Software-Defined Networking (SDN) has obtained a lot of attention in the last decade and has played a significant role in the development of next-generation networks (NGN). IP networks can also benefit from the SDN evolution to fulfill the data traffic booming. However, the transition of the traditional networking model to SDN architectures poses scalability issues due to the possible flow entry explosion in SDN switches. The limited size of flow-table of SDN switches is not sufficient to handle thousands upon thousands of flows in a large-scale IP network. On the other hand, the interleaved allocation of non-contiguous IP addresses also leads to inefficient routing aggregation and reduces the feasibility of the serious implementation of SDN severely. Therefore, we propose an aggressive flow aggregation scheme—Destination Address Translation and Source-Port Translation on Demand (DATSPToD), which is based on the modified address and port rewriting. DATSPToD enables the aggregation of flow entries in SDNs by translating the destination addresses of multiple same-destination flows with different-source into one flow entry, thus significantly reducing the volume of flow-table occupancy of core-layer SDN switches, even in freely scattered IP address space environments. Simulation results show that DATSPToD outperforms non-aggregation and both wildcard aggregation schemes for a significant reduction of the flow-table occupancy under varied traffic patterns and topologies, especially in large-scale SDNs such as the Internet during the SDN migration period. Compared to the competed schemes under varied traffic patterns and topologies, the simulation results of the DATSPToD could significantly reduce flow-table occupancies by at least1 13%, and by up to 52%. The table-miss rates could be reduced from 11% to 66%.

在过去的十年中，软件定义网络（SDN）受到了广泛关注，并在下一代网络（NGN）的开发中发挥了重要作用。IP网络也可以从SDN演进中受益，以实现数据流量的快速增长。但是，由于SDN交换机中可能出现流条目激增，传统网络模型向SDN架构的过渡会带来可伸缩性问题。SDN交换机流表的大小有限，不足以处理大规模IP网络中成千上万的流。另一方面，非连续IP地址的交错分配也会导致路由聚合效率低下，严重降低严重实施SDN的可行性。因此，我们提出了一种积极的流聚合方案-目标地址转换和按需源端口转换（DATSPToD），该方案基于修改后的地址和端口重写。DATSPToD通过将多个具有不同源的相同目标流的目标地址转换为一个流条目来实现SDN中流条目的聚合，从而即使在自由分散的情况下，也大大减少了核心层SDN交换机的流表占用量IP地址空间环境。仿真结果表明，DATSPToD优于非聚合和两种通配符聚合方案，在各种流量模式和拓扑下，特别是在SDN迁移期间的Internet等大型SDN中，流表占用率均显着降低。与各种流量模式和拓扑下的竞争方案相比，DATSPToD的仿真结果可以显着减少流表占用率至少1 13％，最多减少52％。桌漏率可以从11％降低到66％。