Djamal Zeghlache

A Distributed Virtual Network Mapping Algorithm

Network visualization is a promising concept to diversify the future Internet architecture into separate virtual networks (VN) that can support simultaneously multiple network experiments, services and architectures over a shared substrate network. To take full advantage of this paradigm this paper addresses the challenge of assigning VNs to the underlying physical network in a distributed and efficient manner. A distributed algorithm responsible for load balancing and mapping virtual nodes and links to substrate nodes and links has been designed, implemented and evaluated. A VN mapping protocol is proposed to communicate and exchange messages between agent-based substrate nodes to achieve the mapping. Results of the implementation and a performance evaluation of the distributed VN mapping algorithm using a multi-agent approach are reported.

Virtual network provisioning across multiple substrate networks

This paper addresses the provisioning of virtual resources in future networks relying on the Infrastructure as a service principle. Exact and heuristics optimization algorithms for the provisioning of virtual networks involving multiple infrastructure providers are presented. The study assumes the emergence of new actors such as virtual network providers acting as brokers requesting virtual resources on behalf of users. Resource matching, splitting, embedding and binding steps required for virtual network provisioning are proposed and evaluated. Splitting of the virtual network provisioning request across multiple infrastructure providers is solved using both max-flow min-cut algorithms and linear programming techniques. Virtual network embedding is formulated and solved as a mixed integer program with the aim of decreasing embedding cost for infrastructure providers while increasing the acceptance ratio of requests. Performance of the splitting and embedding algorithms is reported.

Energy Efficient VM Scheduling for Cloud Data Centers: Exact Allocation and Migration Algorithms

This paper presents two exact algorithms for energy efficient scheduling of virtual machines (VMs) in cloud data centers. Modeling of energy aware allocation and consolidation to minimize overall energy consumption leads us to the combination of an optimal allocation algorithm with a consolidation algorithm relying on migration of VMs at service departures. The optimal allocation algorithm is solved as a bin packing problem with a minimum power consumption objective. It is compared with an energy aware best fit algorithm. The exact migration algorithm results from a linear and integer formulation of VM migration to adapt placement when resources are released. The proposed migration is general and goes beyond the current state of the art by minimizing both the number of migrations needed for consolidation and energy consumption in a single algorithm with a set of valid inequalities and conditions. Experimental results show the benefits of combining the allocation and migration algorithms and demonstrate their ability to achieve significant energy savings while maintaining feasible convergence times when compared with the best fit heuristic.

Adaptive virtual network provisioning

In the future, virtual networks will be allocated, maintained and managed much like clouds offering flexibility, extensibility and elasticity with resources acquired for a limited time and even on a lease basis. Adaptive provisioning is required to maintain virtual network topologies, comply with established contracts, expand initial allocations on demand, release resources no longer useful, optimize resource utilization and respond to anomalies, faults and evolving demands. In this paper, we elaborate on adaptive virtual resource provisioning to maintain virtual networks, allocated initially on demand, in response to a virtual network creation request. We propose a distributed fault-tolerant embedding algorithm, which relies on substrate node agents to cope with failures and severe performance degradation. This algorithm coupled with dynamic resource binding is integrated and evaluated within a medium-scale experimental infrastructure.

Review: A review on mobility management and vertical handover solutions over heterogeneous wireless networks

In the nowadays heterogeneous wireless environment, a plethora of access networks have to be inter-connected in an optimal manner to meet the always best connected paradigm. This paper highlights some of the main technical challenges in heterogeneous wireless networks underlying seamless vertical handover making as a fundamental feature to all future networking endeavors. It provides a survey on the vertical mobility management process and mainly focuses on decision making mechanisms. After presenting the related standards, the main vertical handover approaches in the literature are analyzed and compared. The paper also points out the importance of multihoming in a such heterogeneous environment and provides an overview of the most known supporting mobility protocols. Finally, the main research trends and challenges are discussed.

Network-based virtual personal overlay networks using programmable virtual routers

This article explores the use and adaptation of well established VPN technologies to dynamically network at run time devices and services in personal networks. Virtual personal overlay networks are envisaged as an extension of the basic VPN concept to network PN nodes in a secure manner. User managed and provider provisioned-based overlays are analyzed in terms of scalability, management complexity, and security to select the most appropriate VPON deployment and management framework. The dynamic nature of PNs calls for highly flexible self-configuring and self-adaptive VPON architectures. Programmable edge routers and dynamic tunneling mechanisms can be combined to meet the requirements set by PNs. The virtual router model is used in the provider edge to ease the dynamic deployment and management of VPONs. Results of an implementation and a performance evaluation of the VR concept based on open software routers are reported.

Cloud Service Delivery across Multiple Cloud Platforms

The paper presents work-in-progress on the cloud service provisioning across multiple cloud providers. The work assumes the emergence of Cloud Brokers between customers and cloud providers. The brokers split user requests and ensure provisioning from multiple providers. An exact splitting algorithm is developed to efficiently split the cloud requests among the multiple cloud platforms with the aim of decreasing the cost for customers. This splitting is formulated as a Mixed Integer Program and this is combined with Open Flow and NOX technologies that achieve flow based inter-cloud networking. A new controller module is developed and integrated in NOX to configure the Open Flow switches for inter-cloud path establishments.

Trust management system design for the Internet of Things: A context-aware and multi-service approach

This work proposes a new trust management system (TMS) for the Internet of Things (IoT). The wide majority of these systems are today bound to the assessment of trustworthiness with respect to a single function. As such, they cannot use past experiences related to other functions. Even those that support multiple functions hide this heterogeneity by regrouping all past experiences into a single metric. These restrictions are detrimental to the adaptation of TMSs to todays emerging M2M and IoT architectures, which are characterized with heterogeneity in nodes, capabilities and services. To overcome these limitations, we design a context-aware and multi-service trust management system fitting the new requirements of the IoT. Simulation results show the good performance of the proposed system and especially highlight its ability to deter a class of common attacks designed to target trust management systems.

Virtual Resource Description and Clustering for Virtual Network Discovery

This paper explores description and clustering techniques for virtual networks provisioning from shared physical resources. The contribution consists of a virtual resource description schema to specify properties and relations between virtual resources and a conceptual clustering technique to facilitate matching and discovery. Conceptual clustering provides a hierarchical classification of virtual resources and concept descriptions for clusters. Performance results benefits of conceptual clustering for resource matching are reported.

A Distributed and Autonomic Virtual Network Mapping Framework

This paper addresses the challenge of assigning virtual networks, through network virtualisation, to the underlying physical network in a distributed and efficient manner. The paper reports on an implementation and evaluation of a distributed and autonomic framework with algorithms responsible for mapping virtual nodes and links to the physical resources. A virtual network (VN) mapping protocol is proposed for exchange of messages between autonomic substrate nodes. Results of the implementation and a performance evaluation of the distributed and autonomic VN mapping using a multi-agent approach are provided.