Showing papers by "Djamel Sadok published in 2011"

Resource allocation for distributed cloud: concepts and research challenges

Abstract: In a cloud computing environment, dynamic resource allocation and reallocation are keys for accommodating unpredictable demands and, ultimately, contribute to investment return. This article discusses this process in the context of distributed clouds, which are seen as systems where application developers can selectively lease geographically distributed resources. This article highlights and categorizes the main challenges inherent to the resource allocation process particular to distributed clouds, offering a stepwise view of this process that covers the initial modeling phase through to the optimization phase.

CloudML: An Integrated Language for Resource, Service and Request Description for D-Clouds

Abstract: Distributed Clouds, or just D-Clouds, can be seen as a paradigm that is able to exploit the potential of sharing resources across geographic boundaries and provide latency-bound allocation of resources to third-party developers. The representation of D-Cloud resources is a challenge that involves the careful choice of characteristics that drive the mapping of requests on the substrate resources. Regarding these problems, this paper introduces the Cloud Modeling Language (CloudML), a vendor-neutral XML-based language intended to integrate the description of different cloud related aspects such as computational and network resources, services profiles, and developers' requests in an integrated way. Furthermore, the CloudML provides a way to describe geographical location aware services, seen particularly indispensable in D-Cloud scenarios.

Resource Allocation in Clouds: Concepts, Tools and Research Challenges

Abstract: Cloud computing is an attractive computing model since it allows for the provision of resources on-demand. Such a process of allocation and reallocation of resources is the key to accommodating unpredictable demands and improving the return on investment from the infrastructure supporting the Cloud. However, despite the recent growth of the Cloud Computing market, several problems with the process of resource allocation remain unaddressed. This short course introduces essential concepts and technologies regarding Cloud Computing and presents some research questions on the topic, focusing on the challenges and the state-of-the-art solutions in resource allocation.

A case for virtualization of content delivery networks

Abstract: Content Delivery Networks have gained a popular role among application service providers (ASPs) and infrastructural companies A CDN is an overlay network that gives more control of asset delivery by strategically placing servers closer to the end-user, reducing response time and network congestion Many strategies have been proposed to deal with aspects inherent to the CDN distribution model Though mostly very effective, a traditional CDN approach of statically positioned elements often fails to meet quality of experience (QoE) requirements when network conditions suddenly change In this paper, we introduce the idea of CDN virtualization The goal is to allow programmatically modification in CDN infrastructure designed for video distribution, adapting it to new operating conditions We developed a complete simulator focused on CDN overlay network characteristics where we implemented several approaches for each of the CDN elements Our results show a decrease of 20% in startup delay and network usage

Characterizing signature sets for testing DPI systems

Abstract: Deep Packet Inspection (DPI) is a crucial tool that enables more accurate network management and traffic profiling. Its high computational demands have been pushing networking researchers to study how to improve DPI technologies. However, in this quest for better performance, little effort has been devoted to making fair performance comparisons among DPIs. Even worse, most studies show performance gains by applying DPI techniques using specific, and sometimes small, signature sets. Consequently, one DPI engine may report a certain maximum throughput while another one may report a similar performance but may have used a significantly smaller signature set. This fact makes it clear that the research community needs a well-defined framework for testing new DPI systems. This paper proposes a new framework for characterizing signature sets for evaluating DPI systems and provides an in-depth analysis of signature sets from application, protocol, and intrusion detection systems.

Autonomic Cloud Computing: Giving Intelligence to Simpleton Nodes

Abstract: Autonomic Clouds emerge as a result of applying four self-management properties of Autonomic Computing (self configuration, self-healing, self-optimization, and self-protection) in Cloud environment. In this way, Autonomic Cloud Computing is seen as a Cloud with autonomy to take important decisions about resource management, such as the resource allocation for incoming requests, and the optimization decisions of resource utilization. The main goal of this paper is to make a brief discuss about issues of creating self-adaptive systems for Autonomic Clouds, focusing on infrastructure management level.

