# Performance and Challenges of Service-Oriented Architecture for Wireless Sensor Networks
## 10 Discussion
\begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline
**SOA Approaches** & \begin{tabular}{c} **Service** \\ **Composition** \\ **Programming** \\ \end{tabular} & \begin{tabular}{c} **Active Service** \\ **Composition** \\ \end{tabular} & \begin{tabular}{c} **Services Integrated** \\ **with IoT** \\ \end{tabular} & \multicolumn{1}{p{56.9 pt}}{**Advantages**} & \multicolumn{1}{p{56.9 pt}}{**Disadvantages**} \\ \hline SCPQ [92; 93] & Not Supported & \begin{tabular}{c} Service based on \\ Greedy algorithm \\ \end{tabular} & Not Supported & 1. & QoS & \begin{tabular}{c} \\ and context-awareness \\ Minimizes Cost and \\ energy consumption \\ \end{tabular} & None & \\ \hline \begin{tabular}{c} Intelligent \\ SWSN \\ Middleware \\ [94] \\ \end{tabular} & \begin{tabular}{c} Proprietary \\ semantic \\ annotations for \\ WSDL and XML \\ \end{tabular} & Semantic Web & \begin{tabular}{c} Interoperability \\ using \\ WS-specifications \\ \end{tabular} & \begin{tabular}{c} Collects information through \\ the nodes can be reusable \\ resources in the real world \\ \end{tabular} & \
\begin{tabular}{c} 1. \\ 2. \\ 3. \\ 3. \\ \end{tabular} &
\begin{tabular}{c} Data redundancy \\ Network dynamics \\ Energy balancing \\ and Traffic \\ congestion problem \\ \end{tabular} \\ \hline \end{tabular}
\end{table} 
Table 8: Analysis of Service Composition Architectures for WSNs. Framework based on the DPWS gateway, which easily provides interconnection between IP networks and data centric WSNs and supports load balance and fault tolerance by using many gateway nodes for one WSN [97]. DPWS is based on middleware that can easily increase the overhead due to power consumption and latency [65]. Furthermore, it provides a secure service process through authorized parties, message integrity, and confidentiality. The DPWS is suitable for devices from certain regions. The DPWS cannot handle the overhead generated through web service, hence an efficient SOA implementation is used. Due to the overhead of SOAP and HTTP protocols, DPWS can be used. DPWS has the capability to secure services, since most of the applications do not require confidentiality for sensor data [65]. Most of the studies have not considered security mechanisms for sending the services/data from providers to the client, which can provide limitations to their approaches. In [33], a unique middleware based on Service-Oriented and message driven architecture for ambient aware sensor networks is presented. This approach does not provide a secure mechanism. Each node in the network should be registered to the main station to ensure security between sensor nodes and their station. The sensor nodes should encrypt their data through secure algorithms before sending it to their neighbors or the main station. Algorithms are needed to avoid any overhead or delay during processing and transmission of data. The QoS should also be taken into account to obtain more accuracy and a faster speed of operations. In [56], SunShine is integrated with distributed WSNs in the internet to perform a complex task. However, this approach has limitations in sending and updating patient information in a secure manner. The authors do not provide any security method to keep patients' data secure, especially during the communication between clients and their doctors. In [98], a novel security mechanism is proposed for WSNs through SOA. In this architecture, the security measurement is used to address the flow of WSNs in a secure manner. The security is applied in the message level of the node, which is located near the cluster head and has the capability to recognize the identity of the sensor through SOA. The main goal of this approach is to reduce power usage and maximize the network's lifetime by decreasing the size of processed information in the sensor nodes [98]. This method has the capabilities to interact, manage, and extend the system easily.