BACnet/IP Broadcasting Management Device (BBMD)
The BACnet/IP device service supports BACnet/IP Broadcast Management Device (BBMD) as a means of broadcasting messages on other sub-networks from the device service. BBMD works by installing a BBMD on each sub-network. Each BBMD contains a list of all the BBMD devices in the network, including itself. When a BBMD device receives a message, it will broadcast the message on its own sub-network and, if necessary, forwards it to the other devices contained in its BBMD device list.
Configuring Foreign Devices via BBMD
The BACnet/IP device service supports registering as a foreign device to a BBMD. This will allow the device service to contact BACnet devices on different subnets via the BBMD connection. To set up this registration, the following driver options should be configured:
| Environment variable | Description |
|---|---|
BACNET_BBMD_ADDRESS |
Points to the IP address of a BBMD device |
BACNET_BBMD_PORT |
Points to the port used by the BBMD device |
BACNET_BBMD_TIME_TO_LIVE |
The time that the registration will be active in the BBMDs Foreign-Device-Table The device service will automatically re-register before this time elapses The default time is 60000 seconds |
If the environment variables for BBMD are not set, it is assumed that BBMD is not used. In this case, all BACnet communication will occur on the same sub-network as the device-bacnet-ip container.