关键词: 软件定义网络, 带内通信, 多控制器容错, 交换机簇划分, 交换机重托管

Abstract: SDN proposes to decouple the control plane from the forwarding plane and provide programmability of the control plane to meet new network requirements. Centralized controllers have brought many conveniences along with a lot of new challenges. Especially, the controller’s single point of failure is a problem which cannot be ignored. This paper studies the fault tolerance and fast recovery of multi-controller mechanism under in-band control scenarios. Traditional multi-controller fault-tolerant scheme mainly focuses on hierarchical architectures, which is, to some extent, a great waste of controller resources. Instead, this paper proposes a planar controller architecture, as controllers connect end to end and form a ring structure, and adjacent controllers are responsible to monitor each other to detect controller failures. Once failure occurs, the switch cluster partition algorithm and switch re-hosting algorithm will be used to accomplish fast recovery of the network through transferring switches under faulty domain to the rest of controllers which are still working normally. There is a possibility that the total remaining capacity of the normally working controllers is less than the number of switches under the faulty domain. In order to cope with this situation, the paper proposes to insert controllers dynamically.

Key words: Software Defined Network（SDN）, in-band control, multi-controller fault tolerance, switch cluster partitioning, switch re-hosting