针对无线控制环境的OpenFlow流表申请优化机制

Optimized Flow Table Application Mechanism for Wireless Control Environment

在无线控制环境下,受限于控制通道的带宽和时延,OpenFlow交换机通过Packet-In消息申请流表的过程耗时较长,这个时段内交换机可能收到同一条流的大量后续报文,并分别产生与首包报文完全相同的Packet-In消息发往控制器,明显浪费网络资源。同时,针对每条流独立发送一个Packet-In报文的方式容易导致控制通道负载以小包为主、包头开销占比过大、网络资源利用率不高的问题。因此,针对无线控制条件下报文粒度Packet-In消息触发和离散化Packet-In消息发送机制存在的问题,提出了一种基于流粒度实现Packet-In消息触发和Packet-In消息聚合发送的方案,并通过仿真试验,验证了方案的效果。

In the wireless control environments,limited by the bandwidth and latency of the control channel,the OpenFlow switch takes a long time to apply for a flow table through Packet-In messages,and the switch may receive a large number of subsequent messages of the same flow during this time and generate an identical Packet-In message for each of the subsequent messages,which obviously wastes network resources.Meanwhile,sending a Packet-In message independently for each flow may cause the problem that the load of the control channel is dominated by small packets,the overhead of the packet header accounts for too large a proportion,and the utilization of network resources is not high.Therefore,to address the problems of granularity Packet-In message triggering and discrete Packet-In message sending mechanism under wireless control conditions,this paper proposes a scheme based on flow granularity to realize Packet-In message triggering and Packet-In message aggregation sending,and verifies the effectiveness of the scheme through simulation experiments.