Research On Cross-Domain Routing And Resources Optimization For Middlebox In Software-Defined Networking

SDN(Software-Defined Networking) is a novel network architecture that separates the control plane from the data plane. It usually utilizes a centralized controller to manage all the switches in the network. With the expanding of network scale, both the complexity of control functions and the amount of messages exchanged between controller and switches are increasing sharply. The limited performance of a single controller and the heavy load will cause congestion in the control plane. Multiple controllers scheme have been proposed to solve this problem by dividing the network into multiple domains. However, in this architecture, cross-domain routing will involve multiple controllers which will increase control plane load.Based on the SDN center management, some schemes that leverage SDN to optimize middleboxes resources have been proposed. Middleboxes are special network devices that provide network functions(e.g.. Firewall, Proxy) with dedicated hardware. Network flows may visit different physical machines(PMs) to get complete services, and this will increase flows delay and traffic load. Consolidated middlebox which decouples middlebox from hardware enables multiple middleboxes to run in one physical machine, and makes flows get complete service in one PM. Previous works about middlebox mainly focus on the load balancing between PMs. However, the uneveness of multiple resources utilization in each PM may produce resource bottleneck due to irrational flows steering.The main research work of this article as follows:(1) Based on the source routing and pre-routing technology, we propose a cross-domain source routing scheme(CSRS) for multi-domains SDN networking. In this scheme, cross-domain flows just need to interact with controllers in the source domain and destination domain. In the intermediate domains, flows can be routed along the paths established during the pre-routing process. Thus, cross-domain flows do not burden the controllers in the intermediate domains. In this scheme, controllers just need to carry load of related business. This scheme will improve the network scalability. Finally, the simulation results verify CSRS performance.(2) Based on the architecture of SDN and Consolidated Middlebox, we present a multi-resources utilization balancing scheme to balance resources usage in each PM. In the multi-resources utilization balancing scheme, "skewness" is introduced to represent the unevenness of PM. According to the flows resources demand and status of PMs, a genetic algorithm is designed to steer flows to balance resources usage in each PM. Meanwhile, due to the constraints of delay and service functions demand, flows may be steered to the PMs with high resources utilization. PM’s resources utilization may exceed the upper bound. In this case, we define "Multi-Dimensional Resource Correlation Ratio(MDRC)" to select flows to migrate to available PMs. Finally, simulation results show scheme performance.