1 Introduction and Motivation

  Today, distributed systems based on the client/server paradigm have made their way into commercial IT infrastructures. The price of the flexibility gained is a more complex technical management of the computing environment. Efficient operation and administration requires an integrated management, in other words administration should be based on a single conceptual platform, a so-called management architecture. We need homogeneous management models for all distributed applications aligned with concepts that have been developed for network management and which now are increasingly used for managing end system resources.

This task has become even more complex through the recent introduction of different management architectures (see e.g. (Hegering et al., 1994)). On the one hand, there is the well-known OSI management architecture that is primarily used in the telecommunications area; on the other hand, many IETF working groups are trying to extend the scope of the Internet (SNMP) management architecture, i.e. apply it to the management of distributed applications. The recently launched Web-Based Enterprise Management (WBEM) Initiative will introduce another architecture (see e.g. (Hudis and Sinclair, 1996)). Additionally, CORBA (Siegel, 1996) becomes increasingly important for management applications. Whereas this architecture has not been developed specifically for management applications but to generally support communication and cooperation within distributed applications, it seems promising to use it for management purposes, too. Unfortunately, the current state of CORBA-based management of end systems and applications leads to an isolated management island. Therefore, bridging between the mentioned management architectures is an important research topic today. Necessary for this bridging are generic management models for resources that can be mapped onto every architecture forming an integrated conceptual framework. These models have to describe the characteristics of resources to be administered from a management point of view. Today, the object-oriented approach is the most commonly accepted paradigm in management: Hence, so-called managed object classes (MOCs) provide abstractions of real resources for management purposes. Management acts on resources by manipulating the managed objects. For that, we first of all have to derive appropriate MOCs for management of distributed applications. This is done, as described below, based on terms and concepts of the Reference Model for Open Distributed Processing (RM-ODP, ISO 10746) in order to ensure the applicability of the MOCs to a wide range of distributed applications.

Our overall goal is to make integrated management, especially of distributed applications, feasible in an environment consisting of different management architectures. The management models have to be applicable in ``CORBA-only'' environments as well as in ``classical'' management environments that rely on the OSI- and Internet management architectures: They should be ready for CORBA-based management but also take advantage of the functionality delivered by already existing management platforms.

The paper is organized as follows (see Figure 1):

  

Figure 1: Overview of the approach

In section 2, we describe our approach to the definition of management models, i.e. MOCs, for distributed applications that is based on the RM-ODP. These models should be applicable to a vast majority of applications and be widely independent of management transport mechanisms and specifics of management architectures. Section 3 then describes a methodology for developing an object model for distributed applications covering not only the generic, but also the application-specific aspects. The focus of the approach lies on the object model's practical applicability for implementing management agents. It makes use of the Object Modeling Technique (OMT) as a notation for the computational and the engineering viewpoint languages and permits a seamless transition from abstract object models to concrete implementations in CORBA. An example of this concept is also given in this section. Since today's management environments are heterogeneous through the use of different management architectures, section 4 deals with the issue of enabling cooperation between these architectures and describes our inter-domain management environment. We demonstrate how gaps between the management architectures can be bridged by the use of management gateways. Section 5 summarizes our approach and concludes the paper.