Adaptive QoS management for collaboration in heterogeneous environments

Adaptive Quality-of-Service management is critical for enabling effective collaboration between distributed clients in a heterogeneous (wired and wireless) environment. This is because both client profiles (capabilities, interests and resources) and system resources can be significantly different and highly dynamic. This paper presents the design and prototype implementation of an adaptive QoS management framework for collaborative multimedia applications in distributed, heterogeneous environments. The overall goal of the framework is to locally adapt the shared information to meet the capabilities, interests and current state of each collaborating client while preserving the semantic content of the information to maintain effective sharing. Transformations investigated in this paper include gradual gradations and modality transformations. The framework builds on a publisher-subscriber messaging substrate that uses semantic profiles and provides each client with direct and immediate access to all information defined by its needs and capabilities, without having to maintain and update global rosters. It interfaces with the Simple Network Management Protocol (SNMP) to determine the state of the network by directly querying network elements. An experimental evaluation of the framework for wired and wireless clients is also presented.