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Systems Management: Reference Model

Systems Management: Reference Model
Copyright © 1997 The Open Group

Interoperability between OMG and XMP


The following sections discuss different architectural approaches for providing integration and interoperability between an OMG based system management reference model implementation and an XMP based system management reference model implementation. There are two basic approaches to support this interoperation, including:

Parallel Frameworks
The managed Resources are encapsulated by an object from both the OMG based framework and the XMP based framework. Integration takes place "below" the object models.

Object Gateways
An object is defined in the OMG based framework which corresponds to or encapsulates one or more objects in the XMP based framework. This object implementation acts as a client or gateway to one or more XMP based objects, translating and forwarding object requests.

Although these approaches are expressed as mapping OMG object requests into XMP requests, the architectures can be symmetrical (XMP object agent programs can act as OMG clients making ORB compliant object requests; e.g., XMP based objects). In addition, these approaches, particularly that of Object Gateways, are suitable for implementing interoperability between XSM and legacy management systems.

The provision of services within the different models must also be addressed in order to achieve interoperability. The services summarised within the Reference Model identify the basic functionality that is required from those services. In order to have portability across the OMG and XMP environments, it is necessary to specify how the services relate to each other. To make portability work, the functionality and the interface to the services must be defined. To make interoperability work, where there are differences between the underlying services, a mapping between them is required.

Parallel Framework Interoperation

In this approach to interoperation between OMG based and XMP based versions of the XSM reference model, the managed Resource can be accessed either through the OMG framework or the XMP programming interfaces by making object requests on the Managed Object defined in each framework which encapsulates the same managed Resource state. Client programs would be written to use one framework; that is, the interoperation is through the Managed Object state itself. Each managed Resource would be described by both an IDL interface definition and an XOM class definition, and an object implementation provided.

Parallel Framework Interoperability shows the parallel framework architecture. Note that integration is achieved through the managed Resource itself; that is, it is likely that the OMG and XMP object implementations will access the same underlying data store to obtain and manage the Resource state, and will need to use a common consistency mechanism. A possible implementation in this environment is an agent program which exports both the OMG interface and the XMP interface; that is, a single object implementation. Another implementation would involve using a common data Manager which supported a multiple access consistency mechanism (such as a Relational DBMS).

Figure: Parallel Framework Interoperability

An event notification registry service is defined in the OMG framework to enable Management Tasks to register for and receive both OMG based events and XMP based notification event reports. The service would also act as a store and forward notification mechanism with appropriate notification grouping and filtering capabilities.

In practice, one would expect each management application to be implemented upon one framework that was most applicable; e.g., applications requiring a specific management application view might use the OMG based framework, and applications requiring a network management view might use the XMP based framework.

Object Gateways

In this approach to interoperation between OMG based and XMP based versions of the XSM reference model, special objects are used to encapsulate the object requests of one implementation into an object of the other implementation. OMG and XMP Object Interoperability shows how OMG based objects can be used to translate and forward object requests to XMP based objects. Each of these special objects is a server in the OMG framework to a management client entity (a Management Task) and a client in the XMP framework acting as a Manager. This object forwards requests and returns responses between the OMG Management Task and the XMP Managed Object using the XMP programming interfaces. The gateway object is also responsible for initialising the XMP Manager environment, setting up the buffers and session object.

Figure: OMG and XMP Object Interoperability

With a few conventions in defining the OMG based object interface in the IDL language, it would be possible to create an IDL interface that is isomorphic to the XOM class definition for the Managed Object. That is, the gateway object definition corresponds directly with the Managed Object interface definition in terms of public attributes, operations, and exceptions. The IDL defines the interface to the OMG based object, and the XOM class definition is used within the object implementation to forward the request and return the response. The translation from one interface implementation to the other is inherent in the gateway object's implementation. Such objects can use the OMG Naming service to translate Managed Object "names" to agent program Titles/Addresses, or use the XMP automatic location mechanism. They may also forward events from the corresponding XMP based object or objects.

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