Power-efficient Data Center Networks (DCNs) have been proposed to save power of DCNs using OpenFlow. In these DCNs, the OpenFlow controller adaptively turns on/off links and OpenFlow switches to form a minimum-power subnet that satisfies the traffic demand. As the subnet changes, flows are dynamically routed and rerouted to the routes composed of active switches and links. However, existing flow scheduling schemes could cause undesired results: (1) power inefficiency: due to unbalanced traffic allocation on active routes, extra switches and links may be activated to cater to bursty traffic surges on congested routes, and (2) Quality of Service (QoS) fluctuation: because of the limited flow entry processing ability, switches may not be able to timely install/delete/update flow entries to properly route/reroute flows. In this paper, we propose AggreFlow, a dynamic flow scheduling scheme that achieves power efficiency and QoS improvement using three techniques: Flow-set Routing , Lazy Rerouting , and Adaptive Rerouting . Flow-set Routing achieves load balancing with a small number of flow entry operations by routing flows in a coarse-grained flow-set fashion. Lazy Rerouting spreads rerouting operations over a relatively long period of time, reducing the burstiness of entry operation on switches. Adaptive Rerouting selectively reroutes flow-sets to maintain load balancing. We built an NS3 based fat-tree network simulation platform to evaluate AggreFlow’s performance. The simulation results show that AggreFlow reduces power consumption by about 18%, yet achieving load balancing and improved QoS (low packet loss rate and reducing the number of processing entries for flow scheduling by 98%), compared with baseline schemes.

中文翻译：

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AggreFlow：在数据中心网络中实现电源效率，负载平衡和服务质量

已经提出了高能效的数据中心网络（DCN），以使用OpenFlow节省DCN的功率。在这些DCN中，OpenFlow控制器自适应地打开/关闭链路和OpenFlow开关，以形成满足流量需求的最小功率子网。随着子网的变化，流会动态路由，然后重新路由到由活动交换机和链路组成的路由。但是，现有的流量调度方案可能会导致不希望的结果：（1）电源效率低下：由于活动路由上的流量分配不平衡，可能会激活额外的交换机和链路来应对拥塞路由上的突发流量激增，以及（2）服务质量（QoS）波动：由于流条目处理能力有限，交换机可能无法及时安装/删除/更新流条目以正确路由/重新路由流。在本文中，流集路由 ， 延迟重新路由 ， 和 自适应重路由 。流集路由通过以粗粒度流集方式路由流来实现少量流进入操作的负载平衡。惰性重路由可以在较长的时间内扩展重路由操作，从而减少了交换机上入口操作的突发性。自适应重路由选择性地重路由流集以保持负载平衡。我们构建了一个基于NS3的胖树网络仿真平台来评估AggreFlow的性能。仿真结果表明，与基线方案相比，AggreFlow降低了约18％的功耗，但实现了负载平衡并提高了QoS（低丢包率，流调度的处理条目数量减少了98％）。