How is the ZigBee protocol employed when it comes to radio frequency identification?
There are many different types of active RFID transponders. Most are designed to awaken and periodically broadcast a signal containing their unique serial numbers. Readers pick up the signal, after which a variety of techniques, such as triangulation, are used to determine the object's location. Another type of active tag is designed to wake up within a certain zone around a reader, and then broadcast its unique ID.
The ZigBee protocol can be utilized in a variety of ways, but it is usually used to enable sensor devices to communicate with one another in a mesh network. If, for example, a node in the network has a moisture sensor and it detects moisture, that information is passed from one node to the next until reaching a host system. Active RFID transponders are not designed to work this way; the tags communicate directly with the reader, not with one another.
—Mark Roberti, Founder and Editor, RFID Journal