Multi-level reliability in multimedia collaboration over heterogeneous networks

Recently there has been great interest in multimedia collaboration over the Internet to support teamwork without the need for geographical and/or time proximity. Different collaborative scenarios require different communication characteristics. Besides unreliable and reliable communications, some collaborative applications can benefit from partially reliable communication, especially in heterogeneous networks. This leads to the concept of multilevel reliability. The concept of partial reliability and spiral multicast for achieving partially reliable communication are presented. Unlike reliable multicast, spiral multicast consumes less bandwidth, has faster response time, and does not suffer from the implosion problem. Architecture and performance studies of multi-level reliability in multimedia collaboration are presented.