Research On The Online Application State Partition Migration For Distributed Controller

The expansion of network scale and the diversity of network data make the network structure more complicated. Traditional network equipments become bloated due to the consistent expansion of the bearing function, which makes the management of the whole network more difficult for network manager. The emergence of the software defined network overturns the thought that control plane couples with forwarding plane in traditional network. The control plane is separated with forwarding plane by coupling. The forwarding plane is only responsible to forward data while forwarding rules are controlled by control plane. The transparency of the underlying physical device to the upper application is achieved and the management problems of complex network are simplified.In the large and complex network data center, deploying SDN single node controller and adopting the best forwarding decision based on the entire network uses are the effective methods to realize the intelligent network management. Compared with the problems that single node controller is easy to have break down and the load is uneven, the distributed controller that centralized logically and dispersed physically can solve the shortcomings and the insufficiency of the single node controller through dynamic extension forwarding nodes. However, the new problem is also brought. Most of distributed controller architectures depend on the distributed storage, which would cause excessive rules forwarding delay. Excessive controller resource allocation is used to adopt to the sudden network peak value, which would cause a lot of resource waste and increase the deployment costs. Some research methods that partition the application status solve the problems of resource waste, but the flexible adjustment of distributed controllers is not studied completely.This thesis has completed the online migration research and design of application state partition. The online migration of application service is realized by using the application state partition migration as the core and combining controller instance management and forwarding equipment migration. There are two major benefits compared with the similar work, reducing the application storage overhead in the whole system and making the application run smoothly in the process of controller instance dynamic adjustment. The specific implementation details include:(1) Monitor and analyze the load condition of distributed controller instance and decide to increase or decrease the controller instance number according to the preset threshold value;(2) Design the related transmission protocol of migration switch and application sate partition. The migration strategy, migration protocol and controller signal designed in this thesis are used to send protocol in the whole migration process. The whole process is transparent to the top application layer and users in order to guarantee the normal operation of the network;(3) the above work is designed as SDN distributed controller application state partition migration algorithm 。 This algorithm can finish the synchronous adjustment of controller instance, forwarding equipment and application state partition in the distributed controller. This algorithm is used generally in hierarchical controller and collaborative controller to improve these controllers’ efficiency. In the end, this thesis conducted a series of experiments on the proposed work. The experimental results show that this architecture solve the load balancing problem of SDN distributed controller in the migration process and reduce the system overhead and network latency.