Linux Firewall-based Embeded Bandwidth Management System

With the develepmonet of network technology, people are experiencing an unprecedented techonology revolution---information revolution. Internet is no longer used only by research organization and education institution. It has become part of people's everyday life. Although China's network infrastructure is changing rapidly, there is still a long way to run for reaching developed countries. While network capacity is far away from people's demands, to ensure the limited network resource is used fairly and efficiently, network traffic control becomes the definite choice. For this purpose, bandwidth management system comes out.This system is a bandwidth based on Linux kernel Netfilter framework. The system consists of three parts: Embedded Linux workstation, traffic differentiating module and bandwidth management module. Embedded Linux can save the requirement of system source, thus reduce cost. In this paper, a mini Linux system is costumed. The main functionality of traffic differentiating modules is to differentiate the traffic and mark them for the use of bandwidth management module. Because of the complication of current network, this module is implemented by traditional ways and content filtering based on protocol analysis, so it can recognize program using dynamic port efficiently. Bandwidth modules uses different polices to different traffic according to the mark traffic differentiating modules provides.This dissertation is organized as follows. The first section talks about the research background and the necessity of the system. In section two the involved technology is reviewed. The design of the system is argued in section three. The way to construct embedded Linux system is talked about in section four. In section five the implementation of the system is commented. Section six concludes the dissertation and gives the advantages and disadvantages of the system.