Systems that support mobile agents are increasingly being used on the global Internet. Security concerns dealing with the protection of the execution environment from malicious agents are extensively being tackled. We concentrate on the reverse problem, namely how a mobile agent can beprotectedfrom malicious behaviour of the execution environment, which is largely ignored. We will

The Internet is rapidly changing from a set of wires and switches that carry packets into a sophisticated infrastructure that delivers a set of complex value-added services to end users. Services can range from bit transport all the way up to distributed value-added services like video teleconferencing, data mining, and distributed interactive simulations. Before such services can be supported in a general and dynamic manner, we have to develop appropriate resource management mechanisms. These resource management mechanisms must make it possible to identify and allocate resources that meet service or application requirements, support both isolation and controlled dynamic sharing of resources across organizations sharing physical resources, and be customizable so services and applications can tailor resource usage to optimize their performance. The Darwin project

. ANISE (Architectural Notions In Service Engineering) can be used to describe a range of telecommunications services, including those from the Intelligent Network. The approach is supported by the ANGEN (ANISE Generator) language for combining features, the ANISE language for defining features, and the ANTEST (ANISE Test) language for defining validation scenarios. It is explained how all three are translated into LOTOS (Language of Temporal Ordering Specification), permitting any number of features to be validated in isolation or in combination. The toolset to permit this and the ANISE feature library are discussed. Typical results are presented from the automated analysis of telecommunications services. R ESUM E. ANISE (Architectural Notions In Service Engineering) est utilis e pour la description d'une gamme vari ee de services de t el ecommunication, incluant ceux du R eseau Intelligent. L'approche offre le langage ANGEN (ANISE Generator) pour la combinaison des services, le lang...

This paper presents a new paradigm for network computing over the Internet called universal personal computing, where mobile users can access computing resources, network services, and personalized computing environments anywhere using any available terminals. The user and system requirements are defined, and an agent-based protocol architectural required to manage different mobile objects, i.e., users and terminals, in this computing environment is presented. Modifications of connection setup procedures between user application programs to enable addressing based on a global user identity are considered. The use of personal agents to facilitate interworking and management functions is proposed. Index Terms---Internet, mobile computing, personal communications. I. INTRODUCTION T HE Internet is emerging as the major global network for data communications, providing the means to interconnect a large number of heterogeneous computer networks. A large group of applications such as e-mai...

A brief explanation is given of the language ANISE (Architectural Notions In Service Engineering) that can be used to describe generic services as well as telecommunications services. The ANISE approach embodies a feature calculus that can be used to structure and analyse services. A description is given of the Plain Old Telephone Service using ANISE. This is extended for a number of typical features drawn from the Intelligent Network. It is shown how the description of features permits static and dynamic analysis of interactions. A partial semantics is given for ANISE using LOTOS (Language of Temporal Ordering Specification). This allows feature descriptions to be translated into LOTOS and analysed formally. Keywords Feature Calculus, Feature Interaction, Formal Method, Intelligent Network Service, LOTOS (Language of Temporal Ordering Specification), Service Architecture, Service Feature, Telecommunications 1 Introduction 1.1 Modelling Services using ANISE An architectural ...

The deployment of advanced network services such as virtual reality games, distributed simulation, and video conferencing, will require sophisticated resource management support. The reason is that the quality of the delivered service will depend both on what resources are allocated to the user, and how these resources are managed at runtime. This problem is challenging because the definition of Quality of Service (QoS) is in general user specific, so hardwired resource management mechanisms will not be sufficient. To address the runtime resource management problem, we introduce the concept of a delegate, a code segment that applications or service providers inject into the network to assist in the management of the network resources that are allocated to them. This approach allows users to tailor runtime resource management to best meet their specific needs. Moreover, since delegates execute inside the network, they can easily collect information on changing network conditions, and ca...

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This paper identifies two paradigms that influence the design of telematics systems nowadays: the protocol-centred and the object-centred paradigm. Both paradigms have been introduced to cope with interoperability, each in their own way. The coexistence of these paradigms can have enormous impact on the design telematics systems. This paper identifies some combined uses of both paradigms and some fundamental research problems related to the coexistence of these paradigms. 1 Introduction Telecommunications and distributed computing have become strongly related research areas [7, 9]. Where telecommunications used to concentrate on data transport (carrier) networks and distributed computing on end-user applications, telecommunications services are now associated with interactive, multimedia network facilities offered to end-users and integrated in distributed applications. Moreover, the terms telecom services and telecom/distributed applications are often used interchangeably. Telecommu...

Initial implementations of Middleware based on standards such as CORBA have concentrated on host and language transparency issues in order to demonstrate interoperability. They have largely adopted a NoReplication approach and have frequently neglected performance-at-scale issues. This has lead to a continuing deployment of either non-scalable FullReplication approaches or ad-hoc messaging-based Middleware for applications such as Intelligent Networks, WWW applications and Collaborative Virtual Reality. These applications require millions of objects globally distributed across hundreds of hosts and demand a very high throughput of low-latency method invocations. Our main research aim is to be able to reason about the performance of such applications when using scalable Partial-Replication and Object-Oriented approaches to Middleware. Our approach is to use a simulator to explore potential design and implemention choices. Our current simulatordriven design, called "MinORB", has been fu...

This paper addresses a dilemma raised by recent advances in networking technology, which provide support both for a rich variety of qualities of service, and for applications that connect many endpoints. Together, these features encourage the development of complex multi-party applications that use a diverse set of data types. This raises a two-fold problem: how do applicationdesigners choose and specify the many quality of service parameters that drive the ultimate performance of their applications; and how does the network efficiently manage its resources to support such a rich application mix? Our approach to this problem is to allow applications to be built around value-added services that encapsulate a variety of simpler resources. This enables both the specification of quality of service (QoS) in terms meaningful to applications, and global optimization of resource allocation across multiple streams and data types. In this paper, we present a network architecture and a preliminar...