# Development of Intelligent Core Network for Tactile Internet and Future Smart Systems
## 3 System Structure
As the system can define and implement new rules through SDN switches and Middleboxes and
5- the system provides higher scalability than traditional packet core networks. This is because the SDNC takes into account the control process only and not involved in data flow. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Controller** & **Implementation Language** & **Developer** & **Year of Release** & & **Review** \\ \hline NOX [39] & C++/Python & Nictra & 2008 & - & The first SDN controller. - & considered as network operating system than being a controller. \\ \hline \multirow{4}{*}{Maestro [40]} & \multirow{4}{*}{Java} & \multirow{4}{*}{Rice University} & \multirow{4}{*}{2011} & - & Allows applications to access and modify the network state. - & \multirow{4}{*}{The first SDN controller. - } & \multirow{4}{*}{The first SDN controller. - } \\  & & & & - & considered as network operating system than being a controller. \\ \hline \multirow{4}{*}{Maestro [40]} & \multirow{4}{*}{Java} & \multirow{4}{*}{Rice University} & \multirow{4}{*}{2011} & - & Allows applications to access and modify the network state. - & \multirow{4}{*}{The first SDN controller. - } \\  & & & - & considered as network operating system than being a controller. - & \multirow{4}{*}{The first SDN controller. - } \\  & & & & - & considered as network operating system than being a controller. - \\ \hline \multirow{2}{*}{POX [41]} & \multirow{2}{*}{Python} & \multirow{2}{*}{Nictra} & \multirow{2}{*}{2013} & - & Allows applications to access and modify the network state. - \\  & & & & - & considered as network operating system than being a controller. - \\  & & & & - & Multi-thread platform. - \\  & & & & - & Portable and scalable. - \\ \hline \multirow{2}{*}{POX [41]} & \multirow{2}{*}{Python} & \multirow{2}{*}{Nictra} & \multirow{2}{*}{2013} & - & become more common than the old NOX. - \\  & & & & - & Modern controller that enables rapid development and prototyping. - \\ \hline \multirow{2}{*}{Beacon [42]} & \multirow{2}{*}{Java} & \multirow{2}{*}{Stanford University} & \multirow{2}{*}{2013} & - & Dynamic and cross-platform. - \\  & & & & - & used to increase productivity of developers. - \\  & & & & - & enables the start and stop of applications and introducing newer ones. - \\ \hline \multirow{2}{*}{Floodlight [43]} & \multirow{2}{*}{Java} & \multirow{2}{*}{Big Switch Networks} & \multirow{2}{*}{2013} & - & One of the leading SDN controllers. - & \multirow{2}{*}{Hybrid controller that can support both OpenFlow and non - - - OpenFlow networks. - } \\  & & & & - & High performance multi-thread controller. - \\ \hline \multirow{2}{*}{OpenDaylight [44]} & \multirow{2}{*}{Java} & \multirow{2}{*}{OpenDaylight Foundation} & \multirow{2}{*}{2013} & - & efficient for any size networks. - \\  & & & & - & provides various commercial use cases. - \\  & & & & - & Main concern is the network programmability. - \\ \hline \multirow{2}{*}{IRIS [45]} & \multirow{2}{*}{Java} & \multirow{2}{*}{ETRI} & \multirow{2}{*}{2014} & - & Built on Beacon. - \\  & & & & - & Simple architecture. - \\  & & & & - & reconfigurable some features in Floodlight. - \\ \hline \multirow{2}{*}{ONOS [46]} & \multirow{2}{*}{Java} & \multirow{2}{*}{Open Network Operating System project} & \multirow{2}{*}{2014} & - & ONOS stands for Open Network Operating System. - \\  & & & & - & Main concern is the scalability and the availability. - \\  & & & & - & has various commercial applications. - \\ \hline \multirow{2}{*}{DEFO [47]} & \multirow{2}{*}{Java} & \multirow{2}{*}{DEFO project} & \multirow{2}{*}{2015} & - & Standards for Declarative and Expressive Forwarding Optimizer. - \\  & & & & - & Increase the connectivity. - \\ \hline \end{tabular}
\end{table} 
Table 1: Features of available open source software defined networking (SDN) controllers. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Message Type** & **Message Structure** & **Message** & **Purpose** & **Reply** \\ \hline \multirow{4}{*}{Handshake} & - & \begin{tabular}{c} off\_header \\ (no body) \\ \end{tabular}