Research On Multi-constrained Routing And Consistent Updates For Flow Table In SDN

With the rapid growth of network data and the diversification of business types,the "best effort" service provided by the Internet cannot guarantee the QoS of network transmission.However,traditional networks do not have a global network view;require hop-by-hop routing decision,and have limited node QoS control capabilities,Which make it difficult to solve multi-constrained routing problems.SDN is a new network architecture which decouples the forwarding plane from the control plane,has an entire network view and the centralized routing calculation.SDN provides a new platform for solving the multi-constrained routing,problem.Based on the characteristics of SDN architecture and the advantages of the bionic.multi-constraint routing algorithm,this paper proposes a multi-constraint routing algorithm CCBA based on the imprpved BA.CCBA applies BA to the multi-constrained routing problem to search for the optimal path in the network.To improve the convergence speed of the BA,CCBA introduces a chaotic operator to initialize the population,increasing the diversity of the population and improving the search efficiency in the early stage-of the algorithm.In order to avoid easily falling into local optimum,this algorithm introduces the adaptive Cauchy mutation operator,so that the algorithm has the ability to jump out of the local optimum.The experimental results show that this algorithm has better optimization ability than comparison algorithms.It is an efficient new multi-constrained routing algorithm.In SDN.,due to the link delay and the update delay of the switch,it is difficult to ensure the consistency of the control logic during the flow table update process.This may causes loops and black holes.Aiming at the requirement of consistency update,and taking advantage of determined order based update,this paper proposes a flow table consistent update algorithm based on layering update.This algorithm divides the update process into three layers,F irstly update all newly added nodes to avoid black holes.Secondly,traverse to find all nodes that can be updated without loops.Finally,the nodes that meet two loop-free update conditions are.updated in multiple rounds.The experimental results show that this algorithm has a shorter update time than the comparison algorithm,and can achieve faster consistent update of the flow table.