Research And Implementation On Load Balance Under Multi NIC Linux Server

As long as network traffic increasing rapidly and the network structure becoming more complex, the possibility of load imbalance and network congestion becomes larger. If we can not control the load balance effectively, it will result in load imbalance and network congestion, and waste resources . Thus, load balance technologies become one of the hot research topics in the area of computer networks.There are two aspects on load balance technologies: load balance in a single server cluster and load balance in single server with multi-NIC(Network Interface Card).This paper firstly introduces the basis conception and theory of load balance and high availability technologies, and studies load balance technologies for server clusters, especially the theory and schedule algorithms of LVS(Linux Vitual Server).This paper then focuses on technologies of Linux bonding and load balance in single server with multi-NIC. Linux bonding is realized through the vitual NIC software between NIC drive and data link software. In this way, multi-NIC is bond not only to single IP address but also to single MAC address. Thus, a virtual NIC is formed. The virtual NIC can schedule network traffic to particular physical NIC according to a certain algorithm, realize load balance and increase server throughput and server availability.This paper finaly analyses several existing load balance algorithms of the Linux bonding and their shortcomes, and puts forward three new load balance algorithm based on TCP/IP protocol. The first is based on ip stream, this algorithm decides sending interface according to its destination ip and source ip; the second is based on tcp stream , This algorithm decided data packet's sending interface according to its destination ip address,its subnet and its destination port. it is similar to MAC-XOR algorithm,so it is a kind of XOR algorithm too.and the third is based on tcp stream,but it analyses the traffic state ,The implemetation of the algorithm is given in the paper. The test results show that the algorithm has better capability of load balance as well as higher server throughgput and server availability.