We present the first broadcasting protocol that can alter the number of channels allocated to a given video without inconveniencing the viewer and without causing any temporary bandwidth surge. Our <i>variable bandwidth broadcasting </i>(VBB) protocol assigns to each video a minimum number of channels whose bandwidths are all equal to the video consumption rate. Additional channels can be assigned to the video at any time to reduce the customer waiting time or retaken to free server bandwidth. The cost of this additional flexibility is quite reasonable as the bandwidth requirements of our VBB fall between those of the <i>fast broadcasting </i>protocol and the <i>new pagoda broadcasting</i> protocol.
We propose a reactive broadcasting protocol that addresses the problem of distributing moderately popular videos in a more efficient fashion. Like all efficient broadcasting protocols, reactive broadcasting assumes that the customer set-top box has enough local storage to store at least one half of each video being watched. Unlike other broadcasting protocols, reactive broadcasting only broadcasts the later portions of each video. the initial segment of each video is distributed on demand using a stream tapping protocol. Our simulations show that reactive broadcasting outperforms both conventional broadcasting protocols and pure stream tapping for a wide range of video request rates.
Broadcasting protocols can improve the efficiency of video on demand services by reducing the bandwidth required to transmit videos that are simultaneously watched by many viewers. It has been recently shown that broadcasting protocols using a very large number of very low bandwidth streams for each video required less total bandwidth than protocols using a few high-bandwidth streams shared by all videos. We present a hybrid broadcasting protocol that combines the advantages of these two classes of protocols. Our pagoda broadcasting protocol uses only a small number of high-bandwidth streams and requires only slightly more bandwidth than the best extant protocols to achieve a given maximum waiting time.