Research Of Controller Structure And Service Function Chaining In Software Defined Networking

Distributed controllers and two-layer controller structure have been proposed for Software Defined Networking(SDN)to address the issues of scalability and reliability that a centralized controller suffers from.Since SDN is becoming more and more popular,it is urgent to solve the controller placement problem but the recent researches are confined to add constraint parameters.This thesis researched the controller placement problem in both structure and constraints,and presented a new two-layer distributed controller structure Cacc with the features of overlap management and dynamic management.Cacc has advantages of load balancing and manageability.Furthermore,this thesis carried out performance modeling of controller topologies and proposed a new placement problem for Cacc:Capacitated Multi-Controller Placement Problem(CMCPP),in which one local controller is assigned to two or more root controllers with capacity limitation to achieve an high reliability.Both of the analysis and experiment results verified the reliability advantages of CMCPP.SFC(Service Function Chaining)was proposed for increasing the speed on which services are deployed and reducing operational costs.In SFC,service functions connected in a certain order to meet business needs.In current research of SFC,the modeling of the service functions is far from enough,which is a impediment to the realization of service chain.Combining the popular OpenFlow Table and ForCES(Forwarding and Control Element Separation)LFB(Logical Function Block)technique,this thesis designed a generic SFB(Service Function Block)library,including the delineation of SFB class,the functional elements in each SFB class,and the process to built SFC using this SFB library.By applying a specific example,the thesis describes how to use the SFB library in detail,which preliminarily verified the feasibility of SFB library and which is also a guidance for the implementation of SFC application in SDN.