Due to increasing computational power, long-life batteries and wireless links with improving bandwidth, distributed multimedia applications have become more and more attractive for mobile users. However, the varying quality of service (QoS) on the wireless link is still a major problem. One generally accepted solution to this problem utilises “proxies” which act on behalf of the mobile user and modify the communication data stream in order to match the current QoS conditions. These proxies are generally dependent on protocol layers, applications or application data. Therefore, in order to enable proxy objects to be flexibly inserted for a given multimedia stream, an architecture is required for managing supplied and installed proxy objects.