# Routing Protocols for Low Power and Lossy Networks in Internet of Things Applications
## 4 Enhanced Routing Solutions for Internet of Things Networks
### Different Traffic and Mode of Operations' Support
\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} p{56.9 pt}} \hline \hline
**Proposal** & **Base Protocol** & **Objectives** & **Description** & **Strengths** & **Weaknesses** & **Target Applications** \\ \hline Co-RPL [73,74] & RPL & - Improve the mobility support of RPL & - Improving the routing solution based on the corona mechanism & - Provents an alternative mechanism to path recovery & - Requires changes in the default RPL messages & - General mobile wireless sensor network \\ \hline \multirow{4}{*}{mRPL [75]} & & & - & - & - & - \\  & & & & - & - & - \\  & & & & - & - & - \\  & & & & - & - & - \\  & & & & - & - & - \\ \hline \multirow{4}{*}{mRPL [75]} & RPL and smart-Hop & - Provide a fast and reliable mobility support in RPL & - Integrates the smart-Hop mechanism with RPL & - Interoperable with default RPL & - Interoperable with default RPL & - Short increment in the control messages’ length & - Wireless clinical monitoring applications \\  & & & & - & - & - \\  & & & & - & - \\  & & & & - & - \\  & & & & - & - \\  & & & & - & - \\ \hline \multirow{4}{*}{Mod-RPL [54]} & RPL & - Adjust RPL for hybrid networks (mobile and static nodes) & - Modification of RPL to limit the operation of mobile nodes & - Reduces the use of control messages & - Forbids the use of control messages & - Healthcare and medical applications \\ \hline \multirow{4}{*}{EKF-RPL [78]} & RPL & - Improves mobility support of RPL and signaling overhead of mobile nodes & - Uses the extended system for cellular film filter to predict nodes and the movement of mobile nodes and to reduce the movement of mobile nodes and to reduce the movement of mobile nodes and of mobile nodes & - Can increase the energy consumption & - Can increase the end-to-end latency & - Application with mobile nodes \\ \hline \multirow{4}{*}{BRPL [79]} & RPL and backpressure routing & - Enhances RPL to support mobility and dynamic traffic load & - Combines RPL, with backpressure routing & - Provides a considerable packet loss reduction & - Provides a considerable packet loss reduction & - - \\  & & & - & - & - \\ \hline \multirow{4}{*}{EMA-RPL [81]} & RPL & - - & - & - & - \\  & & & - & - & - \\ \cline{1-1}  & & & - & - & - \\ \cline{1-1}  & & & - & - & - \\ \cline{1-1}  & & & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison among the studied approaches for mobile nodes’ support. On the RPL, the supported traffic pattern is defined according to the utilized MOP, as described in Section 3.2. However, the choice of ideal MOP to be adopted also involves the consideration of the computational resources of the devices. Choosing the MOP with support to different traffic patterns (i.e., storing MOP) can require more hardware capacity and prevent \"weaker\" devices from running the protocol. In this case, a more reasonable solution could be to create a network with a different MOP being executed by the nodes with different capacities and making the \"weaker\" nodes work only as leaves. However, the presented scenario could face several interoperability problems once control messages are used and processed differently according to the MOP. Furthermore, as indicated on the RPL official document, each MOP should be adopted individually by the whole network. Thus, considering the limitations that may emerge for the using of different MOP simultaneously, [PERSON] et al. have presented the DualMOP-RPL [83], an improved version of RPL that supports both storing and non-storing MOP at the same time without reducing network performance. The protocol, to reach this objective, introduces five different enhancements in the RPL. The first seeks to prevent the network partition by allowing the \"weaker\" nodes, initially defined as leaves for running an MOP different from the root, to work as routers. The second enhancement allows non-storing nodes to send hop-by-hop DAOs, contrary to what happens in RPL, where non-storing nodes only send DAOs to the root.