# Reliable Fault Tolerant-Based Multipath Routing Model for Industrial Wireless Control Systems
## 3 Methodology and System Model
### Graph Routing in WirelessHART  
The WirelessHART standard specifies three categories of graph routing for accomplishing various transmission purposes: broadcast, uplink, and downlink. The broadcast graph is used to send general messages from the gateway to each node in the network. Each field device's data is uploaded to the gateway using the uplink graph. Finally, the gateway uses the downlink graph to transmit unicast data to unique field devices. The  
\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
**Reference of** **IWSN** **Simulator** & **Objective of Work** & **Wireless Standard** &
\begin{tabular}{c} **External Interface Implementation,** \\ **Network Management,** \\ **Communication Stack** \\ \end{tabular} & **Metrics of Evaluation** \\ \hline
[37] & Security & WirelessHART & Network Manager, Complete Stack of WirelessHART & Rate of successful transmitted data collection at the presence of security attack \\ \hline
[39] & Link failure impact on industrial process & WirelessHART & Network Manager with fixed allocated resource, full stack of WirelessHART, the challenge problem known as Tennessee Eastman Process Control & Imperfect wireless links with process parameter variation \\ \hline
[42] & IWSN protocols simulation Comparison & ZigBee, WirelessHART & MAC and PHY layers, basic layer application & RF signal level, energy consumption, communication statistics \\ \hline
[43] &
\begin{tabular}{c} Energy consumption based-WSN Optimization \\ \end{tabular} & WirelessHART, ISA100.11a & MAC, PHY layers & Energy consumption based-Network lifetime \\ \hline
[47] &
\begin{tabular}{c} Energy consumption based mathematical model \\ \end{tabular} & IEEE 802.15.4 & Not applicable & Consumption rate of energy \\ \hline
[48] &
\begin{tabular}{c} Load processing impact on communication \\ \end{tabular} & IEEE 802.15.4 & PAN coordinator and IEEE 802.15.4 stack & Network delay and CPU load performance \\ \hline
[53] &
\begin{tabular}{c} Discussing Signal quality on the deployment of IWSN. \\ \end{tabular} & WirelessHART, ISA100.11a & Not applicable & Quality of RF signal \\ \hline
[24] &
\begin{tabular}{c} WirelessHART network simulation \\ \end{tabular} & WirelessHART & Network Manager, full WirelessHART stack & Energy consumption, reliability, PDR, management overhead \\ \hline
[54] & \
\begin{tabular}{c} Testbed based HIL simulation \\ \end{tabular} & IEEE 802.15.4 &
\begin{tabular}{c} Network management, TinyOS stack \\ \end{tabular} & Consumption of energy \\ \hline
[57] &
\begin{tabular}{c} Hardware and simulation integration at RF level \\ \end{tabular} & IEEE 802.15.4 & Application model, MAC, Physical layers & Strength of signal \\ \hline The proposed fault tolerance based multipath routing & Implementation of Multipath routing on WirelessHART simulator & WirelessHART & Existing Network Manager, full WirelessHART stack & Average latency, lifetime, packet delivery ratio \\ \hline \hline \end{tabular}
\end{table}
Table 1: Existing IWSN simulation Methods.  
network manager creates and updates all these routing graphs, which are then downloaded to each node.  
Figure 2 demonstrates an example of graph routing in WirelessHART mesh networks namely broadcast (\(G_{B}\)), uplink (\(G_{U}\)), and downlink (\(G_{d}\)) graphs. Each of the routing graph topologies consists of four nodes, two access points (AP1 and AP2), and one gateway (GW). The arrows in Figure 2 represent the hops in the routing direction, from source to destination, where the message will be forwarded.