DCON (Distributed CONferencing) is an actual implementation of a distributed web conferencing architecture we defined. It's compliant with the IP Multimedia Core Network Subsystem (IMS) specifiation and has been conceived to be highly reliable and scalable. Its name explicitly recalls the XCON model. DCON is in fact based on the idea that a distributed conference can be setup by appropriately orchestrating the operation of a set of XCON focus elements, each in charge of managing a certain number of participants distributed across a geographical network. At its current state, it is capable to provide to each focus the conferencing information about the remote "islands" recognized as "active" on the base of the user presence. The users can so join both local and remote conferences in a transparent fashion.
On the client side, instead, we adopted Spark, an open source XMPP client, which we made DCON-enabled and capable to schedulate new conferences and join existing ones by means of an ad hoc modified version of MjSip, a complete java-based implementation of a SIP stack. In such a way we provide an unified client for telephony and instant messaging.