# Software-Defined Vehicular Cloud Networks: Architecture, Applications and Virtual Machine Migration
## 4 Migration Management of VM over SDVC
### Review of the State-of-the-Art of VM Migration Techniques over SDVC  
2.1 Overview of Architectures and Technologies Integrated with SDN and VM Migration Approach in SDVC  
SDVC architectures integrate fog/edge computing to keep data and processing services as close as possible to the vehicular users but slight VM migration strategies, as presented in Table 2. In [9], a latency performance evaluation was discussed for processing latency sensitive services using the construction model of the software-defined cloud/fog network graph model. Furthermore, edge computing approach for delivering traffic content query requested by vehicles was proposed in [45]. The approach in [45] enabled vehicles to communicate with neighboring ones through vehicle-level caching technique to minimize the network latency. Automation of traffic, improvement on disseminating driver and pedestrian safety messages, and monitoring of traffic violations are implemented through an intelligent transport system based on MEC and SDN technologies [46]. The architecture improves routing data. Furthermore, offloading algorithms achieve better packet delivery time and packet loss. The authors of [47] proposed the conceptual principles that integrate the fog/cloud network to improve user experiences and reliable vehicular communications in order to support vehicular applications with restricting QoS/QoE requirements. Cooperative driving services are enabled by architecture framework based on SDN, NFV, and MEC to support V2X network slices. In [53], distributed pseudonym pools are managed and scheduled \begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**SDVN Proposal and Its Computing Resources Architecture** & **Year to VM Migration** & **Simulation Tools** & **Use Cases** \\ \hline
[21], central cloud & 2017 & none & not specified & update softwares on vehicles \\ \hline
[48], Fog computing & 2017 & none & not specified & geographic placement of the SDN controllers \\ \hline
[36], central cloud & 2018 & none & \
\begin{tabular}{} \end{tabular} &
\begin{tabular}{} \end{tabular} & QoS and routing applications \\ \hline
[49], central cloud & 2016 & \begin{tabular}{} \end{tabular} & \begin{tabular}{} \end{tabular} & \
\begin{tabular}{} \end{tabular} &
\begin{tabular}{} \end{tabular} \\ \hline
[50], RSU cloud & 2015 & \begin{tabular}{} \end{tabular} & \begin{tabular}{} \end{tabular} & \
\begin{tabular}{} \end{tabular} &
\begin{tabular}{} \end{tabular} \\ \hline
[51], multi-access edge computing & 2019 & none & not specified & \
\begin{tabular}{} \end{tabular} &
\begin{tabular}{} \end{tabular} \\ \hline
[52], multi-access edge computing & 2018 & none & Minenet-WiFi & \
\begin{tabular}{} \end{tabular} &
\begin{tabular}{} \end{tabular} \\ \hline
[53], vehicular cloud & 2016 & none & none & not specified \\ \hline
[47], fog computing & 2018 & none & OMNeT++, SUMO [55] & content distribution \\ \hline
[46], edge computing & 2018 & none & not specified & content dissemination \\ \hline
[45], edge computing & 2018 & none & Mininet-WiFi, SUMO & content distribution \\ \hline
[9], edge computing & 2016 & none & not specified & content dissemination \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Review of the state-of-the-art of VM migration techniques over SDVC. through software-defined pseudonym system. The SDN concept mitigated the system overheads cost by proposing two-side matching theory that solves the matching problem among the pseudonym pools. In the works by [PERSON] et al. [52], V2X network slices are implemented through the use of softwarization technologies such as SDN, NFV, and MEC. The aim of the V2X network slice enables the cooperative driving services under intra- and inter-operator mobility. The problem of mobility is addressed by the use of V2X network slices. It is realistic to improve the packet delivery rate of safety messages through VM migration services. In addition, the SDN controller selects the best MEC on which a current cooperative service would resume to the next MEC server.