## 4 Proposed Model of SACFIR and SAMCFIR
### Network Forwarding Phase (NFP) of SACFIR and SAMCFIR  
The real communication of network traffic transportation happens during NFP, when NSP has decided upon the reconfigurations of the updated forwarding rules for FECHs and non-FECHs. Initially, all nodes collect environmental reports by using multi-sensing utilities and MCU drives the digital reports from a continuous analog signal. Because sensor nodes are reprogrammable by SDN controller, we can reset their sensing preference according to the required applications. The SDN controller centrally sets the application characteristics during the initial hello packets. However, for routing, the analytical operation proposed model develops a threshold-based nodes sensitivity operation. A random number is generated and compared with the defined threshold preference which is decided by the network administrator for routing algorithm. The sensor nodes produce results according to the threshold values. The SACFIR routing algorithm is responsible for measuring three types of environmental parameters; temperature, pressure and humidity. Analytical operation of threshold based application-awareness is represented by equation:  
\[App-Thresh=\left\{ \begin{array}{ccc}Temperature&If&Ran-Num<1 stlevel\\ Pressure&If&1 stlevel<Ran-Num>2 ndlevel\\ Humidity&If&Ran-Num>2 ndlevel\end{array} \right. \tag{32}\]  
Similarly, the SAMCFIR routing protocol is responsible for measuring temperature and pressure environmental attributes but it gives the flexibility to transmit critical data at sudden direct transmission without any significant delay. This is achieved by setting a critical transmission threshold, which can be calculated by the following equation:  
\[App-Thresh=\left\{ \begin{array}{ccc}Critical&If&Ran-Num<1 stlevel\\ Temperature&If&1 stlevel<Ran-Num>2 ndlevel\\ Pressure&If&Ran-Num>2 ndlevel\end{array} \right. \tag{33}\]  
Application-specific transmission constitutes the major difference between SACFIR and SAMCFIR. Another major difference is the path selection difference in the transmission phase. SACFIR utilizes a unique multi-path inter-cluster communications for all types of environmental reports while SAMCFIR follows the same multi-path communication but also triggers the nodes for direct transmission when critical information is generated. All of these application-specific threshold priorities are reconfigured by the SDN controller during the settling phase. The network transmission phase can also be called the forwarding phase which is guided by the SDN controller logics at the control layer. The detailed flow-chart of the proposed models is shown in Figure 7.  
Figure 7: Flow chart proposed models. Optimization in Multi-Hopping Communication  
Optimization of the network throughput becomes crucial in the case of implementing the multi-hopping technique for limited resources of WSNs. The SDN controller develops graphical representation of the FECHs and computes energy and associated link capacities. This whole idea is extracted from the idea of multi-commodity flow. Graphical representations of the selected FECHs are driven by \(G_{FECHs}=(V_{FECHs},E_{FECHs})\) in which M vertexes, \(V_{FECHs}=1,2,\ldots,M\), indicates FECHs and \(E_{FECHs}\) edges\((i,j)\) communicate FECHs within the transmission range. Let us assume that there are \(L\) pairs of \(FECHs_{V}(S^{l},D^{l})\) for (\(l=1,2\ldots,L\)) which indicate the pair of source and destination \(FECHs_{V}\) from the set of \(L\) commodities for which a transmission path is needed to be found on the graph \(G_{FECHs}\).