Salvatore Loreto

Real-Time Communications in the Web: Issues, Achievements, and Ongoing Standardization Efforts

Web Real-Time Communication (WebRTC) is an upcoming standard that aims to enable real-time communication among Web browsers in a peer-to-peer fashion. The IETF RTCWeb and W3C WebRTC working groups are jointly defining both the APIs and the underlying communication protocols for setting up and managing a reliable communication channel between any pair of next-generation Web browsers.

Service broker architecture: Location business case and mashups

In recent years, costly and slow integration has created an unnecessary gap between the telephone companies (or telco) and IT worlds. However, collaboration between Internet and telecom standards is essential for future development. The service broker concept has been developed to fill this gap. Indeed, the service broker provides a flexible layer in the telecom architecture to bridge these two worlds. Such a concept is essential to coordinate the diverse future services and provide mashup opportunities through a single point of entry. In this article we present the concept and an actual implementation of a specific service broker: a location service broker. Moreover, we also present a sample mashup called MoPoint that we implemented to better demonstrate the functionality of the location service broker. MoPoint is a Web site where the user can see the current location of his or her mobile displayed on a map along with local weather and advertisements.

A distributed IMS enabled conferencing architecture on top of a standard centralized conferencing framework [IP Multimedia Systems (IMS) Infrastructure and Services]

In this article we present an actual implementation of a distributed conferencing framework compliant with the IP multimedia core network subsystem specification. The architecture we describe has been realized by exploiting existing achievements in the field of conferencing. More precisely, starting from the IETF centralized conferencing (XCON) framework and based on an open source XCON implementation provided by our research group, we devised a distributed conferencing solution that was implemented as an overlay network of centralized conferencing clouds. The articles goal is to provide the reader with useful information about our experience with IMS implementation and deployment. We first describe our architecture from a high level design perspective and subsequently analyze it in detail by highlighting the most notable implementation choices

Using RELOAD and CoAP for wide area sensor and actuator networking

In this article, we propose a new architecture for wide area sensor and actuator networking. The architecture is based on combining two protocols being standardized by the Internet Engineering Task Force, REsource LOcation And Discovery (RELOAD) and Constrained Application Protocol (CoAP). To integrate CoAP and RELOAD, we introduce a CoAP application usage for RELOAD. The architecture provides a decentralized peer-to-peer rendezvous service for CoAP nodes in Wireless Sensor Networks (WSNs). Our architecture also enables a peer-to-peer federation of geographically distributed WSNs. This is supported by proxy nodes that are part of the WSN but also connect to a RELOAD overlay network via cellular Internet access. Due to the use of RELOAD, the system does not need to rely on centralized services such as DNS service discovery (DNS-SD) or central resource directories to discover sensors and resources. Other features of the architecture include integration to web, self-organization, scalability, and robustness. We evaluate the proposed architecture through simulations and real-life measurements, and compare its performance to a traditional client/server architecture.

IMS service development API and testbed

The IP multimedia subsystem defined by the Third Generation Partnership Project is the architecture merging the Internet and telecom worlds. The IMS was designed to make it easy for third-party developers to make their applications available to all IMS users, and by doing so provide more than only the basic telecom services like voice, messaging, presence and contact management. However, good knowledge of the IMS network architecture and the underlying Internet protocols is still needed to develop IMS applications. In addition, telecom expertise is needed to deploy the application and provision users. To ease the development and deployment process, it is essential to provide application developers with APIs and similar tools available for Web 2.0 application development today. In this article we explore the architectural and protocol aspects that enable third-party IMS application development and deployment. We also study how the applications will coexist with other applications already deployed in the IMS. Moreover, we describe Java libraries exploiting the functionality of the IMS both in the terminal client and within the core network. We also show how these Java libraries can be used for developing and deploying new applications in an IMS testbed, which provides IMS functionality over commercial 3G networks.

