基于软件定义网络的分层式控制器负载均衡机制

Load balancing mechanism for hierarchical controllers based on software defined network

针对软件定义网络(SDN)多控制器负载均衡过程中控制器之间通信开销大以及控制器吞吐量低等问题,提出一种分层式控制器负载均衡机制。基于分层式架构,通过超级控制器与域控制器协作完成负载均衡,并采用预定义负载阈值以减少域控制器与超级控制器之间的消息交换开销;同时,该机制可以有效选择出过载最重的域控制器,并从该过载域控制器所控制的交换机中选取多个符合迁移标准的交换机,将其同时分别迁移到多个综合性能高的域控制器上,从而解决多控制器间负载不均衡问题。实验结果表明,与层次式SDN控制器协同负载均衡方案(COLBAS)以及用于控制器负载均衡的动态和自适应算法(DALB)相比,所提机制系统的消息数量降低了约79个百分点,且该系统的吞吐量分别比DALB、COLBAS分别提高了约8.57%、52.01%。所提机制能够有效降低通信开销,并提高系统吞吐量,有更好的负载均衡效果。

Aiming at the problems that the communication overhead between controllers is large and the controller throughput is low during the load balancing process of multi-controller in Software Defined Network （SDN）, a hierarchical controller load lmlancing mechanism was proposed. Based on the hierarchical architecture, the load balancing was completed through the collaboration of super controller and domain controller, and the predefined load threshold was used to reduce the message exchange overhead between domain controller and super controller. At the same time, the most overloaded domain controller was effectively selected. A plurality of switches conforming to the migration standard were selected from the switches controlled by the most overload domain controller. Simultaneously the selected switches were respectively migrated to a plurality of domain controllers with high overall performance, which solving the problem of load imbalance among multiple controllers. The experimental results showed that, compared with the COoperative Load BAlancing Scheme for hierarchical SDN controllers （COLBAS） and the Dynamic and Adaptive algorithm for controller Load Balancing （DALB）, the number of messages in the proposed mechanism system was reduced by about 79 percentage points, and the throughput of the proposed system was about 8.57% higher than DALB and 52.01% higher than COLBAS. The proposed mechanism can effectively reduce the communication overhead and improve the system throughput to achieve a better load balancing effect.