Performance Analysis of a Priority Queue with Session-based Arrivals and its Application to E-commerce Web Servers

Joris Walraevens, Sabine Wittevrongel, Herwig Bruneel
In this paper, we analyze a discrete-time priority queue with a session-based arrival process. We consider an infinitely large user population, where each user can start and end sessions. Sessions belong to one of two classes and generate a variable number of fixed-length packets which arrive to the queue at the rate of one packet per slot. The lengths of the sessions are generally distributed. Packets of the first class have transmission priority over packets of the other class. The model is
more » ... ass. The model is motivated by E-commerce web servers and web servers handling delay-sensitive and delay-insensitive content. By using probability generating functions, performance measures of the queue such as the moments of the packet delays of both classes are calculated. The impact of the priority scheduling discipline and of the session nature of the arrival process is demonstrated. We furthermore use our analysis to provide specific results for an E-commerce web server.