多单元散列表与TCAM结合的OpenFlow流表查找方法

摘要

在OpenFlow网络中，交换机通过标准化的接口接受基于流的规则，执行基于流的报文处理。流表的查找是OpenFlow交换机的核心功能，TCAM以其优异的性能广泛用于OpenFlow流表的查找，然而基于TCAM的OpenFlow流表查找具有较高的成本与能耗。为了降低流表查找的成本与能耗，提出了多单元散列表与TCAM结合的OpenFlow流表存储与查找的方法。通过理论分析与仿真测试，给出了查找结构成本优化后的散列表、TCAM的容量配置；在该配置下，Hash-TCAM流表查找结构比单纯使用TCAM的方案节约90%以上的成本，有效降低了能耗，同时保持了相近的查找性能。%In OpenFlow networks, switches accept flow rules through standardized interfaces, and perform flow-based packet processing. To facilitate the lookup of flow tables, TCAM has been widely used in OpenFlow switches. However, TCAM is expensive and consumes a large amount of power. A hybrid lookup scheme integrating multiple-cell Hash table with TCAM was proposed for flow table matching to simultaneously reduce the cost and power consumption of lookup structure without sacrificing the lookup performance. By theoretical analysis and extensive experiments, optimal capacity configuration of Hash table and TCAM was achieved with the optimized cost of flow table lookup. The experiment results also show that the proposed lookup scheme can save over 90% cost and the power consumption of flow table matching can be reduced significantly compared with the pure TCAM scheme while keeping the similar lookup performance.