Heterogeneous multicast in heterogeneous QoS networks

Supporting heterogeneous receivers in a multicast group is of particular importance in large internetworks as, e.g., the Internet, due to the large diversity of end-system and network access capabilities. Furthermore, it is the nature of large-scale internetworks which makes homogeneous quality of service (QoS) support unrealistic at least for the middle-term future. Therefore, we investigate the implications of differing multicast models in heterogeneous QoS networks. In particular, we approach the problem an edge devices faces when mapping a heterogeneous QoS multicast from an overlaid QoS system onto a system providing only a homogeneous QoS multicast. The generic solution technique we propose for this problem is called foresting. The idea of foresting is to support a heterogeneous multicast by a forest of homogeneous multicast trees. We develop different foresting algorithms and compare them by extensive simulations.