Emerging wireless networks are characterized by increased heterogeneity in wireless access technologies as well as increased peer-to-peer communication among wireless hosts. The heterogeneity among wireless access interfaces mainly exists because of the fact that different wireless technologies deliver different performance trade-offs. Further, more and more infrastructure-less wireless networks such as ad-hoc networks are emerging to address several application scenarios including military and disaster recovery. These infrastructure-less wireless networks are characterized by the peer-to-peer communication model. In this thesis, we propose transport protocols that tackle the challenges that arise due to the above-mentioned properties of state-of-the-art wireless data networks. The main contributions of this work are as follows: 1. We determine the ideal nature and granularity of transport adaptation for efficient operation in heterogeneous wireless data networks by performing comprehensive experimental analysis. We then design and implement a runtime adaptive transport framework, *TP, which accommodates the capabilities of the ideal transport adaptation solution. 2. We prove that conversational transport protocols are not efficient under peer-to-peer wireless data networks. We then design and implement NCTP which is a non-conversational transport protocol.

Internet Access logs in a local area network are the most prominent records when the source of an Internet event is traced back. Especially in a case where an illegal activity having originated from your local area network is of concern, it is highly desirable to provide healthy records to the court including the source user and machine identity of the log record in question. To establish the validity of user and machine identity in the log records is known as source authentication. In our study, after the problem of source authentication in each layer is discussed in detail, we argue that the only way to establish a secure source authentication is to implement a system model that unifies low level and upper level defense mechanisms. Hence, in this thesis we propose an Unauthorized Internet Access Blocking System validating the Source Information in Internet Access Logs. The first version of our proposed system, UNIDES, is a proxy based system incorporating advanced switches and mostly deals with the low level source authentication problems. In the second version, we extend our system with SIACS which is an Internet access control system that deals with the user level source authentication problems. By supplementing the classical username-password authentication mechanism with SSL client authentication, SIACS integrates a robust user level authentication scheme into the proposed solution.

The advent of Internet, the phone mobile and the globalization have modified the forms of communication in the world and the enterprises in general. All this has brought the search of facilities of communications permanents, mobilities and secures with quality of service to improve the Internet and the new aplications on devices mobile. The studies of the new protocol of internet as Ipv6 are in a proces that consist in finding new focus to improve the quality of service. This thesis consists in analyzing and give recomendations of Ipv6 with Business Intelligence to demonstrate that the use improve the management in the enterprises. Ipv6 is the best solution to improve the throughput in the network. The other side, it proposes a new way of business on internet y the born the new aplications as for example the m-commerce and Business Intelligence since any devices mobile.

<p>The most widely used protocol for providing reliable service and congestion control in the Internet is the Transmission Control Protocol (TCP). When the Internet is moving towards more use in mobile applications it is getting more important to know how TCP works for this purpose.</p><p>One of the technologies used for mobile Internet is the Enhanced General Packet Radio Service (EGPRS) extension to the popular GSM system. This thesis presents a low-level analysis of TCP performance in an EGPRS system and an overview of existing TCP, GSM and EGPRS technologies.</p><p>The bottleneck in an EGPRS system is the wireless link – the connection between the mobile phone and the GSM base station. The data transfer over the wireless link is mainly managed by the complex RLC/MAC protocol.</p><p>In this thesis, simulations were made to identify some problems with running TCP and RLC/MAC together. The simulations were made using existing EGPRS testing software together with a new TCP module. The simulation software is also briefly described in the thesis.</p><p>Additionaly, some suggestions are given in order to enhance performance, both by changing the EGPRS system and by modifying the TCP algorithms and parameters.</p>

Les réseaux de communication offrent à ce jour un ensemble de services très<br />diversifié aussi bien pour les industriels, les banques, la recherche, pour des particuliers et récemment<br />dans la médecine et la commande à distance. A cette forte utilisation des réseaux<br />viennent s'ajouter des contraintes de performances, de sécurité et de qualité de service que les<br />fournisseurs de service se doivent de respecter. L'étude des performances des réseaux ainsi que<br />leur modélisation exacte est donc un pas important pour la connaissance des influences des<br />différents liens des lignes de transmission sur les données qui les traversent. Afin d'évaluer l'in-<br />fluence des réseaux de communication dans la transmission des données, nous proposons de<br />modéliser puis d'étudier une ligne de transmission TCP/IP soumise aux protocoles de contrôle<br />de congestion et plongée dans un environnement Internet. L'outil de modélisation utilisé est les<br />RdP hybrides. Un modèle a été établi à base duquel toutes les dynamiques peuvent être observées<br />à tous les niveaux d'une communication (charge des buffers, baisse des vitesses à l'entrée<br />des routeurs, séparation des flux par les routeurs, priorités, stockage des données, retards, pertes,<br />etc.). Ce modèle détaillé nous a aussi permis de visualiser directement l'effet des changements<br />de paramètres de la ligne et des protocoles sur l'évolution de la transmission sur la ligne : Un<br />large panel de simulations a donc été effectué afin de visualiser ces différentes performances.<br />Enfin, un travail d'amélioration du temps de détection des pertes sur une ligne a été effectué.

Thèse de doctorat : Informatique : Nice : 2006. / Bibliogr. p. 147-154. Résumés en français et en anglais.

Thesis (M.S.)--Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: PI; PISA; PIMC; cwnd; TCP. Includes bibliographical references (p. 49-50).

Thesis (Ph. D.)--Mississippi State University. Department of Computer Science and Engineering. / Title from title screen. Includes bibliographical references.

Thesis (M.S.) -- Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.