A G-CPN Approach for M4 Network-View Interface Managed ObjectsEntities ModelingDalton D.S. Guerrero , Aldenor F. MartinsAngelo Perkusich and Jorge C.A. de FigueiredoDepartamento de Sistemas e Computac ¸˜ aoDepartamento de Engenharia El´ etricadalton, abrantes @dsc. ufpb. br,Universidade Federal da Para´ ?baCaixa Postal 1010558109-970 - Campina Grande - PB - BrazilFone: +55 83 310 1135 Fax: +55 83 310 1015aald, perkusic @dee. ufpb. brAbstractThe difficulty of managing computer networks resources is be-comingincreasinglycomplexas networksaddmore components,more users and functions. In the case of Network ManagementSystems (NMS) and in particular those based on ATM, the needto formally specify and design managed entities is of particularinterest. In this paper we introduce a Petri net object based ap-proachnamedG-CPNtothemodelingofM4 network-viewinter-face managed objects entitiesinATM networks. G-CPNis anob-ject based Petri net withits foundationderived from CPN and G-Nets formalisms. G-CPN system is a set ofcooperating G-CPNswhich main purpose is the formal and executable modeling andspecification of complex distributed software systems. We alsopresent a systematic way to obtain an equivalent CP-net from agiven G-CPN system, allowing its analysis from the utilizationofthe already developed computer tools for CP-netsKeywords: Coloured Petri Nets, Object-Orientation, FormalSpecification, Asynchronous Transfer Mode, M4 interface.1IntroductionA Network Management Systems (NMS) architecture might beorganized around functions and function blocks, describing theactivities that a NMS performs in its management responsibil-ities. Any pair of function blocks that exchange informationbetween them are separated as reference points. The referencepoints delineate the boundaries between function blocks. Thereference points define protocol suites and protocol messagesthat are used to exchange information between NMS functions.The interfaces are based on object oriented concepts [1].In a NMS we can define three key elements: the manag-ing system, the managed system and the managed resources. Amanager, in the managing system, can interact with the managedsystems through agents, and managed objects. Managed objectsare abstractions of real resources into objects which is a repre-sentation of real resources for the purpose of systems manage-ment. These managed objects in a NMS database are organizedaround an entity named Management Information Base (MIB),[11]. Also, in this context a manager, could be a human user, asoftware process or hardware responsible to carry out managingactivities.Withtheincreasing numberand complexityoftheresourcesin a computer network it is more and more important to rely onformal methods to model the managed objects. In this work theformalization basis relies on Object Managed Entities (OME) ofM4 Interface informally described in [3]. These OME constituteparts ofthe ATM Network NMS MIB.Inorderto formally model theM4 interface we introduceG-CPN andG-CPN systems, an objectbased Petri net withits foun-dationonColouredPetriNets[8] andG-Nets[5, 6, 10, 9]. G-CPNsystems are constructs ofconcurrent, cooperating and loose cou-pling objects, which main purpose is the formal and executablemodeling and specification ofcomplex distributed software sys-tems. G-CPN allows the software system specification to be de-veloped in an incremental and non-monotonic way. G-CPN for-mal definitions allows the use ofCP-nets insideG-CPN Moduleswith almost no modification.The paperis organized as follows: Insection 2 we introducethe basic concepts of the M4 interface. In Section 3 we presentthe definition of G-CPN module. In Section 4 G-CPN systemsare detailed. In Section 5 we present the modeling and analysisof the managed entities. Finally, in Section 6 we conclude thepaper.2M4 Network-View InterfaceThe AF-NM-0058.000document fromthe ATM Forum[2] spec-ifies functional requirements for an interface capable to manageindividualATM NetworkElements (NEs), named M4, theroleofthis interface can be understood in the light ofThe ATM ForumManagement Interface Reference Architecture as found in [3].The M4 has two views: The Network Element(NE) View[2] is concerned with managing ATM NEs. The Network Viewis concerned with managing aggregate NEs as one or more sub-networks. Its logical architecture is shown in Figure 1.networkmanagementfunctionmanagementfunctionnetwork elementnetworkmanagementfunctionsubordinatenetwork element view - evnetwork view - nvFigure 1: Network viewIn the Figure 1 it is shown how the network managementuses the network view to communicate with a subordinate net-work management function. It has, for completeness, a net-work element view (NE-view) between a subnetwork manage-mentfunctionandtheelementmanagement function. A NetworkManagement System (NMS) may use managed entities from thenetwork view, the network element view, or both.The sight dis-1
