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Dive into the research topics where Stuart Clayman is active.

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Featured researches published by Stuart Clayman.


IEEE Computer | 2011

Reservoir - When One Cloud Is Not Enough

Benny Rochwerger; David Breitgand; Amir Epstein; David Hadas; Irit Loy; Kenneth Nagin; Johan Tordsson; Carmelo Ragusa; Massimo Villari; Stuart Clayman; Eliezer Levy; Alessandro Maraschini; Philippe Massonet; Henar Muñoz; Giovanni Tofetti

As cloud computing becomes more predominant, the problem of scalability has become critical for cloud computing providers. The cloud paradigm is attractive because it offers a dramatic reduction in capital and operation expenses for consumers.


network operations and management symposium | 2014

The dynamic placement of virtual network functions

Stuart Clayman; Elisa Maini; Alex Galis; Antonio Manzalini; Nicola Mazzocca

This paper addresses the problem of managing highly dynamic network and service environments, where virtual nodes and virtual links are created and destroyed depending on traffic volumes, service requests, or high-level goals such as reduction in energy consumption. This problem will be one of the main technical challenges to be faced in the evolution towards Future Networks (FN). Emerging paradigms such as Software Defined Networks (SDN) and Network Function Virtualization (NfV) are concrete steps towards infrastructures where network functions and services will be executed as applications in ensembles of virtual machines (VMs) hosted in pervasive standard hardware resources located across a network. The paper argues that in order to manage these virtual infrastructures there is a need to introduce high-level systems orchestration. The paper describes an architecture based on an orchestrater that ensures the automatic placement of the virtual nodes and the allocation of network services on them, supported by a monitoring system that collects and reports on the behaviour of the resources. The orchestrater manages the creation and removal of the virtual nodes, as well as configuring, monitoring, running and stopping software on them. As a proof of these concepts, a distributed orchestrater prototype has been designed, implemented and tested with the results of different placement algorithms presented.


network operations and management symposium | 2010

Monitoring virtual networks with Lattice

Stuart Clayman; Alex Galis; Lefteris Mamatas

The use of the Lattice monitoring framework as a fundamental part of a overlay management system for virtual networks is presented. Lattice has been specially designed for monitoring resources and services in virtualized environments, including virtual networks. Monitoring of virtualized resources and services has many criteria which are not relevant for monitoring systems that are used for traditional fixed resources. We present the main aspects of the framework together with details of measurement transmission and meta-data encoding. Finally, the use of the Lattice framework for monitoring virtual machines executing under hypervisor control is presented.


IEEE Transactions on Network and Service Management | 2015

Adaptive Resource Management and Control in Software Defined Networks

Daphne Tuncer; Marinos Charalambides; Stuart Clayman; George Pavlou

The heterogeneous nature of the applications, technologies and equipment that todays networks have to support has made the management of such infrastructures a complex task. The Software-Defined Networking (SDN) paradigm has emerged as a promising solution to reduce this complexity through the creation of a unified control plane independent of specific vendor equipment. However, designing a SDN-based solution for network resource management raises several challenges as it should exhibit flexibility, scalability and adaptability. In this paper, we present a new SDN-based management and control framework for fixed backbone networks, which provides support for both static and dynamic resource management applications. The framework consists of three layers which interact with each other through a set of interfaces. We develop a placement algorithm to determine the allocation of managers and controllers in the proposed distributed management and control layer. We then show how this layer can satisfy the requirements of two specific applications for adaptive load-balancing and energy management purposes.


the internet of things | 2011

INOX: a managed service platform for inter-connected smart objects

Stuart Clayman; Alex Galis

In this paper we present a service management platform and an architecture which integrates the features of IoT with the management features of modern autonomic network management, and many service features from the world of Services. We present an architecture for INOX, a robust and adaptable Service Platform for the Internet of Things and Inter-Connected Smart Objects. The platform integrates many of the ideas from Autonomic Network Management and Services and provides the functionality which allows for better use of the sensors, things and the smart objects through enhanced application development, more flexible service deployment, virtualized elements, and better service management. This paper presents the current status of our work on a reference framework for the management and integration of smart objects and virtual networks into such a service platform.


