This paper proposes to enhance the modeling capabilities of DMTFs common information model (CIM). Currently CIM is used to represent a conceptual view of the IT environment, by modeling concepts related to elements to be managed. However, CIM object manager (CIMOM) implementations can utilize these models in no more capacity than as a passive database. We observe that a lot more management functionality could be incorporated into CIMOM middleware by enriching CIM so that it is able to represent process models in addition to data models. Using this representation CIMOM can be empowered to take on the role of an active decision-making entity, rather than just being a repository of management data. This enables embedding of powerful functionality in the middleware, which is currently custom-built by management applications instead. We demonstrate our approach by embedding an accounting process model into CIM, to realize an accounting system that can be customized for different scenarios.

The demand for quickly delivering new applications is increasingly becoming a business imperative today. Application development is often done in an ad hoc manner, without standard frameworks or libraries, thus resulting in poor reuse of software assets. Web services have received much interest in industry due to their potential in facilitating seamless business-to-business or enterprise application integration. A web services composition tool can help automate the process, from creating business process functionality, to developing executable workflows, to deploying them on an execution environment. However, we find that the main approaches taken thus far to standardize and compose web services are piecemeal and insufficient. The business world has adopted a (distributed) programming approach in which web service instances are described using WSDL, composed into flows with a language like BPEL and invoked with the SOAP protocol. Academia has propounded the AI approach of formally representing web service capabilities in ontologies, and reasoning about their composition using goal-oriented inferencing techniques from planning. We present the first integrated work in composing web services end to end from specification to deployment by synergistically combining the strengths of the above approaches. We describe a prototype service creation environment along with a use-case scenario, and demonstrate how it can significantly speed up the time-to-market for new services.

This paper proposes extensions to DMTF's CIM Metrics model and introduces a new CIM schema for representing metering and accounting information. Usage accounting is an essential component infrastructure. It is needed for purposes such as resource provisioning, capacity planning, auditing, and for charging the customers. Though some efforts are underway in this direction, currently there is no standard defined which allows metrics and usage accounting information to be specified in a way that is uniform across management applications. This paper attempts to achieve that by formalizing the concepts involved, through an information model that is independent of the actual metrics used. The proposed information model enriches the CIM Metrics schema with the notions of composite metrics and monitoring records. Further, new classes have been defined to formalize the representation of metering and accounting information. We also describe some applications of the proposed information model.

Web Services are emerging as the standard mechanism for making information and software available programmatically via the Internet, and as building blocks for applications. A composite web service may be built using multiple component web services. Once its specification has been developed, the composite service may be orchestrated either using a centralized engine or in a decentralized fashion. Decentralized orchestration brings performance benefits, and improves scalability and concurrency. Dynamic binding coupled with decentralized orchestration adds high availability and fault tolerance to the system. However in such systems, the coordination between components needs to be carefully designed to ensure correct execution of the composite and to limit the synchronization overheads. In this paper, we categorize different forms of concurrency and provide an algorithm to identify these forms in a composite service specification. We explore different mechanisms for transferring data between the components in the presence of different forms of concurrency. Then we experimentally evaluate the efficiency and scalability of each mechanism. We also analyze the coordination requirements of a decentralized orchestration in the presence of dynamic binding and fault propagation.

Abstract A mobile agent is an object which can autonomously migrate in a distributed system to perform tasks on behalf of its creator. Security issues in regard to the protection of host resources, as well as the agent themselves, raise significant obstacles in practical applications of the agent paradigm. This article describes the security architecture of Ajanta, a Java‐based system for mobile agent programming. This architecture provides mechanisms to protect server resources from malicious agents, agent data from tampering by malicious servers and communication channels during its travel, and protection of name service data and the global namespace. We present here a proxy based mechanism for secure access to server resources by agents. Using Java's class loader model and thread group mechanism, isolated execution domains are created for agents at a server. An agent can contain three kinds of protected objects: read‐only objects whose tampering can be detected, encrypted objects for specific servers, and a secure append‐only log of objects. A generic authentication protocol is used for all client–server interactions when protection is required. Using this mechanism, the security model of Ajanta enforces protection of namespaces, and secure execution of control primitives such as agent recall or abort. Ajanta also supports communication between agents using RMI, which can be controlled if required by the servers' security policies. Copyright © 2001 John Wiley & Sons, Ltd.

A mobile agent represents a computation that can autonomously migrate in a network to perform tasks on behalf of its creator. This paper describes the security architecture of Ajanta, a Java-based system for mobile agent programming. This architecture provides mechanisms to protect server resources from malicious agents, agent data from tampering by malicious servers, and to protect the system infrastructure itself. An agent can carry three kinds of protected data: read-only objects, objects visible only to specific servers, and a secure append-only list of objects. Agents' access to server resources is controlled using a proxy-based mechanism. A generic authentication protocol is used for all sensitive client-server interactions. Ajanta also supports communication between remote agents using RMI, which can be controlled by the servers' security policies.

The paper gives an overview of Ajanta, a Java based system for mobile agent programming. We outline the Ajanta architecture, and discuss the basic elements that comprise an agent based application. Ajanta's programming environment is defined in terms of a set of primitive operations for agent creation, dispatch, migration and remote control. Agents can access server resources using a proxy based access control mechanism. We describe a scheme for agent migration based on the composition of some basic migration patterns which incorporate exception handling mechanisms. Finally, we present two agent based distributed applications implemented using the Ajanta system. One is a middleware which supports file sharing over the Internet and the other is a distributed calendar manager.

Abstract The paper describes the approach taken for configuration management in the Nexus distributed operating system. Nexus uses kernel‐level support for monitoring the failure or termination status of distributed components of an application. Periodic user‐level messages are not required for status monitoring. Group and dependency relationships between such components can be defined by the programmer for the purpose of configuration monitoring and management. An object belonging to a distributed application can be monitored by its host kernel for system‐defined exception conditions. When any of these conditions arise, other objects are notified through signals or messages, as specified by the programmer.

This paper describes the approach taken for configuration management in the Nexus distributed operating system. Nexus uses kernel-level support for monitoring status of distributed components of an application. Periodic user-level messages are no longer required for status monitoring. Group and dependency relationships between such components can be defined by the programmer for the purpose of configuration monitoring and management. An object belonging to a distributed application can be monitored by its host kernel for some system-defined exception conditions. When any of these conditions arise, other objects are notified through signals or messages, as specified by the programmer.>