Load shift protocol design in ATM-based VOD systems

Load shift is a basic operation for load balancing algorithms. In this paper, we study the load shift problem in an ATM-based distributed video-on-demand (VOD) system. Two different system configurations are considered for the load shift. One allows more than one video streams being active simultaneously from multiple video servers to a set-top box (STB), in which no-gap load shift is possible. The other one allows only one video stream between a STB and the VOD system. With respect to this case, two transport schemes are proposed: control with load shift (DRCLS) and constant rate control with load shift (CRCLS). For DRCLS, new water lines of the STB buffer have to be specified for flow control in cases of load shifts. For CRCLS, we compute the new feasible parameter set, which includes the required bandwidth, the minimal STB buffer size and the pre-download time. Finally, we compare the differences between DRCLS and DRCLS.