Lorenzo Miniero

On the seamless interaction between webRTC browsers and SIP-based conferencing systems

The growing interest in integrating interactive multimedia features into web applications has recently led to the creation of the W3C WebRTC and the IETF RTCWEB working groups. Such groups are jointly defining both the application programming interfaces and the underlying communication protocols for the setup and management of a reliable communication path between any pair of next-generation web browsers. While the ongoing work is focusing on peer-to-peer communication between browsers, engineers are also facing a new issue, associated with the coexistence of legacy SIPbased systems with the upcoming browserenabled architectures. We herein discuss how we tackled such an issue, by first identifying interoperability requirements and then presenting a real-world interoperability example dealing with the integration of RTCWEB clients into an existing standards-based collaboration platform.

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

Improving the scalability of an IMS-compliant conferencing framework through presence and event notification

In this article we present a thorough performance analysis of an actual implementation of a distributed conferencing framework compliant with the IP multimedia core network subsystem specification. The subject of our experimental campaign has been an architecture implemented by exploiting existing achievements in the field of conferencing. The work presented is based on the standard centralized conferencing framework defined by the IETF XCON working group, for which we recently provided an open source implementation. Starting from here, we devised a distributed conferencing solution that has been implemented as an overlay network of centralized conferencing clouds able to: (i) discover each other by means of presence mechanisms; (ii) exchange conference related information through an event notification paradigm; (iii) manage distributed conferences through out-of-band dedicated channels. The study is conducted by first measuring the main performance figures of the centralized solution and then assessing the capability of the distributed framework to improve such performance by scaling both in the number of supported users/conferences and in the overall resource consumption.

Janus: a general purpose WebRTC gateway

This paper deals with the design and implementation of Janus, a general purpose, open source WebRTC gateway. Details will be provided on the architectural choices we took for Janus, as well as on the APIs we made available to extend and make use of it. Examples of how the gateway can be used for complex WebRTC applications are presented, together with some experimental results we collected during the development process.

Performance analysis of the Janus WebRTC gateway

This paper takes an in-depth look at the performance of the Janus WebRTC gateway. Janus is a modular, open-source gateway allowing WebRTC clients to seamlessly interact with legacy real-time communication technologies, both standard and proprietary, and with each other. This is achieved by attaching technology-specific plugins on top of a barebones core implementing all of the functions and protocols mandated by the RTCWEB/WebRTC specification suites. The paper focuses on assessing the scalability of the Janus architecture, by selecting three representative use cases, followed by a detailed analysis of a real-world scenario associated with multi-point audio conferencing.

Improving the Scalability of an IMS-Compliant Conferencing Framework Part II: Involving Mixing and Floor Control

At IPTComm 2007 we presented a paper in which we analyzed the performance of a distributed conferencing framework we have recently designed and implemented. The paper focused on the scalability of the overall framework and demonstrated that the switch from a centralized to a distributed approach can significantly improve the achievable performance. Though, in the cited work, we mainly addressed the signalling aspects of the framework. We did not make any attempt at assessing the performance of our architecture (neither in the centralized, nor in the distributed case) in the presence of mixed media streams. This left us, and perhaps the readers, with a fine sensation of unfinished and motivated us to keep on working on the measurements, this time focusing on the two main aspects that come into play when a real conference is activated in a moderated environment like the one we propose: (i) mixing of the real-time streams generated by the users; (ii) floor control.

Design and implementation of an open source IMS enabled conferencing architecture

In this paper we embrace an engineering approach to service delivery over the Internet, by presenting an actual implementation of a conferencing framework compliant with the IP Multimedia Core Network Subsystem (IMS) specification. The architecture we describe has been conceived at the outset by taking into account ongoing standardization efforts inside the various active international bodies. At its current state, it is capable to provide video conferencing facilities with session management capabilities and floor control. The system presented is intended to serve as a running experimental testbed useful for protocol testing, as well as field trials and experimentations. It will be first described from a high level design perspective and subsequently analyzed in further detail by highlighting the most notable implementation choices. A mapping between the actual system components and the corresponding IMS logical functions will be provided and a discussion concerning those parts of the system which somehow depart from the IMS paradigm will be conducted. This on one hand will help the reader figure out potential discrepancies between our solution and the IMS model; on the other hand will open space for discussion around some important open issues on which the international research community still has to attain a rough consensus.

Meetecho Mobile: Accessing an IETF-compliant conferencing framework from cellular devices

In this article we present Meetecho Mobile, an innovative conferencing client designed for mobile devices. Such a client provides access to conferences compliant with the most recent standard proposals currently under definition within the IETF. It allows mobile users to participate in multimedia conferences involving, besides an XMPP-based chat, both audio and video streams. The article discusses the design and implementation of the conferencing client and highlights the most notable solutions we devised in order to effectively handle a whole suite of protocols, ranging from signaling (SIP/SDP, XMPP) to real-time streaming (RTP). We also provide information about the main performance figures characterizing the clients behavior.

CCMP: a novel standard protocol for conference management in the XCON framework

This paper presents the design and implementation of CCMP, a conference management protocol currently under standardization within the IETF, conceived at the outset as a lightweight protocol allowing conferencing clients to access and manipulate objects describing a centralized conference. The CCMP is a state-less, XML-based, client-server protocol carrying in its request and response messages conference information in the form of XML documents and fragments conforming to the centralized conferencing data model schema. It represents a powerful means to control basic and advanced conference features such as conference state and capabilities, participants and relative roles and details. We first focus on the design of the protocol and then discuss how it has been integrated in the Meetecho collaborative framework developed at the University of Napoli as an active playground for IETF standardization activities in the field of real-time applications and infrastructure.

Standard multimedia conferencing in the wild: the Meetecho architecture

We present a conferencing architecture called Meetecho. To the purpose, we embrace an engineering approach, by describing an actual implementation of an open source centralized video-conferencing system capable to offer advanced communication experience to end-users through the effective exploitation of mechanisms like session management and floor control. Meetecho has been designed to be fully compliant with the latest standard proposals coming from both the IETF and the 3GPP and can be considered as an outstanding example of a real-time application built on top of the grounds paved by the SIP protocol. We will discuss both the design of the overall conferencing framework and the most important issues we had to face during the implementation phase.