CORBA based approach to the development of an ... - CiteSeerX

CORBA based Approach to the Development of an Advanced Architecture in TINA Service Management System HeaSook Park

0-Hoon Choi Software Systems Lab. Dept. of Computer Science & Engineering KOREA University SEOUL, KOREA. { hspark/pens/baik} 63software.korea.ac.kr

Abstract

Doo-Kwon Baik

but M O is stored not a concentrative repository but various heterogeneous and distributed repositories regionally. Therefore, an application program must have to get needed MO by accessing remote computer in distributed environment. Because different MOs in distributed environment may manage in different hardware and operating system environments, the interface between object-oriented applications and data repositories must have transparency about the different commercial platform tool kit, hardware platform, sorts of data repository, and programming languages. To solve this problem, we propose the advanced architecture which is called OMS(0bject Management System), the applications and OMS are connected by distributed object middleware based on CORBA. In order to efficiently manage MOs are stored in different repositories, we implement MDR (Metadata Registry) by using data element concept. When the object-oriented application is implemented by using OMS, OMS satisfy the interoperable and transparent data interface about MOs. To prove the effectiveness of the OMS, we have implemented the prototype of a subsystem of TINA service management layer.

In order to satisfy the complex and various demands of the customers, telecommunication networks must provide their services rapidly and flexibly, with the support of efficient service and network management systems. To @fill these requirements, TINA has appeared as a concept for the advanced telecominunication system using the itlformation technology such as distributed processing, object oriented modeling. In this paper we will mention some problems of developing applications in TINA service nianagement layer: To solve the problems, we will propose the advanced architecture called OMS (Object Management System), which consist of three managers (Data Manager; Data Access Manager and nietaData Registty Manager). OMS separates the application layer and the middleware such as ODBC and JDBC. And the application layer and OMS are connected by distributed object middleware based on CORBA. Also in order to manage efficiently managed objects stored in different repositories, we have implemented Metadata Registry by using metadata concept.

2. Related Works 1. Introduction

2.1. CORBA based Distributed Object Computing

TINA[ 1][2] has appeared as a concept for the advanced telecommunication system using the information technology such as distributed processing, object oriented modeling. But there are several problems when subsystem using object-oriented technique is implemented. One of the problems is that interface works between realized application programs using its technique and data repository for assurance of internal objects persistency are difficult. In addition, it takes a lot of times to implement applications [3]. In general, an application program needs MO(Managed Object) to manage subsystem which consists of networks

In distributed environment, the study to solve the problem of interoperability is lively in progress by means of meddleware. Wiederhold[4][5] suggested the method for acquisition of knowledge which need particular domain from various resources by using mediators. Neches[6] suggested the proper selection method about various information resources. Fanchitti[7] proposed the Wrapper activation method for efficient processing of existing regacy application. Gravano[8] proposed the selection method of various distributed resources by using already computed information., CORBA based distributed computing architecture

175 1529-4188/01$10.00 0 2001 IEEE

ferent types of controls. So it is difficult to access relevant information from several independent database systems in a distributed environment and present a common interface to the user. Here we propose a practical method to integrate local databases based on metadata registry models. We are using data element concept and metadata registry model for a distributed and heterogeneous database integration, and demonstrate that this model is rich enough to resolve most of the issues in integrating heterogeneous database. And it is suited for management of data object in distributed environment. In this paper we have modeled metadata registry based on a metamodel proposed by ANSI X3.285[11] and ISODEC 11 179[12].

1

I

Figure 1. Network Management Architecture of TINA

is to solve the problems such as interoperability and transparency of applications in distributed environments. ORB (Object Request Broker) takes charge of communication channels about objects and object service provides persistency needing handle objects, concurrency, naming, lifecycle, security and so on[9]. CORBA provides network management systems with convenient tools and independent services to solve the problems such as interoperability, reusability, data consistency.

2.4. Fundamental Concepts of data element In ISO/IEC 11 179, Data element is defined as electronic or written representation of the properties of natural-world object classes and is the smallest unit of data that is shared and held in common[ 121. It is composed of three parts: Object class, Property and Representation. Object classes are the things about which we wish to collect and store data. Examples of object classes are car, person, employee, etc. Properties are what humans use to distinguish or describe objects classes. Examples of properties are color, model, sex, age, etc. And representation is a set of valid value for a data element. For example, the data element representing annual household income may have the set of negative integers (with units of dollars) as a set of valid values.

