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Mathematical Problems in Engineering
Volume 2014, Article ID 920829, 13 pages
Research Article

Dynamic Request Routing for Online Video-on-Demand Service: A Markov Decision Process Approach

1Inner Mongolia University of Technology, Hohhot 010051, China
2Liaoning Technical University, Fuxin 123000, China

Received 22 January 2014; Accepted 4 May 2014; Published 1 June 2014

Academic Editor: Guoqiang Hu

Copyright © 2014 Jianxiong Wan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We investigate the request routing problem in the CDN-based Video-on-Demand system. We model the system as a controlled queueing system including a dispatcher and several edge servers. The system is formulated as a Markov decision process (MDP). Since the MDP formulation suffers from the so-called “the curse of dimensionality” problem, we then develop a greedy heuristic algorithm, which is simple and can be implemented online, to approximately solve the MDP model. However, we do not know how far it deviates from the optimal solution. To address this problem, we further aggregate the state space of the original MDP model and use the bounded-parameter MDP (BMDP) to reformulate the system. This allows us to obtain a suboptimal solution with a known performance bound. The effectiveness of two approaches is evaluated in a simulation study.