# Software-Defined Vehicular Cloud Networks: Architecture, Applications and Virtual Machine Migration
## 4 Migration Management of VM over SDVC
### SDN Controller Assistance for VM Migration over SDVC  
The MEC cloud consists of the control layer and the forwarding layer. The assistance for VM migration is controlled through the control layer, which includes several SDN controllers. The SDN controller holds the management of the global network. It requires getting network status from SDN communication and active VM controller. The SDN communication infrastructure controller is in charge of adjacent MEC micro-data center and particularly manage the connectivity of heterogeneous radio access when the VM service resumes the adjacent MEC micro-data center. The migration of VM-overlay and VM-base is managed by the active VM controller as long as the vehicle moves from the current MEC micro-data center hosting the cloud-based vehicular services. The active VM controller manages the flow tables of MEC radio access and forwarding devices at the forwarding layer. The MEC micro-data center supports closest vehicles (V2X enabled UE). As the coverage of MEC micro-data center would experience short disconnection in case the vehicle moves far of the MEC radio access coverage. In [4], four scenarios of VM service migration on cloud-based vehicular network have been proposed. Based on the four VM migration case studies (Inter-Cloudlet, Intra-Cloudlet, Across Roadside-Vehicular Cloud and Across Roadside-Central Cloud) of [PERSON] et al. [4] and the concept that routing policies of RSU and vehicles are managed from the control plane, this paper discusses the VM migration of active VM controller. The inter-MEC migration service concerns the VM migration from one MEC micro-data center to its immediate next MEC micro-data center when the two MEC computing resources are in different radio access network coverage. In this case, the active VM controller of MEC micro-data center-1 will not be migrated because the dedicated VM migrates to the next MEC micro-data center. Therefore, the active VM controller of MEC micro-data center would include routing paths to new packets from central cloud service. Then, the forwarding device of the radio access would take actions regarding \begin{table}
\begin{tabular}{l l l l l l l l} \hline \hline  & \multicolumn{3}{c}{**Relevant SDN Controllers Assistance**} & \multicolumn{3}{c}{**Resource Sharing**} \\ \hline \multirow{3}{*}{**Potential Application**} & **SDN** & **SDN** & **Communication** & **Active** & \multirow{3}{*}{**Computation**} & \multirow{3}{*}{**Storage**} & **Bandwidth** & **Latency (ms)** \\  & **OpenFlow** & **Inrastructure** & & & & & \\  & **Controller** & & & & & & \\ \hline Real-time traffic condition & & & & & & & \\ analysis and broadcast & & & & & & & \\ \hline Real-time car navigation & & & & & & & \\ \hline Video surveillance & & & & & & & 120–200 [42] \\ \hline LBS commercial & & & & & & & \\ advertisement & & & & & & & \\ \hline Mobile Social networking & & & & & & & \\ \hline In-vehicle multimedia & & & & & & & \\ entertainment & & & & & & \\ \hline Intervehicle video and & & & & & & & \\ audio communications & & & & & & & \\ \hline Remote Vehicle & & & & & & & \\ Diagnostics & & & & & & & \\ \hline location-based services & & & & & & & \\ recommendation based on & & & & & & \\ personalized and precise & & & & & & & \\ service [44] & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Applications based vehicular network over SDVC. the type of VM migration pre-defined in the in-coming packets field of flow entries. This scenario is shown on Figure 7a. Figure 7b shows the intra-MEC VM migration case. The adjacent MEC micro-data enter connects to the same radio access network. In this case, the active VM controller would migrate at the same time with VM-operating system/application. The active VM controller should continue to manage forwarding devices in the two MEC micro-data center since they share the same radio access network. In the case of across MEC micro-data center computing, vehicles establish an ad-hoc network. In this case, the access radio coverage is the same for the two MEC micro-data center.