Managing group addresses

A ‘group address’ is a concept that simplifies data transfers (see Section 6.5) to multiple nodes/endpoints. It is a collective 16-bit address which refers to a group of destination endpoints (that may be located on different nodes). So, for example, when a group address is specified as the destination address for a data transfer, the data will be delivered to all the nodes/endpoints in the associated group. It is the responsibility of the wireless network application to allocate and manage group addresses on a network-wide basis.

A node which is to receive group-addressed communications must have a Group Address table. This table contains information about all the groups to which endpoints on the node belong - that is, each group address and the associated local endpoint numbers. The table is consulted on receiving a data packet with a group address - if the group address exists in the table, the packet is passed to the corresponding endpoint(s).

A Group Address table is created on a node using the ZPS Configuration Editor. The table can then be maintained by the application as follows:

• An endpoint can be added to a group by calling the function zps_eAplZdoGroupEndpointAdd() on the local node (which contains the endpoint).

• An endpoint can be removed from a group by calling the function zps_eAplZdoGroupEndpointRemove() on the local node (which contains the endpoint). Alternatively, zps_eAplZdoGroupAllEndpointRemove() can be used to remove a specified local endpoint from all groups to which it belongs.

The group addresses used in a network are defined by the application developer.

Parent topic:Application coding with ZigBee PRO APIs