A Queueing System for Modeling a File Sharing Principle

We investigate in this paper the performance of a file sharing principle similar to the one implemented by eMule. For this purpose, we consider a system composed of N peers becoming active at exponential random times; the system is initiated with only one server offering the desired file and the other peers after becoming active try to download it. Once the file has been downloaded by a peer, this one immediately becomes a server. We are basically interested in the transient behavior of this file sharing system, we study the instant when the system shifts from a congested state where all servers available are saturated by incoming demands to a state where a growing number of servers are idle. In spite of its apparent simplicity, this queueing model (with a random number of servers) turns out to be quite difficult to analyze. A formulation in terms of an urn and ball model is proposed and corresponding scaling results are derived. These asymptotic results are then compared against simu...

• Type: Journal
• Year: 2008
• Where: CORR
• Authors: Florian Simatos, Philippe Robert, Fabrice Guillemin
• Keywords: Active Try, CORR 2008, Education, Exponential Random Times, Sharing