Broadcast Messages

In Zigbee communications, most messages are sent from one node to another (unicast). This can either be done using the destination node's Short Address or MAC Address. Zigbee also supports a broadcast message, whereby one message may be sent to many other messages. This can be done for time synchronization, or other type of events. Note that broadcast messages should be used very sparingly, as they consume much network bandwidth. It's also difficult to know whether all devices have received the message.

To broadcast a message, send a message using one of the broadcast short addresses, as follows:
 * 0xFFFC - All Routers and Coordinator
 * 0xFFFD - All devices with receiver turned on
 * 0xFFFE - Reserved for binding
 * 0xFFFF - All devices in the network

Note that there may be significant latency in propagating the message out to all the nodes. This is determined by the size of the network, and in particular the depth (number of hops).

If you wish to time synchronize devices, a better way is to have the node that needs synchronization (e.g. a router) periodically request time from the coordinator or server. The coordinator then replies back with a unicast message to the requesting node. In this way you minimize network traffic and can be assured that all devices were updated.