On proxy server based multipath connection

A multipath connection provides multiple paths among network hosts. The traffic from a source can be spread over multiple paths and transmitted in parallel through the network. The receiver collects the incoming network packets, re-assembles them, and delivers them to the upper-level end users. Multipath connections offer applications with the ability to improve network performance, security and reliability.; In this dissertation, techniques for supporting the proxy server based multipath connection (PSMC) are studied. First, the design and implementation of a proxy server based overlay network using a set of intermediate connection relay proxy servers is presented. Multiple indirect alternate paths can be set up via these proxy servers. The proxy server based overlay network is used in a Secure Collective Defense system (SCOLD) to defend against Distributed Denial of Services (DDoS) attacks. The Berkeley Internet Name Domain (BIND - v.9) package is enhanced to support indirect routing with IP Tunneling. The performance of the SCOLD system validates the capability of PSMC in enhancing the network security.; Second, the existing TCP/IP protocol is enhanced with a proxy server based multipath protocol (PSMP). On the sender side, the IP layer is enhanced to distribute packets across multiple paths. The TCP congestion window control is revised for higher throughput. On the receiver side, the TCP layer is enhanced with a double buffer to solve the persistent reordering problem. Detailed analysis of the PSMP is presented. A communication channel is set up between the sender and the receiver for exchanging network traffic information. The enhancement supports both Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).; Third, proxy server selection algorithms are developed for selecting a subset of proxy servers from a large set of available proxy servers with various object functions and constraints.; Fourth, resource allocation schemes are proposed and implemented on the end server to provide proportional differentiated services. These schemes are based on the queueing theory and feedback control theory. By combining the multipath on the network with service differentiation at the end server, a comprehensive solution for various QoS and security related applications can be provided.; PSMC utilizes existing network protocols and infrastructure with some enhancements. This ensures the ease of its deployment with the current Internet in various network environments. Therefore, a large number of applications could benefit from utilizing PSMC. The research results and insight obtained from PSMC could have broader impact on the protocols and security in today's Internet.