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Z-Wave topology and routing

The topology of the Z-Wave mesh is shown in the following figure using some of the device types and attributes associated with slaves and controllers. A single primary controller manages the network and establishes the routing behaviors:

Z-Wave topology including the single Primary Controller and four slaves and one enhanced slave. The bridge controller acts as a gateway to a WiFi network. A Portable Controller and Secondary Controller also sits on the mesh for assistance to the Primary Controller.

The routing layer of the Z-Wave stack manages the frame transport from one node to another. The routing layer will set up the correct repeater list if one is needed, scan the network for topology changes, and maintain the routing table. The table is fairly simple and simply specifies which neighbor is connected to a given node. It only looks forward one immediate hop. The table is built by the primary controller by asking each node in the mesh what devices are reachable from its location.

The use of source routing to navigate the mesh implies that as the message makes its way through the fabric, for every hop that receives the frame, it will forward the packet to the next node in the chain. As an example, in the following routing table, the shortest path from "Bridge" to "Slave 5" follows this logical path: Bridge | Slave 3 | Slave 2 | Slave 5.

Z-Wave limits the routing hops to a maximum of four.

A routing table of the preceding sample topology is given as:

Z-Wave Source-Routing Algorithmic Example

Portable controllers have a challenge in maintaining an optimal routing path; therefore, portable controllers will use alternative techniques to find the best route to a destination node.

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