Wi-SUN networks communicate using standard Internet technologies adapted for low-power, long-range wireless links. At the core is IPv6, which enables end-to-end addressing and routing across the mesh and out to external IP networks.

Because Wi-SUN operates over constrained wireless links, it relies on 6LoWPAN (IPv6 over Low-Power Wireless Personal Area Networks) to make IPv6 communication efficient in these environments.

This section introduces how communication works in Wi-SUN networks, including IPv6 basics, 6LoWPAN optimization, and the two common communication paths.

IPv6 and 6LoWPAN in the mesh

Wi-SUN devices communicate using standard IPv6 packets, just like devices in any modern IP network. Every device (Border Router, router node, or leaf node) is assigned one or more IPv6 addresses, which enables direct reachability.

6LoWPAN adapts IPv6 for low-power, low-bandwidth radio environments by compressing headers and fragmenting packets to fit IEEE 802.15.4g frames. These details are handled transparently by the devices.

Addressing and reachability

Address configuration happens automatically when devices join the network. The Border Router advertises an IPv6 prefix, and nodes form or obtain their addresses accordingly.

For detailed information about IPv6 address types and assignment, see IPv6 addressing.

Once assigned an IPv6 address, a device can send and receive packets across the mesh or through the Border Router to external IP networks.

Communication paths

Two common communication paths are used in Wi-SUN solutions. Both are valid, and many deployments use a mix of the two.

Direct to server

Nodes communicate directly with a remote server using their routable IPv6 addresses. The Border Router forwards IPv6 traffic between the mesh and the upstream network.

This approach works best when your server can accept connections from many devices and there is a routable path (public IPv6 or VPN) from the mesh to the server.

Local communication

Nodes send their data to the Border Router, which runs an application that aggregates, processes, or forwards the data. The Border Router can then relay messages to a cloud service or local system.

This approach is common when nodes must be isolated from external networks or when local processing and protocol translation are required.

Next steps

For a practical view of supported communication methods, see Communicate on the network. For implementation details, see Send and receive data for the XBee for Wi-SUN and Send and receive data for the XBee Hive for Wi-SUN Border Router.