New Algorithm Based On Multi-domain Architecture SDN And Loop-free Consistent Updates For Openflow Flow Table

The development of SDN(Software Defined Network) makes it possible for a more flexible management of the network, and also provide more opportunities for innovation of network routing algorithms. With the increasing deployment of SDN in large-scale network and WAN, single-controller deployment is under great pressure, and distributed multi-controller provide an alternative for the control plane scalability. In large-scale SDN with many nodes, multi-domain architecture becomes a trend.For cross-domain network communication, we need information both from intra-domain controller and inter-domain controller, which means that we need a combination of distributed network architecture and a centralized controller. In this way we can reduce the complexity of large-scale network routing algorithm, and adopt different policies between intra-domain and inter-domain. In this paper, we propose a novel routing algorithm, which will find a path in the multi-domain architecture SDN with a limited delay and a relatively small cost. The complexity of the algorithm will be polynomial.In SDN, although there is a logically-centralized controller, SDN is still a distributed system. As the delay between controllers and switches is inevitable, it is difficult to ensure consistency of routing table updates,especially when it comes to traffic surge or WAN. To solve this problem,this paper studies related techniques on flow table update consistency, and analysis the advantage and disadvantages of the existing schemes. Then we design a new model with loop-free consistency. With this model we propose a novel algorithm based on multi-directional update strategy. At last, we do the simulation. Compared with existing scheme, our algorithm significantly reduces the length of dependency chain and update delay, and the result is comparable with the optimal scheme.