Context-aware multiparty services delivery: Evaluation and experimentation

This paper addresses the challenge of enabling efficient multimedia group communications in today's highly heterogeneous networking environment. In particular, such an environment calls for a multiparty delivery solution capable of finding an optimal balance between two apparently contradictory needs: on one hand personalizing the service delivery for each user based on his particular context to offer the desired quality of experience, and on the other hand optimizing network resources by maximizing the use of traffic aggregation techniques like IP multicast when possible. The proposed context-aware multimedia multiparty delivery architecture reaches this objective by optimizing the service delivery for each user through dynamic adaptations at the session, transport, and network layers. These adaptations encompass means for dynamic selection of the best user device (if multiple are available), media coding, access network, routing path, transport connection type, transport reliability scheme, and QoS support. Both the networking context of the user and his environmental context (typically acquired from sensors) are taken into account in that process. In particular, the architecture (a) enables dynamic clustering of users with similar contexts into subgroups receiving the same content but in different formats (e.g. different media codings); and (b) for each subgroup it builds a QoS-enabled multiparty transport overlay tree maximizing the use of IP multicast when available for efficient use of network resources. This architecture has been validated and evaluated both through simulation and prototyping; and the results obtained are presented hereunder.