Fault-tolerant multi-server video-on-demand service

The work describes three fault tolerant video streaming models for multi-server video-on-demand (VoD) services. These models guarantee continuous streaming to clients despite server failures, while utilizing very low network´s bandwidth and a small client´s buffer. This is achieved by exploiting the special characteristics of the MPEG and Motion-JPEG codecs. The uniqueness of the models suggested here compared to previous research is that, to the best of our knowledge, we are the first to address server failures, rather than only disk or file failures, while trying to take advantage of the codecs used in sending streaming media. In all models there is some degradation in quality until the failure is detected and compensated. However, there are no pauses in the movie, and the degradation in quality is very small compared to the low bandwidth and buffer overhead required, if any.