Research Of Reordering And Load Balancing In Multi-Path

Multi-path transmission, using several paths between the diverging point and the converging point, is used to transmit packet. Compare to the traditional single path transmission, multi-path transmission can make the best of network resources, reduce the congestion, improve the transmission reliability and security, etc. Therefore, it is a research hotspot in network field. Because of the delay deference between the parallel paths, the packets reaching the converging point will be out of order while they are sent orderly at the diverging point; in addition, multi-path transmission will present some problems about load balancing among the paths; furthermore, reordering and unbalanced load have adverse effects upon transmission rate, quality of service, the utilization rate of resources, etc. So, it is be of great significance to do some research on traffic splitting algorithm, which can guarantee the order of packets and realize the load balancing.At present, the issue of researching on traffic splitting algorithm mainly focuses on one of the two points, guaranteeing the order of packets and load balancing, although little of them focus on them together, the performance of load balancing is not very good because of the coarse grain of traffic splitting. This paper first analyzes the adverse effects upon the network performance resulted from out of order, and then introduces several traffic splitting algorithms and analyzes their merits and flaws. On this basis, this paper proposes a new traffic splitting algorithm, which can achieve good load balancing by splitting traffic into flow slices as fine-grained as possible. The new algorithm is mainly carried out by constructing a nonius which can be used as a baseline of path latency. The nonius, which is used to guarantee the order of packets, mainly depends on two parameters, the path latency and the interval between two successive packets. The nonius can slide dynamically because of different path or the different interval between two successive packets. By sliding dynamically, the packet can be transmitted among as many paths as possible; as a result, the load balancing can be achieved. Through trace driven simulation of the traffic splitting algorithm based on nonius and other existed traffic splitting algorithms, the simulation results show that the proposed algorithm gains a prominent improvement in load balancing over previous algorithms, while without reordering is guaranteed.