2.2. Service Network Management Architecture of TINA TINA integrates information technology such as distributed processing, object oriented modeling and design with the typical telecommunications approach, given a framework for flexible design of advanced telecommunication system [lo]. TINA classifies the management architecture by the logical layers to manage the complex network management systems. The classified logical layers are NE(Network Element), NML(Network Management Layer), SML(Service Management Layer) and BML(Business Management Layer)[3]. Service management system of SML consists of access management, communication session management, customer information management, billing management and service session management. To support the interactions of many subsystems located in the TINA service management layer, it should improve flexibility and location transparency when service model is altered and guarantee reusability of software. Also, the service networking structure which plays a role of high level layer of network management must be networks plug-in structure in order to be easy to add, to change. Figure 1 shows that the integrated network management architecture for TINA.(see Figure 1.)

3. Object Management System: OMS 3.1. Design Principle of OMS The purpose of OMS is a separation of object oriented applications and middleware. It also stores/manages the managing objects in the metadataregistry. The OMS framework is devised to ensure data type and location transparencies without replying on code generation technique. It is our intent to provide data access transparency in OMS. In some sense, OMS can be regarded as a superset of data interface middleware. Application layer and OMS communicate using the object middleware CORBA and they provide an interface language IDL(1nterface Definition Language) that is defined regardless of client and server language, platform. This framework hybrid based software structure design reduces the complexity of the interface and decreases the cost of design and production by using IDL.

2.3. Metadata Registry based Approach Database management systems have been developed using various data models, data definition languages and dif-

176

Figure 3. Hybrid Structure of Common Interface and IDL

Figure 2. Architecture of Object Management System

Interfaces are managed by module such as OML. Every interface will manage a shared data, and so it has its needed data.

3.2.2 Object Management System (OMS)

3.2. Architecture of OMS

DM that is called from the application acquires the MO data from MDR through the DRM. DAM compares the data in MO and produces proper raw codes of RDB and interacts with stored data. Based on the value read from data storage, resulting values are transmitted to the application. To speed up interoperability, DRM is responsible for managing MOs previously retrieved from RDBs. Loose coupling between the physical database access unit (Data Access Manager) and the managed object manipulation units (DM and DRM) would bring interoperability to improvements. All of the three managers are implemented as parameterized classes. With the collaboration of the three managers, query processing is performed. DRM and DAM conceal their specific method of executing their roles from DM.

OMS is composed of three software managers: DM(Data Manager), DRM(metaData Registry Manager) and DAM(Data Access Manager). Figure 2 shows the OMS architecture.(see Figure 2 . ) The operations of three managers fundamentally rely on the data object generalization pattern [ 131[ 141. In OMS, DM is a facade interacting directly with managed objects. It provides managed objects with two query operations: Get operation for reading managed objects and Set operation for inserting, updating, and deleting managed objects. The input parameter of the two operations is the type of query object, which will be translated into SQL statement by DAM. DRM searches data needed in MDR(Metadata Registry) before accessing DAM or it simply supplies with easier access. This procedure reduces the traffic and increases efficiency. It is possible for DM to either belong to the same process with managed objects or be located in different sites. In latter case, ORB bridges between remote managed objects and DM.

3.2.3 Design and Implementation of OMS Using JAVA, We have implemented DM, DRM and DAM. For communication between DM and the managed object based on CORBA, Oribixweb 3.0 is used. For design of MDR, Oracle 8i is used. Figure 4 is an example of OMS System Viewer.(see Figure 4.) In check box, we can choose to use the remote managed object or the local managed object. When we choose the remote managed object, we communicate with DM by using ORB.

3.2.1 Design of Interface Structure In the distributed environment, to approach the data management, we will use an interface with CORBA. This interface structure is classified into custom, vertical, horizontal, hybrid structures according to the extension methods of the software structure design pattern and produce for a integrated interface. In Figure 3, the framework based hybrid structure was designed to overcome the limitations that the horizontal structure has by putting application objects that have common operations into horizontal interface structures and changing specific requests into vertical structure.(see Figure 3 . )

4. Prototype Implementation of MDR in TINA In this section, we have analyzed the functions of subsystems of TINA service management layer and defined managed objects and we have implemented MDR. Generally network management system is a dynamic system because user's demands have continuously changed and new

177

Table 1. Samples of Managed object Class in sub systems of SML Managed Object class

Description

CustomerInfo

Customer information management data object for managing customer. Management data object for searching VPN statue information. Management data object for managing billing basic data. Management data object for controlling PVC comDosition. Management data object for managing IP router's routing information.

