Fatna Belqasmi

RESTful web services for service provisioning in next-generation networks: a survey

Next-generation networks, as envisioned by ITU-T, are packet-based networks, capable of provisioning consistent and ubiquitous services to end users independent of the network, access technology, and devices used. RESTful web services are now being contemplated as a technology for service provisioning in NGNs. They are emerging as an alternative, which may be more adequate than SOAP-based web services in some cases. SOAP-based web services are modular applications that can be discovered and invoked over a network. RESTful web services, on the other hand, are defined as a network architectural style for distributed hypermedia systems. This article presents a survey on RESTful web services for service provisioning in NGNs. It introduces the concept of RESTful web services and reviews the state of the art of RESTful-based service provisioning in NGNs. It also provides an evaluation of the overall suitability of RESTful web services for service provisioning in NGNs, and discusses research directions. RESTful web services do show significant potential for service provisioning in NGNs. However, open issues such as publication/discovery and mechanisms for the development of complex session-based services need to be solved before its full potential can be realized.

Wireless sensor network virtualization: early architecture and research perspectives

WSNs have become pervasive and are used in many applications and services. Usually, deployments of WSNs are task-oriented and domain-specific, thereby precluding reuse when other applications and services are contemplated. This inevitably leads to the proliferation of redundant WSN deployments. Virtualization is a technology that can aid in tackling this issue, as it enables the sharing of resources/infrastructure by multiple independent entities. In this article we critically review the state of the art and propose a novel architecture for WSN virtualization. The proposed architecture has four layers (physical layer, virtual sensor layer, virtual sensor access layer, and overlay layer) and relies on a constrained application protocol. We illustrate its potential by using it in a scenario where a single WSN is shared by multiple applications, one of which is a fire monitoring application. We present the proof-of-concept prototype we have built along with the performance measurements, and discuss future research directions.

A multi-layer architecture for wireless sensor network virtualization

Wireless sensor networks (WSNs) have become pervasive and are used for a plethora of applications and services. They are usually deployed with specific applications and services; thereby precluding their re-use when other applications and services are contemplated. This can inevitably lead to the proliferation of redundant WSN deployments. Virtualization is a technology that can aid in tackling this issue. It enables the sharing of resources/infrastructures by multiple independent entities. This position paper proposes a novel multi-layer architecture for WSN virtualization and identifies the research challenges. Related work is also discussed. We illustrate the potential of the architecture by applying it to a scenario in which WSNs are shared for fire monitoring.

RESTful web services for bridging presence service across technologies and domains: an early feasibility prototype

A presence service enables the discovery and retrieval of, and subscription to changes in, an end user¿s context information. RESTful web services are now emerging as a lighter alternative to the so-called Big Web services. This article presents an early feasibility prototype of a RESTful web-services-based architecture. The architecture enables the discovery and retrieval of and subscription to changes in context information, independent of the technologies used in the end users¿ domains. Concretely, it enables end users with multiple presence accounts (e.g., MSN, Yahoo, Gmail) to publish context information related to the account(s) they are using at any given time. It also enables other end users or applications to retrieve this information by subscribing to any of the multiple accounts of the publisher. The project has demonstrated that RESTful web services are quite suitable for bridging services across technologies and domains. It has also demonstrated that a RESTful web services approach has several advantages over a traditional web services (also known as Big Web services) approach. However, more functionality needs to be added to the prototype before market introduction is contemplated. The lessons learned are discussed and the missing functionalities are identified.

SOAP-Based vs. RESTful Web Services: A Case Study for Multimedia Conferencing

RESTful Web services are now emerging as an alternative to SOAP-based Web services and might be a more suitable choice in some cases. A comparison of two Web programming interfaces - the standard Parlay-X multimedia SOAP-based Web service and a RESTful Web service that offers the same functionalities - for developing multimedia conferencing applications shows that the RESTful Web interface offers better performance.