IEEE Transactions on Computers | 2013

On the Selection of Management/Monitoring Nodes in Highly Dynamic Networks

Richard G. Clegg; Stuart Clayman; George Pavlou; Lefteris Mamatas; Alex Galis

This paper addresses the problem of provisioning management/monitoring nodes within highly dynamic network environments, particularly virtual networks. In a network, where nodes and links may be spontaneously created and destroyed (perhaps rapidly) there is a need for stable and responsive management and monitoring, which does not create a large load (in terms of traffic or processing) for the system. A subset of nodes has to be chosen for management/monitoring, each of which will manage a subset of the nodes in the network. A new, simple, and locally optimal greedy algorithm called Pressure is provided for choice of node position to minimize traffic. This algorithm is combined with a system for predicting the lifespan of nodes, and a tunable parameter is also given so that a system operator could express a preference for elected nodes to be chosen to reduce traffic, to be stable,” or some compromise between these positions. The combined algorithm called PressureTime is lightweight and could be run in a distributed manner. The resulting algorithms are tested both in simulation and in a testbed environment of virtual routers. They perform well, both at reducing traffic and at choosing long lifespan nodes.


2013 IEEE SDN for Future Networks and Services (SDN4FNS) | 2013

Softwarization of Future Networks and Services -Programmable Enabled Networks as Next Generation Software Defined Networks

Alex Galis; Stuart Clayman; Lefteris Mamatas; Javier Rubio Loyola; Antonio Manzalini; Slawomir Kuklinski; Joan Serrat; Theodore B. Zahariadis

The Software Defined Networks (SDNs) and Network Functions Virtualisation (NFVs), as recent separate research and development trends have the roots in programmable / active network technologies and standards developed a decade ago. In particular, they are associated with the decoupling of forwarding from control and hardware from networking software, using open interfaces to connectivity resources. The next phase of R&D would involve novel integration and use of all connectivity, storage and processing resources under new management interacting with control systems for provisioning of on-demand networking and services with continuous update of features. This brings into focus a relatively new and key topics for the next decade: what and how to create the conditions for effective and continuous updating and changing the networking functions without reinventing each time architectural aspects and related components (e.g. Softwarization of Future Networks and Services or Programmable Enabled Networks). This paper presents motivation, architecture and the key challenges in realising such programmable enabled networks as the next generation Software Defined Networks focusing on its management plane.


international conference on communications | 2009

Management and service-aware networking architectures (MANA) for future Internet — Position paper: System functions, capabilities and requirements

Alex Galis; Henrik Abramowicz; Marcus Brunner; Danny Raz; Prosper Chemouil; Joe Butler; Costas Polychronopoulos; Stuart Clayman; Hermann de Meer; Thierry Coupaye; Aiko Pras; Krishan K. Sabnani; Philippe Massonet; Syed Naqvi

Future Internet (FI) research and development threads have recently been gaining momentum all over the world and as such the international race to create a new generation Internet is in full swing: GENI [16], Asia Future Internet [19], Future Internet Forum Korea [18], European Union Future Internet Assembly (FIA) [8]. This is a position paper identifying the research orientation with a time horizon of 10 years, together with the key challenges for the capabilities in the Management and Service-aware Networking Architectures (MANA) part of the Future Internet (FI) allowing for parallel and federated Internet(s).


global communications conference | 2010

Platforms and Software Systems for an Autonomic Internet

Javier Rubio-Loyola; Antonio Astorga; Joan Serrat; Wei Koong Chai; Lefteris Mamatas; Alex Galis; Stuart Clayman; A. Cheniour; Laurent Lefèvre; Olivier Mornard; Andreas Fischer; Alexandru Paler; H. de Meer

The current Internet does not enable easy introduction and deployment of new network technologies and services. This paper aims to progress the Future Internet (FI) by introduction of a service composition and execution environment that re-use existing components of access and core networks. This paper presents essential service-centric platforms and software systems that have been developed with the aim to create a flexible environment for an Autonomic Internet


Journal of Functional Programming | 1995

Lexical profiling: theory and practice

C Clack; Stuart Clayman; David Parrott

This paper addresses the issue of analysing the run-time behaviour of lazy, higher-order functional programs. We examine the difference between the way that functional programmers and functional language implementors view program behaviour. Existing profiling techniques are discussed and a new technique is proposed which produces results that are straightforward for programmers to assimilate. The new technique, which we call lexical profiling, collects information about the run-time behaviour of functional programs, and reports the results with respect to the original source code rather than simply listing the actions performed at run-time. Lexical profiling complements implementation-specific profiling and is important because it provides a view of program activity which is largely independent of the underlying evaluation mechanism. Using the lexical profiler, programmers may easily relate results back to the source program. We give a full implementation of the lexical profiling technique for a sequential, interpretive graph reduction engine, and extensions for compiled and parallel graph reduction are discussed.

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Alex Galis

University College London

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Clovis Chapman

University College London

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George Pavlou

University College London

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Joan Serrat

Polytechnic University of Catalonia

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Daphne Tuncer

University College London

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