Research On Software Defined Packet Transport Network Interworking Mechanism

With the rapid development of 4G network and mobile Internet, the existing PTN(Packet Transport Network) network has become increasingly difficult to meet the load of diverse services. Existing voice, video and telephone services make PTN networks need to be able to carry large-capacity, low-latency data flow. In 2009, Prof.Nick McKeown from Stanford University put forward the SDN(Software Defined Network) concept. SDN separates the data plane and the control plane from each other in the network. It is a kind of hierarchical decoupling idea, which makes the network level clearer. In the existing PTN network, the operator tries to use the SDN idea in the PTN network and combines the centralized intelligent control of SDN with PTN's efficient multi-service transmission capability for data optimization,carrier-class high reliability and end-to-end QoS guarantee obtained a new network architecture SPTN (?????????).Currently, the enterprise network uses routers for networking, and the intermediate network is a layer-2 network composed of PTN devices. Therefore,SPTN networks must be used to solve the cross-layer interworking problem of service flows. In addition, because the development of SPTN network is still at the preliminary stage, many of the traditional network equipment cannot directly compatible with the relevant protocol of SDN, so SPTN network has more advantages in flexibility and controllability compared with traditional network, but because SPTN network The SPTN network is not compatible with the traditional network, and the SPTN network is still a long way to replace the traditional network. Operators will face the long-term coexistence of traditional network and SPTN network scenarios,and how to solve the SPTN network and traditional network traffic interoperability has become an urgent problem to be solved.In this paper, a scheme to solve the interworking between SPTN services in the two-level and three-layer domains and the interworking between SPTN and traditional network services is presented. The feasibility of the scheme is verified through the experiments. The main innovations include the following:(1) The software defines the Layer2-Layer3 service interworking mechanism for the packet transport network. Through the cooperative control between the SPTN controllers, the controller matches the corresponding fields according to the service type, and modifies the MAC address of the packet through the multi-level flow table configuration.(2) The multi-domain cross-layer service QoS coordinated control of the software defined packet transport network. By setting queues on the switch and implementing the task ID for each service, the controller implements the end-to-end QoS control.(3) ARP-based BGP interoperability between software defined packet transport network and IP network. By setting up an ARP proxy, a channel is created between the SPTN controller and the external router so that the SPTN controller can communicate with the external router through BGP packets.