Modelling & Improving Flow Establishment in RSVP

RSVP has developed as a key component for the evolving Internet, and in particular for the Integrated Services Architecture. Therefore, RSVP performance is crucially important; yet this has been little studied up till now. In this paper, we target one of the most important aspects of RSVP: its ability to establish flows. We first identify the factors influencing the performance of the protocol by modelling the establishment mechanism. Then, we propose a Fast Establishment Mechanism (FEM) aimed at speeding up the set-up procedure in RSVP. We analyse FEM by means of simulation, and show that it offers improvements to the performance of RSVP over a range of likely circumstances

The Cloud Services Innovation Platform-Enabling Service-Based Environmental Modelling Using Infrastructure-As-A-Service Cloud Computing

Service oriented architectures allow modelling engines to be hosted over the Internet abstracting physical hardware configuration and software deployments from model users. Many existing environmental models are deployed as desktop applications running on user\u27s personal computers (PCs). Migration to service - based modelling centralizes the modelling functions to service hosts on the Internet . Users no longer require high-end PCs to run models and model updates encapsulating science advances can be disseminated more rapidly by hosting the modelling functions centrally via an Internet host instead of requiring software updates to user\u27s PCs . In this paper we present the Cloud Services Innovation Platform (CSIP), an Infrastructure -as -a -Service cloud application architecture , used to prototype development of distributed and scalable environmental modelling services. CSIP aims to provide modelling as a service to support both interactive (synchronous) and batch (asynchronous) modelling. CSIP enables c loud-based computing resources to be harnessed for both new and existing environmental models supporting the disaggregation of work into subtasks which execute in parallel using a scalable number of virtual machines. This paper presents CSIP \u27s implementation using the RUSLE2 model as a prototype model. RUSLE2 model service benchmarks are presented to demonstrate performance gains from using cloud resources. We also provide benchmarks for virtualization overhead observed using popular virtual machine hypervisors and demonstrate how application profile characteristics significantly impact performance when virtualized

Performance modelling of a multiple threshold RED mechanism for bursty and correlated Internet traffic with MMPP arrival process

Access to the large web content hosted all over the world by users of the Internet engage many hosts, routers/switches and faster links. They challenge the internet backbone to operate at its capacity to assure e±cient content access. This may result in congestion and raises concerns over various Quality of Service (QoS) issues like high delays, high packet loss and low throughput of the system for various Internet applications. Thus, there is a need to develop effective congestion control mechanisms in order to meet various Quality of Service (QoS) related performance parameters. In this paper, our emphasis is on the Active Queue Management (AQM) mechanisms, particularly Random Early Detection (RED). We propose a threshold based novel analytical model based on standard RED mechanism. Various numerical examples are presented for Internet traffic scenarios containing both the burstiness and correlation properties of the network traffic

Optimal Content Downloading in Vehicular Networks

We consider a system where users aboard communication-enabled vehicles are interested in downloading different contents from Internet-based servers. This scenario captures many of the infotainment services that vehicular communication is envisioned to enable, including news reporting, navigation maps and software updating, or multimedia file downloading. In this paper, we outline the performance limits of such a vehicular content downloading system by modelling the downloading process as an optimization problem, and maximizing the overall system throughput. Our approach allows us to investigate the impact of different factors, such as the roadside infrastructure deployment, the vehicle-to-vehicle relaying, and the penetration rate of the communication technology, even in presence of large instances of the problem. Results highlight the existence of two operational regimes at different penetration rates and the importance of an efficient, yet 2-hop constrained, vehicle-to-vehicle relaying

Exchange Communication Point Modeling in the context of the Enterprise Architecture

It is important to understand the performance and operation of an Internet Exchange Point to improve the management, and to reduce the cost associated with implementation and the information shared. Enterprise Architecture supports the design of systems, according to the business domain processes, network infrastructure and all the different applications running. Existing Enterprise Architecture modelling languages only provide a general concept of a network and do not represent specific information such as the protocols used, the internet protocols or the network addresses used for sharing information. This paper proposes a set of new concepts and attributes to the technology layer of reference language (ArchiMate) to enhance the representation and management of the network infrastructure. The ArchiMate language extensions are then used in modelling two Case Studies of Internet Exchange Point implementation in the Portuguese Public Administration. It was possible to compute which services will have impact in case of failure

Assessing the drivers of virtual knowledge management impact in European Firm’s performance : an exploratory analysis

E-Business is a phenomenon that has progressed over the past decades at record speed, with considerable promise and hype. It has been embraced with varying degrees of enthusiasm and impact by both large firms and Small and Medium Enterprises (SME). Parallel with its development, E-Business has attracted research interests, seen in a plethora of new modules, programmes, models and tools. Knowledge Management (KM) is one tool that seams to gain a more relevant role, especially as managing knowledge has become increasingly important to all companies. Appropriate KM practices within organisations can be seen as one of the prerequisites to the enhancement of continuous performance improvement in the interne-based context. Thus, our aim is to develop a conceptual framework related to KM practices in a virtual context and to identify the nature of the relationship existing in those knowledge-driven elements and performance achievements. This paper aims to bridge the gap between the KM and e-business performance-related literatures from the viewpoint of European firms by establishing a model tested in European companies. For this purpose, we used a structural equation modelling analysis. The results show that KM has a positive impact on the maximization of e-business performance and that some elements individually have a positive influence on e-business performance. As limitations of the study, we consider the need for more research into this field and the inclusion of news elements such as technological readiness and management support to KM initiatives. The present study advances knowledge on the nature of the relative importance of different components of Internet-based KM as drivers of e-business performance and reinforces its importance as an integrated e-business tool.info:eu-repo/semantics/publishedVersio

A critical look at power law modelling of the Internet

This paper takes a critical look at the usefulness of power law models of the Internet. The twin focuses of the paper are Internet traffic and topology generation. The aim of the paper is twofold. Firstly it summarises the state of the art in power law modelling particularly giving attention to existing open research questions. Secondly it provides insight into the failings of such models and where progress needs to be made for power law research to feed through to actual improvements in network performance.Comment: To appear Computer Communication