A Campus Network Accouting System Based On Transparent Gateway

With the popularization and development of campus network, many kind of accounting systems have been designed to guarantee the operation of it . And the technologies used in it have changed gradually, especially the method of flow collecting. In this thesis, a kind of accounting system based on transparent gateway was designed and finished which has some merits, for example, user-based, user-transparence and quick forwarding speed and so on. The integrated IP packet can be caught by the transparent gateway, so the accounting system can not only billing network usage by a person but also controlling the action of user and monitoring network performance. In this article, some flow data collecting modes are studied and the mode based on transparent gateway is researched on emphasis. Then an improved transparent gateway (kernel-space transparent gateway) were put forward, grounded on the traditional transparent gateway (user-space transparent gateway) and a firewall framework called Netfilter imbedded in Linux2.4 Kernel. In such kind gateway the procedures located in kernel, the function of data packet forwarding act on network layer. So the performance of it improved greatly.Grounded on the traits of improved transparent gateway, combining database and active pages technologies, the accounting prototype system based on transparent gateway is finished, and the system's performances are tested. The result shows that the performance of accounting system based on kernel-space gateway is superior to the one that based on user-space gateway.