Ambient network composition

Ambient networks, a product of a European union sixth framework project, is a novel networking paradigm for beyond 3G. It aims at the ubiquitous provisioning of existing and new services over any access technology and any type of network. Network composition is a core feature of ambient networks. It enables on-demand and transparent cooperation between heterogeneous networks, with little or no pre-configuration or off-line agreement. This article provides an overview of ambient network architecture and discusses composition concepts and techniques. The key concept is the composition degree. It is the level of cooperation between the composing networks. It ranges from network interworking, where each composing network keeps control of its resources, to network integration, where all of the composing networks merge into a single network. Network composition is a phased process. The techniques include the mechanisms that enable the interactions between the composing networks during each phase of the process. These mechanisms rely on general ambient network signaling, a signaling system based on the IETF next step in signaling framework. We introduce the ambient network architecture, review the composition degrees, present the composition techniques, and discuss how ambient network composition has been validated.

Design and implementation of advanced multimedia conferencing applications in the 3GPP IP multimedia subsystem

The IP multimedia subsystem is a key component of 3G networks. It enables the seamless provision of multimedia services to end users. Multimedia conferencing is an important category of multimedia services in IMS, serving as the basis for a wide range of applications including audio/video conferencing, multiparty gaming and distance learning. Floor control is an advanced feature of multimedia conferencing which manages the access to shared resources such as audio and video channels. This article extends the 3GPP architecture to include the design and implementation of advanced multimedia conferencing applications. It separates the floor control server and the media resource function processor, and it also opens up advanced conferencing capabilities. A SIP-based floor server control markup language and a multi-level abstraction API are proposed. The extensions are illustrated by a case study based on the design and implementation of a multiparty multimedia game. An important finding of this article is that tools and technologies for the design and implementation of multimedia conferencing applications in IMS are relatively immature. We therefore caution designers and implementers that they may need to develop additional tools and technologies to complete their projects, just as we did in the work presented in this article.

An infrastructure for robotic applications as cloud computing services

Robotic applications are becoming ubiquitous. They are widely used in several areas (e.g., healthcare, disaster management, and manufacturing). However, their provisioning still faces several challenges such as cost and resource usage efficiency. Cloud computing is an emerging paradigm that may aid in tackling these challenges. It has three main facets: Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS). This paper focuses on the IaaS aspects of robotic applications as cloud computing services. It proposes an architecture that enables cost efficiency through virtualization and dynamic task delegation to robots, including robots that might belong to other clouds. Overlays and RESTful Web services are used as cornerstones. A prototype is built using LEGO Mindstorms NXT as the robotic platform, and JXTA as the overlay middleware. Related work is reviewed, the functional entities and interfaces of the architecture are described, and the prototype architecture is presented along with the implemented scenario.

A Negotiation Framework for the Composition of Registries in Ambient Networks

Ambient Networks (AN) is a new networking concept for beyond 3G. Network composition is a core concept of AN. It provides dynamic cooperation between heterogeneous networks. Each ambient network can host several registries. When the networks compose, the registries also have to compose. This composition is based on a composition agreement that must be negotiated between the different parties involved. This paper presents a framework for dynamic negotiation of an agreement for the composition of registries. It presents the framework principles and a template for the composition agreement proposals, and describes the main steps of the negotiation. It also describes the negotiation protocol (i.e. entities, messages and state diagrams). We have validated our protocol using SPIN, a software tool for simulating and validating distributed systems behavior. The process and the results are discussed.

An Architecture for Composing Registries when Ambient Networks Compose

Ambient networks refer to a new networking concept for beyond 3G. They use automatic network composition to enable dynamic and instantaneous inter- working between heterogeneous networks on demand. Ambient networks can host several registries (e.g. management information bases, context information bases). When they autonomously compose, the hosted registries have to follow suit and compose. This paper focuses on the issues related to the autonomous composition of registries when ambient networks compose. We identify a set of requirements and propose a general architecture for autonomic composition. We also discuss cursorily information discovery after composition.