Research On Interconnection Mechanism For SDP Subnet And IP Subnet In Autonomous System

Software defined networking (SDN) is considered to be the trend of future network. But the SDN network and the traditional network can’t communicate directly at the moment because of the huge difference between their architectures. The interconnection mechanism for SDN network and traditional IP network has been the focus in academia, but the current solution can’t be used in every condition. To solve this problem, this paper proposes an architecture named IMISA which is based on the OSPF protocol. In the Autonomous System with both SDN subnet (based on OpenFlow) and IP subnet, a translator is added to the border of the SDN network. On one hand, the translator gets the information about traditional network from the area border router through OSPF protocol and then sends it to the SDN controller. On the other hand, the translator gets the information about SDN network from the SDN controller and then sends it to the area border router through the OSPF protocol.As a result, the networks can communicate with each other. When the IP subnet or the SDN subnet changes, the peer subnet should realize this and modify its forwarding rules in time.In this paper, the characters of each popular SDN controller are analyzed so that we can find out the ideal controller. The architecture and mechanism of Ryu are also studied, and in particular, the REST APIs of Ryu are encapsulated so that they can be used more conveniently. An application is implemented to calculate the shortest path using Dijkstra algorithm and then create the flow entries. A module which is used to get the SDN networks that are reachable to traditional networks by analyzing the flow entries on the border OpenFlow switch is added to Ryu. An ARP proxy module is implemented so that communications between different network segments in Layer 3 become possible. A mechanism combined with initial static configuration and dynamic management during running time is also declared in this paper to manage the network topology. What’s more, due to the dividing of function modules, this mechanism has high scalability.