Each device has a configurable number of endpoints, with a minimum of 2. Endpoint 0 is always the ZDO (see below), and can be used to query the device about its capabilities.

Endpoints 1-240 are available to be used by the application, and they provide unique “addresses” on the same device. In the basic case, only a single endpoint is used.

Note! Users familiar with TCP or UDP will recognize this as very similar to the concept of a “port” — in this model, except endpoint 0, endpoints do not have specific defined applications so it is necessary to query a device at run-time to find out which endpoints are available and which application profiles each provides.

Single Endpoint

In this case, all messages sent to and from the light and light switch use endpoint 1 (or endpoint 0 in the case of ZDO messages).

This configuration is sufficient for many applications.

Multiple Endpoints

In this example, the single light switch box houses three separate light switches. Each light switch is capable of controlling a different light, but they all share the same ZigBee radio and processor.

This works because the light switch implements three different endpoints, each of which implements the HA profile. When messages are sent, they specify which endpoint they are coming from and which endpoint they are going to.

Common Questions

• Does a device have to use endpoints in order?

No, ZigBee does not require you to use endpoints in order. Your application can use endpoint 4 without using 1, 2, or 3. One consequence of this is that you cannot depend on an unknown device implementing the profile you want to talk to on a particular endpoint — you must query the device at run-time to determine which profile is running on which endpoint.

ZDO and ZDP

The ZDO provides network management capabilities that devices can use to learn about each other, about the network in general, or for managing stack-level functionality.

Many features of the ZDO are available on all ZigBee/ZigBee PRO devices, making them useful as an interoperable way to gather and manage system properties on a ZigBee network.

The ZDO uses an over-the-air messaging format known as the ZigBee Device Profile (ZDP).

Those interested in more practical detail concerning EmberZNet should read Using the ZDO with EmberZNet.