Research On Slice Reconfiguration Technology For Software-Defined Network Virtualization

Network virtualization technology can solve the problem of network rigidity by allowing multiple virtual networks to share a physical network.We can use this technology to provide new network services appropriately and efficiently in a short period of time.Network virtualization can also effectively improve the utilization of network resources and avoid the disadvantages of using physical network to run a network service separately.Software-defined networking(SDN)is also a technology that enables physical networks to better deploy new services in real time.SDN technology separates network data forwarding plane and control plane,implements centralized control over network forwarding plane,and strengthens the programmable characteristics of network,which greatly improves the flexibility of network.Network virtualization and SDN technology are combined to make the network slice composed of programmable SDN network,so as to build software-defined virtual network(vSDN)for tenants,which can greatly improve the flexibility of the network.However,the network environment is dynamic,and the resource requirements of vSDN will change over time,while the requests of tenants are also constantly arriving and leaving.This will make the virtual network mapping(VNE)scheme,which was the optimal solution at the beginning,no longer applicable,so that the resource utilization of the physical network will appear unreasonable,and we can use vSDN reconfiguration(change the VNE scheme of network slice)to solve this problem.Of course,in addition to redistributing resources,failure recovery,mobile management,and so on,are also the scenarios for the vSDN to be reconfigured.But vSDN reconfiguration still has a lot of work that hasn't been studied.The optimization purpose of vSDN reconfiguration,the network scenario of vSDN reconfiguration,and the design and implementation of vSDN reconfiguration system are not perfect in terms of research scope and research depth.Therefore,this dissertation studies the slicing reconfiguration(vSDN reconfiguration)technology for software-defined network virtualization.Firstly,we broaden the research scope of vSDN reconfiguration,such as vSDN reconfiguration for the purpose of balancing flow table utilization and vSDN reconfiguration in hybrid optical/electrical datacenter network(HOE-DCN).Then we optimize the vSDN reconfiguration process from two perspectives of reducing the interruption of the stream and reducing the reconfiguration time.Finally,we design a vSDN reconfiguration system with tenant non-awareness.These research contents are of great significance for improving the vSDN reconfiguration.Specific research contents and contributions are as follows:·First,we start the whole topic from the balancing the usage of flow-table on physical switches.In the previous vSDN reconfiguration problem,no relevant work has been conducted from the perspective of balancing flow-table utilization.Therefore,in order to fill this gap,we carry out theoretical modeling and algorithm design for this problem.We first design a selection algorithm to select the appropriate virtual nodes for reconfiguration.Then we design mixed integer linear programming(MILP)to compute remapping schemes for virtual nodes and links to be reconfigured.In order to reduce the time complexity,we design the Node-first remapping algorithm(NF-R)and Link-first remapping algorithm(LF-R)to obtian nearoptimal solution.The results show that we can solve the problem of unbalanced us?age of flow-table resources well.·However,both the above schemes and the previous existing vSDN reconfiguration schemes lack the optimization of the VSDN reconfiguration process,so we separate the VSDN reconfiguration process for research.We design the parallel VSDN reconfiguration mechanism from two perspectives:minimizing the flow interrupts and reducing the reconfiguration time.Firstly,we considered using the one-stage parallel reconfiguration scheme,but the one-stage parallel vSDN reconfiguration could not be realized under the condition of limited resources,so we designed the multi-stage parallel vSDN reconfiguration scheme to carry out parallel reconfiguration of virtual nodes and virtual links in multiple batches.It can be seen from the results that the parallel reconfiguration scheme designed by us can effectively reduce the number of reconfiguration and thus reduce the complexity of reconfiguration operation.·Then,this dissertation studies vSDN reconfiguration in HOE-DCN.In this scenario,the TOR switch is connected with the optical cross connect(OXC)to form an OCS(optical circuit switching)-based network with connectivity of 1,and in the process of network reconfiguration,in addition to the configuration change of the EPS(electrical packet switching)-based network,OXC reconfiguration will also be involved.As a result,the vSDN reconfiguration in the HOE-DCN also includes the physical topology change(OXC reconfiguration).Therefore,this dissertation first designed a reconfiguration scheme to solve the imbalance of computing resources,and then designed the parallel reconfiguration scheme to optimize the reconfiguration process in the HOE-DCN.·Finally,this dissertation extends the function of network virtualization hypervisor(NVH)to realize parallel VSDN reconfiguration function without tenant aware-ness on the basis of make-before-break reconfiguration scheme.Experiments show that the system can effectively improve the flow interruption phenomenon in the reconfiguration process and reduce the reconfiguration time.