Presence Network Agent: A Simple Way to Improve the Presence Service

The article examines a possible way of improving the performance of the presence service within IMS networks without modifying the presence and group management enabler. This can be achieved by means of a presence network agent (PNA). The PNA has been defined by 3GPP; it is a new logic entity within the IMS core network that is able to publish the presence information on behalf of the presentity user agent. The PNA improves performance because it reduces the presence signaling load within the radio access network without downgrading the freshness and richness of the presence information. The articles goal is to provide the reader with useful information about the PNA and our experience with PNA implementation and deployment. We first describe the PNA concept as defined by 3GPP, highlighting the open issues still present in the standardization and the possible optimizations, subsequently we present an actual implementation of a PNA handling busy/idle states for IMS calls.

Addressing & invocation of IMS-attached services

Services provided by non-IMS enabled platforms (e.g. home electronics, entertainment systems, and various home appliances) are typically not accessible to remote users such as IMS subscribers in spite of the ubiquity of modern mobile communications. This paper outlines an approach for providing IMS based access to such IMS-attached services through mechanisms for their detection, registration, discovery and invocation.

RA-RA: a new bandwidth efficient scheme for movement detection in MIPv6

In networks supporting mobile IP, the address configuration of a mobile node is based on the detection of movement between different subnetworks. The movement detection in wireless IP network is usually performed by means of router advertisement messages. The higher is the rate of these messages, the lower the hand-off delay is and the higher is the bandwidth occupation on the wireless medium. In MIPv6, the interval of the advertisements is randomly varied between MinRtAdvint and MaxRtAdvint. In this paper, we propose and assess rate adjusted-router advertisement (RA-RA), a new mechanism to vary the advertisements rate in order to decrease the bandwidth occupation of these messages while confining part of the L3 handoff setup latency under acceptable values, for instance 15/spl divide/40ms. The benefit on the bandwidth occupation with respect to the MIPv6 technique is 25% /spl divide/ 40%, depending on the interval of advertisements. Our technique is based on the windowing of the RA messages train, each window being placed at the predicted time instants of hand-off arrivals.

Web-based communications [Guest editorial]

Communication is an intensely social activity. Not only do human beings engage in it, but all manner of species depend on communicating intent and information with each other. However, human beings are unique in that we have evolved communications to travel over very long distances. Technology has helped us, from communicating our thoughts on a written medium (papyrus, first manufactured in Egypt as far back as the third millenium BC) to scattering our voice and the written word through ether and light fibers. This, in turn, has enabled us to build special networks optimized for communications. Currently, we are in the throes of a monumental migration in the means of communications, as the incumbent technology (circuit-switched networks that formed the backbone of the public switched telephone network) gives way to a new contender (packet-switched network, or the Internet) [1]. Today, the Internet is the dominant technology over which we communicate our voices, our words, and our images.

Real Time Communications in the Web: Current Achievements and Future Perspectives

The articles in this special section focus on the creation of real-time communication between web browsers via communication standards. These initiatives involve both the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C). The IETF has focused its work on the architecture and on-the-wire protocols, identifying the state information and the events that need to be available to developers, while the W3C worked on application-level JavaScript APIs to be offered to developers in order to allow them to easily implement interoperable real-time multimedia applications in the web. Back in 2011, the IETF chartered the “Real-Time Communication in WEB-browsers” (RTCWEB) Working Group, with the aim of defining an architecture and a complete suite of protocols for the support of real-time multimedia communications directly between browsers. The RTCWEB WG has since worked on key aspects like the overall communication infrastructure, the protocols and API (Application Programming Interface) requirements, the security model, the media formats (and related media codecs), as well as advanced functionality like congestion/flow control and interworking with legacy VoIP equipment. In parallel, the W3C has developed a set of APIs exposing functions like exploration and access to device capabilities, capture of media from local devices, encoding/processing of “media streams,” establishment of peer-to-peer connections between browsers (and web-enabled devices in general), decoding/processing of incoming media streams and delivery of such streams to the end-user in an HTML5-compliant fashion.