Designation And Implementation Of Intranet Bandwidth Management Based On Linux QoS

With the rapid development of network applications, the demand of the network bandwidth is becoming greater than ever before. If we do not make proper plans to the intranet bandwidth management, it will easily cause the network congestion and the QoS of some important intranet users will not be guaranteed. According to this situation, an intranet bandwidth management system has been designed. First, The intranet administrator can know the usage of the intranet bandwidth through the traffic statistics, then he could make plans by the priority of each user and the time whether rush hours or not, these plans include limiting the max-available bandwidth, guaranteeing the mini-available bandwidth and letting the users share the idle bandwidth to make full use of it.Netfilter is a packet filter system of the Linux kernel, it can determine the packets where to go by checking the header of each packet. Iptables is a program of userspace corresponding Netfilter of the kernel. By setting new rules in Iptables can change the default direction of packets in Netfilter. There are also packet counters in Iptables, so we can gather the statistics of how many packets and how much flow have passed a particular chain. In the paper, we change the direction of the packets by creating new chains and rules based on different source/destination ip addresses and port numbers, and gather the statistics in the chains which the packets have passed by, finally draw the statistics graphs of each user ip address.Linux QoS is a kind of effective bandwidth management mechanism including the qdiscs, filters and classes. The qdiscs decide the output order of the packets. The filters lead the packets to proper classes by checking the filter rules. In this paper, we first create classes based on different ip addresses, and set qdiscs in the classes, including setting the priority of the class to determine the order of obtaining the bandwidth and how much bandwidth it can obtain. Then we set the filter rules to lead different user packets to different classes.Besides the traditional filter rules which are based on ip addresses and port numbers, this paper introduces a new method to filter the application layer protocol packets which is based on regular expressions. We also add the time factor to the system, we can choose when to turn the bandwidth management on and when to trun it off, the time factor gives more flexibility to the system.