TCP/IP (Computer network protocol)

With the explosive growth of the Internet and other types of networks, such as cell phones and pager networks, more and more people expect to communicate with each other personally anywhere and at anytime. This thesis studies a new architecture Mobile People Architecture (MPA) proposed by MosquitoNet research group at Stanford University, which is designed to put people, rather than the devices that people use, at the endpoints of communication session. Three usage scenarios in MPA are simulated using SES/Workbench. The Response Time and the Update Cost are used to evaluate the performance of above scenarios. The advantages and disadvantages of different scenarios are also analyzed and discussed in this thesis.

In this present computer age, cellular technology and portable computers are becoming an integral part of day to day life. Each computer user wants to access the computing resources, irrespective of the location. Because of this need the computing paradigm "Mobile Computing" has assumed a primary role in modern computer communication technology. There are different Internet protocols proposed for Mobile Computing. In the present research, we study the Internet Engineering Task Force (IETF) Mobile IPv6 (new version of current IPv4 protocol). We have developed simulation program using Scientific and Engineering Software (SES/workbench) and studied three mobility patterns namely Travelling Salesman, Pop-Up and Boring Professor for the performance study of Mobile IPv6. Performance of Mobile IPv6 is measured in terms of utilization and overhead and compared with Mobile IPv4 and Basic Triangular Routing (BTR). It has been observed that Mobile IPv6 scheme has better route optimization than the other schemes when Mobile node's movement from one network to another network is less frequent. But, when the movement of the Mobile node is more frequent then Basic Triangular Routing scheme outperformed the Mobile IPv6 scheme.

A promising next-generation version of service that could be availed from local exchange carriers (LECs) refers to streaming Internet protocol based television (IPTV) programs into subscriber premises via traditional copper pairs. The present study addresses provisioning economically-budgeted and optimally-engineered bit rates (EBRs) in implementing IPTV technology in the local-loop via copper-pairs using the so-called (ADSL2/ADSL2+) technology (with high-speed/large bandwidth considerations plus copper-bonding for bandwidth sharing capabilities). Also studied is the way to extend the backhaul transport of IPTV on copper-lines (plus any other local-loop transmissions that may co-exist) onto an "all-optical" trunk of the inter-office facilities (IOFs) in the edge/core network cloud of the telcos. A model of a core network topology is analyzed for traffic considerations so as to decide on blocking probability at a specified egress node under different conditions of burstiness. The problems posed are analyzed via computations/simulations on Matlab(TM) (v6.5). Inferential remarks are gathered, conclusions are drawn and open-questions yet to be researched are indicated.

IP address autoconfiguration poses a challenge for mobile ad-hoc networks (MANETs) because it has to be done to ensure correct routing. An IP autoconfiguration protocol that is based on quorum voting is proposed. Nodes are distributed configured when a write quorum can be collected. Making the compromise between message overhead and data consistency, quorum voting enforces data consistency by ensuring fresh read on every access so that each node is configured with a unique IP address. The protocol is scalable since the configuration information is maintained locally and no central server is involved. Extensive experiments are carried out comparing the configuration latency, message overhead and address reclamation cost between our protocol and existing stateful protocols. The simulation results show that nodes are configured in lower latency and the message overhead for maintaining the network is fairly low. Moreover, the proposed protocol greatly enhances the address availability by keeping proper redundancy.

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.

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.

The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. In the wired network, TCP performs remarkably well due to its scalability and distributed end-to-end congestion control algorithms. 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 and develop TCP congestion control algorithm for mobile applications. We show that the optimal TCP congestion control and link scheduling scheme amounts to window-control oriented implicit primaldual solvers for underlying network utility maximization. Based on this idea, we used a scalable congestion control algorithm called QUeueIng-Control (QUIC) TCP where it utilizes queueing-delay based MaxWeight-type scheduler for wireless links developed in [34]. Simulation and test results are provided to evaluate the proposed schemes in practical networks.

The IP Multimedia Subsystem (IMS) has gone from just a step in the evolution of the GSM cellular architecture control core, to being the de-facto framework for Next Generation Network (NGN) implementations and deployments by operators world-wide, not only cellular mobile communications operators, but also fixed line, cable television, and alternative operators. With this transition from standards documents to the real world, engineers in these new multimedia communications companies need to face the task of making these new networks secure against threats and real attacks that were not a part of the previous generation of networks. We present the IMS and other competing frameworks, we analyze the security issues, we present the topic of Security Patterns, we introduce several new patterns, including the basis for a Generic Network pattern, and we apply these concepts to designing a security architecture for a fictitious 3G operator using IMS for the control core.