process specifieswhich Managed Objects are neededto perform the desired management tasks.The functional modelling process leads tothe Manageable Recources offered by thenetwork. Harmonisation of these requirementsnormally leads to iterative processes.The Information Model contains all data relatedto the Managed Objects, their relationshipsand naming structure, as seenacross a particular management interfacebetween the managing and managedsystems. In the Information Model, whencompleted, all required Managed Objectsappear in a standardised form.The process of deriving transport networkManaged Objects consists of functionalmodelling and information modelling. Inthese analyses, a given physical transmissionnetwork supports a transport network.Each transport network contains layers definedby a characteristic signal. 2 Connectionsand Connection Points carrying thecharacteristic signal are determined foreach transport network layer. This processleads to a detailed specification of managementaspects of the Network Elementsforming the transport network (NetworkElement View). Each transport networklayer can be partitioned into various geographicaland administrative regions,which offers various degrees of detail inthe network views.The management of Trails and Connectionsis based on Resources in the vicinityof the end points of Trails and Connections.The anomaly detectors and controllabledevices in the telecom equipment arerepresented in the Functional Model asproperties and Resources; these in turncorrespond to transport network ManagedObjects in the Information Model. The followingchapters go into more detail concerningfunctional modelling and informationmodelling for transport network-relatedTMN Management Services.Functional modellingThe physical implementation of digital telecommunicationnetworks comprisesequipment such as- switching matrices- modems and muldexes- line, radio and satellite systems- transmission media for line systems andinterfaces belonging to the transmissionnetwork.Functions performed by the above-mentionedequipment include- cross connection and switching- multiplexing and demultiplexing- signal conversion between physicaltransmission media and interface cables- signal transmission via physical media.The functions of a telecommunication networkcan be modelled with the aid of theERICSSON REVIEW No. 1-2,1992