A comparative analysis of server selection in content replication networks

Server selection plays an essential role in content replication networks, such as peer-to-peer (P2P) and content delivery networks (CDNs). In this paper, we perform an analytical investigation of the strengths and weaknesses of existing server selection policies, based initially on an M/G/1 Processor Sharing (PS) queueing-theoretic model. We develop a theoretical benchmark to evaluate the performance of two general server selection policies, referred to as EQ DELAY and EQ LOAD, which characterize a wide range of existing server selection algorithms. We find that EQ LOAD achieves an average delay always higher than or equal to that of EQ DELAY. A key theoretical result of this paper is that in an N-server system, the worst-case ratio between the average delay of EQ DELAY or EQ LOAD and the minimal average delay (obtained from the benchmark) is precisely N. We constructively show how this worst-case scenario can arise in highly heterogeneous systems. This result, when interpreted in the ...

• Type: Journal
• Year: 2008
• Where: TON
• Authors: Tao Wu, David Starobinski
• Keywords: EQ DELAY, EQ LOAD, Server Selection, TON 2008