A mesh topology comprises multiple IoT devices that connect directly, dynamically, and non-hierarchically to as many other devices as possible. The devices of a mesh network cooperate with one another to efficiently route data from producers to consumers within the network. Specifically, in a mesh network, messages travel from one IoT device to another until they reach their destination (e.g., an IoT gateway). Hence, every IoT device acts as data capture and transmission endpoint, while at the same time operating as a repeater that relays data from other nodes. In full mesh networks, all nodes act as repeaters and relay nodes. However, there are also partial mesh network deployments, where only selected devices to act as repeaters and/or relay nodes. In practice, mesh IoT networks are used to extend the coverage of popular short-range wireless protocols (e.g., Zigbee and WirelessHART).
Mesh topologies present many advantages, which is the reason why they are increasingly used in IoT deployments. Specifically, in mesh networks, IoT data can be transmitted from different devices simultaneously, which leads to high throughput and supports high traffic scenarios. Additionally, mesh networks do not have any single points of failure: if one component fails, it is always possible to find an alternative route.
The downside of mesh networks lies in their complexity, which complicates their setup and increases the effort needed for managing and maintaining them. Moreover, the density of a mesh network’s connections is a setback to their scalability. Despite the low power required for data transmission, mesh networks are energy-intensive systems. This is due to the large number of relay connections involved in typical mesh networks - nodes must be continually available to relay messages, which can drain their battery in short time. Furthermore, mesh networks have high deployment costs. This is mainly due to the need for deploying many repeaters given the very short range between devices. Finally, one of the main disadvantages of mesh IoT topologies is that they are susceptible to security attacks. Specifically, it is theoretically possible to hack a mesh network by attacking a single node or repeater. Therefore, in an IoT network with many nodes and repeaters, hackers are provided with many opportunities to launch adversarial attacks.