摘要:基于软件定义网络（software defined network，简称SDN）的数据中心流量工程，能够通过对全局视图的网络管控，动态选择路由路径，规避拥塞发生的风险.但是在制定路由策略时，经常会对数据流进行迁移，尤其是针对大流的迁移容易造成数据流丢包以及接收端数据包乱序的问题.提出了基于时隙的流片装箱算法（flowlet-binned algorithm based on timeslot，简称FLAT），通过集中控制的方式获取链路状态信息并计算出合理的数据流传输时隙值，能够避免在数据流迁移过程中的丢包以及接收端数据包乱序问题；同时，在充分利用数据中心冗余链路的前提下，实现高效和细粒度的流量均衡.通过在Mininet仿真平台中部署并与ECMP以及GFF路由机制相比较，在链路高负载情况下，丢包率分别下降了90%和80%，而吞吐量分别能够提升44%和11%，实验结果展示了FLAT的优越性能.



Abstract:Traffic engineering based on SDN (software defined network) can select routing paths dynamically in order to evade the risk of congestion through global view of network in data centers. However, the design of routing strategy often needs to change routing path during packet transmission, especially for elephant flows, which may commonly result in the problem of packet losses and out-of-order at receivers. To address the problem, an algorithm named "flowlet-binned algorithm based on timeslot (FLAT)" is proposed. FLAT is able to gather the information of link state and calculate the proper transmission timeslot under centralized control, which can solve the problem of packet losses and out-of-order. In the meantime, traffic balance with high efficiency and fine granularity can be achieved under considerable use of the redundant links in data centers. Finally, simulation results show better performance of FLAT in Mininet platform compared with ECMP and GFF routing strategies with the packet loss rate respectively falling by 90% and 80%, and the throughput increasing by 44% and 11%, especially under the condition of high load of links.



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