Deployment And Optimization Of Multi-domain Paths

Software Defined Networking(SDN)is a new network paradigm proposed in recent years.It uses a control plane and forwarding plane separation architecture,and separates two functional modules of data forwarding and routing control in traditional network equipment.The equipment of switching data can be more focused on data forwarding and improve forwarding efficiency.Centralized controller managements and configures a variety of network equipment by a standardized south interface.At the same time,the controller abstracts underlying network devices,provides a unified management view and programming interface for upper applications,and makes the network programmable.The Internet is divided into different autonomous,and the autonomous system can communicate with each other through the BGP,due to the geographical situation,different ownership and ease of maintenance and management.In order to improve the quality of network services and link utilization,the traffic engineering has been introduced.But the BGP cannot meet the needs of inter-domain traffic engineering,the idea of centralized control shows its advantages.Therefore,this paper considers SDN for inter-domain routing.Each region has its own domain controller.Each controller can learn the regional network view and handle intra-domain services.But each controller needs a global network view to make decisions for the inter-domain services.This requires co-interaction among controllers.In this paper,the interaction among multi-domain controllers is designed and implemented.The main works are as follows:(1)This paper designs a kind of light east-west peer-to-peer architecture for multi-domain controllers.It transmits and disseminates the message among controllers through the customized peer-to-peer horizontal interaction protocol.Controllers complete the synchronization and consistency of the global network state based on this protocol.(2)The system implements the dynamic join of the controller.It uses the LLDP protocol to discover inter-domain links,and transmit the information about the controller through the discovered inter-domain link.Then through the Netty controllers achieve the peer-to-peer interconnection between the adjacent controllers.The reachable area path information is transmitted among controllers.Each controller updates the data in memory according to the received information.When the business is arriving,controller selects the next hop area based on the policy of shortest across domains path.In the domain,the controller still uses the SPF policy to make a route.According to this strategy,the system deploys fast path for cross-domain business.(3)Each controller learns the underlying network topology of the region,and abstracts out a virtual network view,which is consisted of full interconnected area boundary switches.Controller statistics the information such as the bandwidth,delay,drop rate and so on of the virtual links in the virtual topology.Each controller spreads the statistical information through the neighborhood to the whole network through the horizontal interaction protocol,and finally achieves the consistency of the global network information.(4)The controller which is connected by the source switch selects an optimized path for the business based on the global network information.Each controller in the optimized path passes forward the path information.The last controller which is belonged to the last area starts to deploy flow items to the switches in this area.Controller passes backward success message through the optimized path.Then the next area controller starts to deploy flow items to the switches after it received the success message.Finally,the traffic migration is completed through the fast path to the optimized path.