Tune to Lambda patching

Abstract

A recent paper by Hua, Cai and Sheu [7] describes Patching as a technique for reducing server load in a true video-on-demand (TVoD) system. It is a scheme for multicast video transmissions, which outperforms techniques such as Batching in response time and Piggybacking in bandwidth savings for titles of medium popularity, and probably in user satisfaction as well. It achieves TVoD performance by buffering part of the requested video in the receiving end-system.In a further study, the authors give analytical and simulation details on optimized patching windows under the assumptions of the Grace and Greedy patching techniques. In our view, this does not exploit fully the calculation that was performed in that study. We state that temporal distance between two multicast streams for one movie should not be determined by a client policy or simulation. Rather, it can be calculated by the server on a per video basis, since the server is aware of the average request interarrival time for each video. Since we model the request arrivals as a Poisson process, which is defined by a single variable that is historically called λ, we call this variation "λ Patching". Furthermore, we present an optimization option "Multistream Patching" that reduces the server load further. We accept that some near video-on-demand-like traffic is generated with additional patch streams, and achieve additional gains in server load.