Fieldbus
Communication
•
213
BACnet/IP
WAGO-I/O-SYSTEM 750
BACnet/IP Controller
4.2.1.6.2.2
BACnet/IP in Foreign Networks
If a device is connected to one subnet and would like to receive broadcasts
from another subnet or send to another subnet, BBMDs are required in both
subnets (see Fig. 4-4).
For a device to communicate that does not have a BBMD in its own
(sub)network and therefore becomes a Foreign Device (FD), the other
BACnet/IP (sub)networks must have BBMD/FDs (see Fig. 4-5). The foreign
devices register with this BBMD/FD using their IP addresses. In this way,
broadcasts from other subnets can be received or can be sent to these net-
works.
IP
router
IP
router
Internet
BBMD/FD
BACnet
BACnet
BACnet
device
device
device
BBMD/FD
BACnet device
BACnet
BACnet
device
device
Network 1
Network 2
Foreign device
1.Registration
2.Unicast to BBMD/FD
3.Transforming/sending as broadcast
Fig. 4-5: Registration of a foreign device
G083011d
