The book provides a comprehensive investigation of the performance and problems of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol stack, when data is transmitted over GSM, GPRS and UMTS. It gives an introduction into the protocols used for Internet access today and briefly into the Wireless application Protocol, WAP. The basics of GSM, GPRS and UMTS are given necessary for understanding the main topic, TCP performance over GSM, GPRS and UMTS. We then describe at length the problems that TCP has when operating over a mobile radio link, and what has been proposed to remedy these problems. We derive the optimum TCP packet length for maximum data throughput on wireless networks, analytically and by simulation. Results on the throughput and various other parameters of TCP over mobile networks are given. This book gives valuable advice to network operators and application programmers how to maximise data throughput, and which protocols, transmission modes, and coding schemes to prefer and which to avoid to achieve this goal.