Admission control policies for video on demand brokers

A VOD server has to employ admission control algorithms to decide whether a new client (request) can be admitted without violating the requirements of clients who are already being serviced. This paper presents and analyzes four specific admission control algorithms pertaining to the deterministic and predictive category. These algorithms are: maximum, adaptive maximum, average and adaptive average. They are studied in detail for CPU and network resources. The adaptive algorithms are our own contribution and we show that they use an exponential weighted average to guess the future resource needs of a stream, rather than just using the maximum or mean over the whole period. Thus, they provide smoothing and so a closer matching of resources used to those reserved and so higher capacity and less waiting time.