Informing Clients through Multimedia Communications: An approach to provide interactivity

One of the key problems in informing clients through multimedia streaming applications over the Internet is to customize the stream of information according to the client’s requests. This is achievable only if client and server can interact along the application lifetime, which is possible only if the communication system supports the rigid timing constraints imposed by these interactive applications on their traffic. In the Internet scenario, these applications are very difficult to support, as the Internet provides a best-effort service to the traffic it carries, which means that the Internet does not make any promises about the end-to-end delay for an individual packet and about the variation of packet delay (network jitter) within a packet stream. These problems are confirmed by several experiments we performed over the Internet, which highlight that interactive applications achieve a quality that is frustrating. The contribution of this paper is the proposal of a novel mechanism to support interactive multimedia streaming applications over the Internet. Our mechanism adapts the multimedia stream transmission to the network conditions, by intentionally and slightly acting on the video QoS. Our mechanism has been validated through severalexperiments performed over the Internet. Results confirm that the supported interactive applications achieve a satisfactory quality and the user perceives a video quality only slightly affected by the QoS modification introduced by our mechanism.