# Routing Protocols for Low Power and Lossy Networks in Internet of Things Applications
## 4 Enhanced Routing Solutions for Internet of Things Networks
### Energy Efficiency and QoS Support
Each node should compute its ELT based on the traffic expectation generated by itself and its children, the possible necessary retransmissions, the time during the transmissions, and the transmission power of its radio. The authors also suggested the use of a mechanism to limit the parental exchange. Thus, the quantity of a control message is reduced, contributing to fewer transmissions and energy depletion. [PERSON] et al. proposed the ERGID (Emergency Response IoT based on Global Information Decision), a routing protocol that aims to provide both an efficient emergency response and reliable data transmission for IoT applications [89]. The proposal is based on two different mechanisms. The first, the Delay Iterative Method (DIM), classifies the nodes of a candidate route according to a global delay estimation. This mechanism is used to mitigate the problem of ignoring a valid path. Furthermore, DIM seeks to ensure real-time communication for emergency response applications and performs periodical updates in the routing table. The second mechanism, called Residual Energy Probability Choice (REPC), enables the use of residual energy information during the process of next node selection to forward a message. Thus, through the composition of these mechanisms, ERGID gives a low end-to-end delay (provided by DIM) and an efficient energy consumption distribution (supplied by REPC). A Neighbor Disjoint Multipath scheme attached to the LOADng routing protocol (LOADng + NDM) was introduced in [90]. The proposed scheme seeks to reduce the problems caused by local node failures and a lousy channel condition in specific areas. During its functioning, LOADng + NDM first creates a primary path between the source and destination nodes, which is frequently the shortest route. In sequence, the scheme tries to build a set of backup paths. These alternative routes need to attend to some requirements, such as: none of its nodes can compose the primary path, except to source and destination nodes; and none of its nodes can be a neighbor of the nodes that form the primary path, except to source and destination nodes. Using this approach and considering applications with P2P traffic, LOADng + NDM can overcome the default LOADng regarding throughput and latency. It is also important to emphasize that the proposed neighbor disjoint multipath scheme can be used with different routing protocols, including the well-known RPL. A framework for co-operating with routing protocols and providing QoS and energy efficiency for IoT networks was presented in [91]. Considering IoT scenarios that merge RFID and IEEE 802.15.4 devices, the proposed solution presents two mechanisms to improve the performance of both the routing protocol and the RFID tag-reading process. The first mechanism, named the Fuzzy Q-Algorithm (FQA), is a tag anti-collision protocol especially developed for IoT scenarios in which the tag reading process is realized for LLN devices equipped with RFID readers. FQA uses a fuzzy system to adjust the \(Q\) value [92] dynamically according to the tags' density and improve the reading process, making it faster and reliable. The second mechanism, called the Fuzzy System-Based Route Classifier (FSBRC), is a fuzzy system designed for joining four routing metrics (node energy, hop count, tags' density, and LQI) and defines a unique value that determines the route quality. The FSBRC uses the routing protocol control messages for transporting the metrics, which after being received, are used in the path quality computation. The nodes should select the path with higher route quality value to forward the data packets. Thus, the framework integrates both mechanisms to enhance the performance of IoT networks with heterogeneous devices and different wireless technologies. In the paper, the authors applied the proposed approach in the Directed Diffusion (DD) [93] routing protocol. However, they emphasized that the solution can be used with different protocols such as RPL and LOADng.