VPNstatusInfo

BillData

Figure 4. OMS System Viewer equipments and its advanced technology are developed. To satisfy these requirements, MO must have a dynamic property. So we have applied OMS and MDR in TINA service management layer.

Routing Info

4.1. Extraction of Managed Objects and Data Elements Table 1 shows the samples of main managed objects. In order to represent metadata of subsystems, we have defined values of data elements refer to metadata to construct MDR.

4.2, Design of a metadata registry and data element The schema of the managed object class, which composes MDR, consists of the name of the managed object class, the schema of the managed object data element and the schema of the managed object procedure. The name of the managed object class distinguishes the managed object classes. The schema of managed object data element represents the data element in the managed object class. The data element does not store its own element's value but does store only the ID of data element. Figure 6 is the relation of the managed object classes.(see Figure 5.) Each class is referenced by each other. As a root class, CustomerInfo class has children classes as BillData class, PCG class, AccessNodeInfo class.

Figure 5. Relation of the managed object classes

So we have designed the architecture of Object Manage-

ment System. It performs the connection between the application layer and middleware such as ODBC and JDBC by using CORBA. It consists of three components such as Data Manager, Data Access Manager and metaData Registry Manager. Each function is implemented by using JAVA language. Also we have implemented Metadata Registry to manage dynamic data objects in distributed repositories, it is practical method to integrate heterogeneous and distributed repositories based on metadata. This method is rich enough to resolve most of the issues in integration of heterogeneous information resources. Previous information integration methods have proposed the solutions about only distributed and static information sources. So it is not suitable for dynamic environments such as TINA service management layer. To solve these

5. Conclusion The purposes of this paper are not only to design a architecture which support transparent interface between object oriented applications and distributed data repositories but also to suggest a methodology for integration of dynamic information resources in heterogeneous and distributed network environments.

178

[ 11J American National Standard for Information Technol-

problems, we have proposed the new methodology for not only static information sources but also dynamic resources. The proposed methodology is suitable for developing of the applications in TINA service management layer,

ogy, Metamodel for the management of sharable data, ANSI X3.285, Feb, 1999 [ 121 Information Technology-Specification and standardization of data element, ISO/IEC 1 1 179, part 1, FDIS,

6. References

1998 [I31 E. Gamma, R. Helm, R. Johnson, J. Vllissides, Desigri Patterns : Elements of Reusable Object-Oriented Software Addison Wesley, 1995

References [ 11 W. J. Barr, T. Boyd, and Y. Inoue. TINA Initiative IEEE Communications Magazine, Mar. 1993.

[ 141 Kyle Brown, Bruse G. Whitenack, Crossing Chasms : A Pattern Language for Object-RDBMS Integration White Paper, Knowledge System Corp., 1995:

[2] TINA-C Service Architecture Version 5.0 June 1997 [3] M. Keller, Richard Jensen, Shailesh Agarwal Persist Sofhvare: Bridging Object-Oriented Programming and Relational Database Proceeding of ACM SIGMOD International Conference on Management of Data, Washington DC, pp.523-528, 1993 [4] Gio Widerhold, Interoperation, Mediation, and Ontologies Proceedings International Symposium on Fifth Generation Computer System(FGCS94), Workshop on Heterogeneous Cooperative Knowledge-bases, Vol. W3, pp.33-48, ICOT, Tokyo, Japan, Dec. 1994

[ 5 ] Gio Widerhold, Value-added Mediation in Large-scale Information System Computer Science Department, Stanford University, 1996 [6] R. Neches, R.Fikes, T.Finin, T.R. Gruber, Enabling Technology for Knowledge Sharing AI Magazine, V01.12 No.3, pp.37-56, 1993 [7] J.C. Fanchitti, R.King, and O.Boucelma, A toolkit to Support Scalable Persistent Base Infrastructure Proc. of the Sixth International Workshop on Persistent Object System, Tarascon, France, Springer-Verlag LNCS, 1994 [8] LuisGravano, Hector Garcia-OMSina, and Anthony The EfSective of GLOSS for The Text Tomasic, Database Discovety Problem Proc. of The ACM SIGMOD Conference, ACM Sigmod Record, Vo1.23 No.2, pp. 126- 137, May 1994 [9] OMG, Common Object Service Specification OMG TC Document. 1995 [ 101 Roberto Minetti ,Flavio Piolini , TINA-Based Network

Resource Information Model for Next-Generation Mobile Systems The proceeding of the TINA'97-Global Convergence of Telecommunications and Distributed Object Computing, 1997, IEEE

179