Catálogo de publicaciones - libros

This paper discusses a framework for a flexible, self-organized control plane for future mobile and ubiquitous networks. The current diversification of control planes requires a manual configuration of network interworking. The problem will increase in the future, with more dynamic topologies and integration of heterogeneous networks in a ubiquitous, reactive environment. In this paper we introduce the concept of network composition, a basic, scalable and dynamic network operation to achieve autonomic control plane interworking between Ambient Networks – our approach for next generation networks. We show the architectural components of a generic control plane and its flexible interfaces. With an example on seamless mobility we illustrate how composition can simplify and improve the interworking of future networks.

This paper presents some important directions in the use of ontology-based semantics in achieving the vision of Autonomic Communications. We examine the requirements of Autonomic Communication with a focus on the demanding needs of ubiquitous computing environments, with an emphasis on the requirements shared with Autonomic Computing. We observe that ontologies provide a strong mechanism for addressing the heterogeneity in user task requirements, managed resources, services and context. We then present two complimentary approaches that exploit ontology-based knowledge in support of autonomic communications: service-oriented models for policy engineering and dynamic semantic queries using content-based networks. The paper concludes with a discussion of the major research challenges such approaches raise.

In this paper, we present a feedback-based system for managing trust and detecting malicious behavior in autonomically behaving networks. Like other distributed trust management systems, nodes rate the interactions they have with other nodes and this information is stored in a distributed fashion.

Two crucial insights motivate our work. We recognize as separate entities the trust placed in a node, , and the trust placed in the recommendations made by a node, . We also introduce the concept of quality of a trust rating. Together, these two factors enhance the ability of each node to decide how much confidence it can place in a rating provided to it by a third party.

We implement our scheme on a structured P2P network, Pastry, though our results can be extended to generic autonomic communication systems. Experimental results considering different models for malicious behavior indicate the contexts in which the RQC scheme performs better than existing schemes.

Autonomic Communication is a new paradigm for dynamic network integration. An Autonomic Network crosses organizational boundaries and is provided by entities that see each other just as business partners. Policy-base network anagement already requires a paradigm shift in the access control mechanism (from identity-based access control to trust management and negotiation), but this is not enough for cross organizational autonomic communication. For many services no partner may guess a priori what credentials will be sent by clients and clients may not know a priori which credentials are required for completing a service requiring the orchestration of many different autonomic nodes.

We propose a logical framework and a Web-Service based implementation for reasoning about access control for Autonomic Communication. Our model is based on interaction and exchange of requests for supplying or declining missing credentials. We identify the formal reasoning services that characterise the problem and sketch their implementation.

The goal of this research is to create robust execution circuits for communication software which can distribute over a network and which continues to provide its service despite parts of the implementation being knocked out. Like packets that can be lost (which can be recovered by the appropriate protocols) we envisage an environment where parts of a protocol’s execution can be lost. The remaining implementation elements should continue to operate and be able to recover by themselves for restoring full services again. Based on a chemical execution model, we show a few initial examples of packet processing functions that are robust against the knock-out of any single instruction. These examples illustrate how the model can be applied to implement resilient communication protocols, to which we add regulatory signals that can be used to steer the protocols’ code basis.

Traditional network abstractions follow a layered model in which a sub-system interacts with other network components through very narrow interfaces. We content that this model is weak both in providing clear models of end-to-end properties and allowing adaptation to the more abstract properties of systems. We propose instead a graph-centric, contextual abstract model in which sub-systems can relate to other components at a wide range of semantic levels. We explore the implications such a model would have for network technology, applications and users, and identify some of the major research challenges it poses.

The conceptual architecture of autonomic communications requires a knowledge layer to facilitate effective, transparent and high level self-management capabilities. This pervasive knowledge plane can utilise the behaviour of autonomic communication regimes to monitor and intervene at many differing levels of network granularity. This paper discusses autonomic computing and autonomic communication, before outlining the role of behavioural knowledge in autonomic networks. Some research issues, in particular the concept of dynamic context as a method to acquire knowledge dynamically that will help to facilitate a successful realisation of the knowledge plane are explored and discussed.

Network users not only demand new and versatile application support by the networks but they themselves are becoming part of the network (network routers, caches, processors, etc) by contributing their resources to it and being engaged in ad hoc networking structures. As the large and diverse user population becomes more and more part of the networking infrastructure it is clear that networks will be dominated by a new type of network nodes which are much more nomadic, diverse and autonomic than in traditional networks, creating a fairly diverse – in size and characteristics – networking environment. For instance, low cost/high availability/convenience of wireless devices are expected to lead to the deployment of a plethora of wireless networks for diverse applications: from rescue missions to military communications, from collaborative computing and sensor networks to web browsing and e-mail exchange to real time voice and video communications. Each with different constraints and requirements. And, for each type of application there is also a high degree of variability in the networking context: from a low mobile network of a few nodes to a highly mobile network with thousands of nodes.

This high degree of variability in the networking environment calls for a new design paradigm where network elements (nodes) should be able to adapt to totally different scenarios, engaging in a different behavior depending on the situation. Thus, next generation networks should be able to learn their environment/context and adapt their behavior accordingly in order to achieve their goals. In this paper we introduce some key mechanisms required to enable broad adaptability. Although these mechanisms are general and common to a large variety of tasks/services (e.g. service discovery, location management, cooperative computing, clustering, etc.) we will discuss them in the context of the routing service, leveraging our past experience on the area. This will allow us to ground the discussion in concrete terms and the reader to better visualize the concepts.

The amount of information in the new emerging all-embracing pervasive environments will be enormous. Current Internet protocol conceived almost forty years ago, were never planned for these emerging pervasive environments. The communications requirements placed by these protocols on the low cost sensor and tag nodes are in direct contradiction to the fundamental goals if these nodes, being small, inexpensive and maintenance free. This situation needs therefore a radically different approach to communication in these systems, especially since pervasive and ubiquitous networks are expected to be the key drivers of the all encompassing Internet of the coming decades. The fundamental disparity between the need for extremely dispensable, low cost devices, such as sensors or tags, and increasing communications load per device due to the presence of billions of nodes, that is creating an unbridgeable paradox, is therefore an insurmountable obstacle on the way to adoption when conventional networking architectures are being considered. Biological systems provide insights into principles which can be adopted to completely redefine the basic concepts of control, structure, interaction and function of the emerging pervasive environments. The study of the rules of genetics and evolution combined with mobility, leads to the definition of service oriented communication systems which are autonomous, and autonomously self-adaptive. The objective of this article is to ascertain how this paradigm shift, which views a network only as a randomly self-organizing by-product of a collection of self-optimizing services, may become the enabler of the new world of omnipresent low cost pervasive environments of the future.

The subject and methodology of an emerging field related to physics, control theory and indormation theory are outlined. The paradigm of cybernetical physics as studying physical systems by cybernetical means is discussed. Examples of transformation laws describing excitability properties of dissipative and bistable systems are presented. A possibility of application to analysis and design of information transmission systems and complex networks is discussed.