 This assumption is based on the idea of having a flow control (like TCP mechanisms) which adapts the flow of packets to the available bandwidth. According to different networks, a variety of statistical distributions can be used. Packet size The packet size is a random variable with the mean packet size UPS. The following table summarizes the web traffic models defined by the European Telecommunications Standards Institute (ETSI) [ETSI01], Mobile Wireless Internet Forum (MWIF) [MWIF01] and the MOMENTUM project [TWP*02]. Model Momentum Parameters Project Packet call Inter Geometric Exponential Exponential arrival Time distribution distribution distribution (Reading Time) MIAT = 5 seconds MIAT = 12 seconds MIAT = 412 seconds Packet call size Pareto Distribution (Number of packets (Number of Parameters: ) X (Mean Packet packets ) X (Mean x=1.1, k=4.5 Kbytes, sizes in a Packet Packet sizes in a m=2 Mbytes call) Packet call) u= 25 Kbytes u= 25 X 480bytes u = 25 X 480 bytes = 12 Kbytes = 12 Kbytes Packet sizes with Constant Pareto distribution Pareto distribution in a Packet call (MTU size) parameters: parameters: x=1.1, k=81.5 bytes, a=1.1, k=81.5 bytes, 1500 bytes m=66.666 Kbytes m=66.666 Kbytes UPS 480 bytes UPS = 480 bytes Number of Based on packet Exponential Geometric packets in a call size and the distribution distribution packet call packet MTU Up = 25 packets Up = 25 packets Table 5.3: Traffic models for web application 5 Introduction of Simulation Models In the above table, all the three traffic models apply the truncated Pareto distribution (Pareto with cut-off) for modeling the packet or packet call size. The probability density function of such a truncated Pareto distribution is given by: (5.2) Where k is the location parameter and a is the shape parameter, and m denotes the maximum value. Here B is the probability forxm, calculated as follows: (5.3) Then the mean packet size UPS can be calculated by: (5.4) Comparing these three traffic models, it is found that the web traffic model defined by ETSI genera