Wireless Internet

Wireless Internet access has recently gained significant attention as wireless/mobile communications and networking become widespread. Voice over IP service is likely to play a key role in the convergence of IP based Internet and mobile cellular networks. The mobility management performance for Mobile IP and Session Initiation Protocol is the focus of this thesis. After illustrating the operation of the protocols, the discrete event simulator, Network Simulator 2 (ns2), is used to compare the performance of the two protocols. The comparison of the protocols is done by comparing average end-to-end delay and the ratio of the number of packets received to the number of packets originally sent (Packet Delivery Fraction). The impact of mobility is analyzed by studying the performance of the protocols, for various mobility scenarios. The effect of an increase in the number of nodes and increase in velocity of the mobile node on the performance of the Mobile IP and SIP is compared. The performance of the Mobile IP and SIP is compared by measuring the performance metrics of the two protocols for similar simulations. The results obtained as a result of the simulations leads us to some interesting conclusions.

As Wireless appliances become more common place we are beginning to experience multiple problems. We are experiencing interoperability problems related to devices' capabilities in relation to applications, along with network/application services limitations for understanding the diversity among these devices. In this thesis the issues related to Location Discovery, Location Management and Device capabilities are discussed. Solutions based on current technologies, including Triangulation and GPS, are discussed for Location Management along with the concepts of Location Tracking and Location Modeling for increasing the effectiveness of Location Management technologies. Finally an XML based Language is presented which affords generality for User to Network and Network to User communication for the many wireless devices.

The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite, which is used by major Internet applications such as World Wide Web, email, remote administration and file transfer. TCP implements scalable and distributed end-to-end congestion control algorithms to share network resources among competing users. TCP was originally designed primarily for wired networks, and it has performed remarkably well as the Internet scaled up by six orders of magnitude in the past decade. However, many studies have shown that the unmodified standard TCP performs poorly in networks with large bandwidth-delay products and/or lossy wireless links. In this thesis, we analyze the problems TCP exhibits in the wireless communication environment, and develop joint TCP congestion control and wireless-link scheduling schemes for mobile applications. ... Different from the existing solutions, the proposed schemes can be asynchronously implemented without message passing among network nodes; thus they are readily deployable with current infrastructure. Moreover, global convergence/stability of the proposed schemes to optimal equilibrium is established using the Lyapunov method in the network fluid model. Simulation results are provided to evaluate the proposed schemes in practical networks.