Load Balancing Algorithm Using Flow Chopping to Avoid Packet Reordering

Load balancing is an effective technique that keep network from congestion when link is over load or link failures occur. The performance of balancing system is determined by granularity of load splitting. The finer the granularity is, the better performance can be attained. But splitting schemes must make a tradeoff between slicing granularity and packets reordering. Packet-level granularity can obtain accurate load assignment, but it will make a lot of reordering packets in the same TCP flow. While flow-level granularity will not cause packet reordering, but in this mechanism each path get inaccurate load assignment compared with it's desired load sharing. In this paper, we show that one can split a flow into multi path without causing packet reordering, by chopping the flow into several segments using the time slot between consecutive packets of the same flow. A new traffic splitting algorithm which is named as Flow Chopped Load Balancing algorithm (FCLB) is proposed based on this novel idea. We compared the performance of FCLB with one packet-level scheme round robin and one flow-level scheme static hashing using a combination of synthetical analysis and trace-driven simulation. The results show that FCLB can attain accurate load assignment without reordering packets.