An efficient packet processing protocol based on exchanging messages between switches and controller in OpenFlow networks

In OpenFlow system, there are Switches and a Controller which are communicated by OpenFlow protocol. In the beginning, a Controller receives the information from all Switches in the network and based on the received information, a Controller can build the network topology. Afterwards, Switches receive FlowTable from the Controller to operate properly based on the FlowTable. Once receiving the packets, a Switch can handle them based on the FlowTable but if a Switch receives a packet whose process is not defined in FlowTable, then the Switch transmits the packet to the Controller. After receiving it, based on the packet information, the Controller updates and then sends updated FlowTable information to the Switch. However, the numerous number of receiving packets whose process specifications are not in the FlowTable can generate a large amount of traffic load and it can also cause to degrade the network performance such as transmission delay and throughput. In this paper, we propose an efficient protocol which can effectively handle the FlowTable and the packets when the Controller receives the packets whose process specifications are not in the FlowTable. In our proposed protocol, the Controller knows the entire network topology as well as the states of Switches. The Controller select Switches to efficiently forward packets, based on the packet information. The selection of the Switches is determined by the two factors which are the shortest path and counter value which represents the number of packets. Based on these, flow-entry is generated, Switches which have to forward packets can be selected, and the generated flow-entry is transmitted to the Switches involved in forwarding the packets. Our proposed protocol can provide reducing the number of forwarding the packet and message exchanges. Thus, this makes it possible to fast transmission of the packets and to reduce the network traffic load. To demonstrate the practical efficiency and validity of the proposed me- hod, the simulation between the controller and switch are conducted and the experimental results are compared with the standard model.