Chunyan Fu

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.

A novel signaling system for multiparty sessions in peer-to-peer ad hoc networks

Multiparty sessions are the basis of a wealth of applications. Some examples are audio/video conferencing, distance learning and gaming. Peer-to-peer ad hoc networks are now emerging. They are useful in a wide range of application scenarios in personal, commercial, public and military environments. Very little is known today on how to handle multiparty sessions in these new networks. This paper proposes a novel signaling system for multiparty sessions in peer-to-peer ad hoc networks. The architecture relies on clustering. Requirements are derived and new principles are proposed. The principles are implemented as extensions to the session initiation protocol (SIP). Extending SIP enables easy interworking with conventional third generation telecommunication networks. The implementation is presented. We have also built a prototype, using JXTA, a middleware for peer-to-peer. The prototype is described with the measurements we have made.

Signaling for multimedia conferencing in 4G: the case of integrated 3G/MANETs

Fourth-generation wireless systems are composed of coexisting and cooperating legacy and new networks. Mobile ad hoc networks are examples of new networks. They have several attractive characteristics and are gaining more and more momentum. Their integration with legacy third-generation networks is now being contemplated. Multimedia conferencing is the basis of a wealth of applications, including video conferences, multiparty games, and distance learning. Signaling is the central nerve of multimedia conferencing. It establishes, modifies, and tears down multimedia conferencing applications. This article is devoted to the signaling aspects of multimedia conferencing in 4G and focuses on the specific case of integrated 3G/MANETs. It reviews the standard 3G architecture and the emerging architectures for MANETs. This review shows that none of them is suitable for integrated 3G/MANETs. We propose a new architecture based on application-level clusters and conference gateways. We have implemented a prototype using the session initiation protocol (SIP) technology

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.

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.

A Novel Architecture for Floor Control in the IP Multimedia Subsystem of 3G Networks

The IP Multimedia Subsystem (IMS) 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. It is the basis of a wide range of multiparty applications including audio/video conferencing, multiparty gaming and distance learning. Floor control is an important feature of multimedia conferencing. It manages the access to shared resources such as audio and video channels. This paper proposes a novel architecture for floor control in IMS. The architecture is an add-on to the IMS conferencing architecture. It includes a comprehensive set of server side and client side API that exposes the floor control capabilities to application developers. It enables the use of emerging industry standards such as SIP MSCML and JSR 309. Furthermore it proposes a novel interface (the SIP Floor Server Control Mark Up (SIP-FSCML) Language) as an alternative to Megaco/H.248 for controlling floor control servers. We successively introduce the overall architecture, the novel APIs, the communication interfaces (including SIP-FSCML) and the proof of concept prototype.

A Novel Lookup Service Enabler for Presence-Based Applications and Its Architecture in the 3GPP IP Multimedia Subsystem

This paper proposes a novel lookup service enabler for presence-based applications and its architecture in the 3GPP IP Multimedia Subsystem (IMS). The new service enabler makes possible the realization of a wide range of new (or enhanced) enduser applications. It allows end-users to discover groups of persons (or objects) that meet specific constraints (e.g. have specific interests or abilities, are available at a specific time at a specific location, and/or have specific affiliation(s)). The architecture relies on a novel abstract presence object (i.e. a nonuser presentity) that represents a group of entities that may belong to different domains. The current presence model and presence information data format (PIDF) are extended to support this object. A new entity (i.e. a lookup server) is introduced to enable the lookup service through a seamless aggregation of the results collected from the different presence servers deployed across the implicated IMS networks. A proof-of-concept prototype was built and is described in the paper.

A Peer to Peer Architecture for Enabling a Universal Presence Service

Presence service is used to publish and discover end-users’ context information. It is the basis of a wide range of end-user services. It is deployed using a wide range of technologies, which hampers interoperability. This paper proposes a peer to peer infrastructure for enabling a universal presence service, a service that will enable end-users with multiple presence accounts in domains with different technologies to publish and discover end-user context information through a single interface. Requirements are derived, an architecture is proposed and implementation aspects are discussed. The architecture is an overlay and the related procedures and protocols are introduced. New software architecture is proposed for the implementation and the related tool kits are identified.

Signaling for Conferencing in Integrated 3G/Mobile Ad Hoc Networks

Conferencing represents an important category of applications, which includes videoconferences and distance learning. To our knowledge, there is no signaling architecture for conferencing in integrated 3G/mobile ad hoc networks. However, there are architectures for conferencing in stand alone 3G and in stand alone mobile ad hoc networks. Unfortunately, none are suitable when the two networks are integrated. This paper proposes a novel signaling architecture for conferencing in integrated 3G/mobile ad hoc networks. This architecture is based on application-level clusters and conference gateways. The gateways mediate between the 3G and the mobile ad hoc networks. We have implemented a prototype using the Session Initiation Protocol as our technology.

A case study of a presence based end-user lookup service for the dynamic discovery of entities across technologies and domains

End-users may wish to interact with entities (e.g., groups of persons or physical objects) that need to be discovered dynamically. The entities may even reside in domains where different technologies are used. This article presents a case study on the design and implementation of a novel lookup service for the dynamic discovery of entities across technologies and domains. This novel service allows end users to dynamically discover entities that meet specific constraints (e.g., interests or abilities, availability at a specific time or location, and/or affiliation(s)). It is a powerful enabler that may be used as a pillar for a wide range of other end-user services. The proposed architecture relies on presence service and RESTful Web services. The related security aspects are studied. A proof-of-concept prototype is built and its performance is evaluated.