Zigbee Mesh Networking#

Embedded mesh networks make radio systems more reliable by allowing radios to relay messages for other radios. For example, if a node cannot send a message directly to another node, the embedded mesh network relays the message through one or more intermediary nodes.

EmberZNet PRO supports three types of mesh network topologies, as shown in the following figure:

  • Star Network

  • Full Mesh Network

  • Hybrid Mesh Network

Star, Full Mesh, and Hybrid Mesh NetworksStar, Full Mesh, and Hybrid Mesh Networks

Note: Blue devices in the above figure are end devices and can be sleepy or mobile. See Network Node Types for more information about end devices.

Star Network#

In a star network, one hub is the central point of all communications. The hub can become bottlenecked with network/processing bandwidth. This topology is not very mesh-like, and transmission is limited by the hub’s communication radius. Outlying nodes can be battery powered. In the EmberZNet PRO stack, this topology is formed by a group of end devices with a coordinator node as their parent. The coordinator node serves as network hub.

Full Mesh Network#

In a full mesh network, all nodes are router nodes, including the coordinator after it forms the network. Because all nodes can relay information for all other nodes, this topology is least vulnerable to link failure; it is highly unlikely that one device might act as a single point of failure for the entire network.

Hybrid Mesh Network#

A hybrid mesh network topology combines star and mesh strategies. Several star networks exist, but their hubs can communicate as a mesh network. A hybrid network allows for longer distance communication than a star topology and more capability for hierarchical design than a mesh topology. This topology is formed by the EmberZNet PRO stack, using router devices as hubs for the star subnetworks, where each hub can have end devices attached to it.

The choice of topology must take into consideration which nodes are line-powered or battery-powered, expected battery lifetime, amount of network traffic required, latency requirements, the cost of the solution, as well as other factors. See Software Design Fundamentals, for more information.