High-Performance Traffic Workload Architecture for Testing DPI Systems

Abstract: Traffic identification and classification are essential tasks performed by Internet Service Provider (ISPs) administrators. Deep Packet Inspection (DPI) is currently playing a key role in traffic identification and classification due to its increased expressive power. To allow fair comparison among different DPI techniques and systems, workload generators should have the following characteristics: (i) synthetic packets with meaningful payloads; (ii) TCP and UDP traffic generation; (iii) a configurable network traffic profile, and (iv) a high-speed sending rate. This paper proposes a workload generator framework which inherits all of the above characteristics. A performance evaluation shows that our flexible workload generator system achieves very high sending rates over a 10Gbps network, using a commodity Linux machine. Additionally, we have configured and tested our workload generator following a real application traffic profile. We then analyzed its results within a DPI system, proving its accuracy and efficiency.

Facilitating Service Creation via Partial Specification and Automated Composition

Abstract: Service composition is an important feature enabled by Service Oriented Computing but it remains mainly a manual process. Proposals for complete or partial automation of composition exist, the majority relying on artificial intelligence-based planning, automated proof techniques, or graph-based solutions. Although sound, these approaches present practical issues that prevent their use in production scenarios. This paper presents a composition tool that allows for partial service specification along with a composition algorithm based on the semantic matching of services inputs and outputs. Early performance numbers are also presented.

On traffic locality and QoE in hybrid CDN-P2P networks

Abstract: Hybrid CDN-P2P applications, such as P2P applications, tend to sometimes ignore traffic costs at ISPs and generate large amounts of undesirable cross-ISP traffic. As blocking the traffic does not seem to solve the problem, some simple cooperation between the neighboring peers will be beneficial. In this case, some biased neighbor selection helps peers connecting to others within the same Autonomous System, hence keeping communication local. We developed a detailed simulation model to evaluate the problem and discovered that using a biased neighborhood selection in a hybrid CDN-P2P content network can even enhance user's quality of experience (QoE) and fundamentally reduce the cross-ISP traffic even with the presence of a transit ISP making de-localization decisions.

Self-addressing for Autonomous Networking Systems

Abstract: Autoconfiguration is an important functionality pursued by research in the contexts of dynamic ad hoc and next generation of networks. Autoconfiguration solutions span across all architectural layers and range from network configuration to applications, and also implement cross-layer concepts. In networking, the addressing system plays a fundamental role as long as hosts must be uniquely identified. A proper identification is the base for other network operations, such as routing and security issues. Due to its importance, addressing is a challenging problem in dynamic and heterogeneous networks, where it becomes more complex and critical. This chapter presents a review and considerations for addressing autoconfiguration, focusing on the addressing procedure. Several self-addressing solutions for autonomous networks are surveyed, covering a wide range of possible methodologies. These solutions are also categorized according to the methodology they implement, their statefulness, and the way they deal with addresses duplication and/or conflicts. Special considerations regarding conformity to IPv6 are also presented. DOI: 10.4018/978-1-60960-611-4.ch007

Unleashing the power of policies for service-oriented computing

Abstract: Policies have the potential of playing a key role in Service Oriented Computing (SOC) providing many useful features for service creation, execution and management. However, so far the Policy-Based Management area has had a limited adoption and the result is that its advocated benefits still remain unproven in a broader sense. In this paper we show that the integration of policies with services using the Service Refinement Cycle can unleash their power of providing higher levels of adaptation to changing environment conditions and system requirements. We present different uses of policies for SOC and an example scenario.

AltoStratus: A Collaboration Network Focused on the New Research Challenges and Opportunities in Cloud Computing

Abstract: Cloud Computing is a new computing paradigm with the potential to radically change the way Internet applications and services are specified, developed, deployed, executed, managed, operated and evolved. Among the several benefits commonly associated with the adoption of cloud computing are: low initial investment, no need to maintain a physical infrastructure, reduction and greater control of operational costs, and high scalability. However, to fully achieve those benefits there are still a number of challenges to be addressed, especially regarding new solutions aimed at supporting application developers.This paper offers an overview, from the perspective of application development support, of the new research challenges and opportunities being created with the advent of cloud computing. To investigate those challenges is the main goal of the AltoStratus project, a recently created cloud computing research and collaboration network including researchers from eight Brazilian institutions located in three different regions of the country.