Research On Virtual Machine Migration Strategies For Virtual Network Survivability

As the multi-provider nature of the Internet becomes increasingly apparent,simply updating the existing Internet structure or deploying new network technologies is difficult to reach a consensus among many competing providers.Network virtualization has been regarded as a key to solve the ossification of the Internet.It virtualizes physical computing resource,storage resources and bandwidth resources and adds them to virtual resource pool for efficient and flexible management,so as to provide users with leasable resource services according to their needs.Network virtualization enables multiple virtual networks to coexist in one or more physical networks and share physical resources.Virtual nodes generally exist in the form of virtual machines,many virtual machines are interconnected through virtual links,which makes up virtual networks,and failures of any physical network component will result in the destruction of the corresponding virtual network.In order to deal with the serious threat and destruction of virtual network caused by large-scale disasters,this thesis proposed two virtual machine evacuation schemes for different disaster scenarios.Aiming at the serious threat to physical nodes caused by large-scale disasters,this thesis proposed a virtual machine effective evacuation scheme based on disaster warning time.The proposed scheme reconfigures the threatened virtual networks and evacuates related virtual nodes according to virtual machine data amount,virtual machine downtime and the disaster warning time.The proposed scheme adopts the post-copy migration method to allocate the optimal evacuation route and initial bandwidth for the virtual machine to be evacuated under the principle of migration traffic balance,and dynamically adjust the bandwidth on the evacuation path according to the network resource situation.The simulation results show that the proposed scheme makes full use of physical bandwidth resource in disaster warning time,improves the virtual machine evacuation completion ratio,and enhance the survivability of corresponding virtual networks.Under disaster risk model,to solve the problem of decreasing reliability of virtual machines within disaster area,this thesis proposed a dual virtual machine rapid evacuation scheme.The proposed scheme first determines the basic evacuation bandwidth of the virtual machine to be evacuated through preliminary simulation,and then dynamically adjusts the evacuation bandwidth for the virtual machine according to the expected completion time of the corresponding virtual network.,and preferentially adopts the parallel migration strategy which allows to simultaneously transport the data of multiple virtual machines in one physical link,which helps to fully utilize the physical network bandwidth resources.The simulation results show that the proposed scheme effectively reduce both total evacuation time and mean evacuation time for all of threatened virtual networks,so as to reduce the probability of virtual components failure in disaster area.