User Manual

Overview
Merging BACnet/IP networks
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A broadcast is sent when starting up a BACnet client, for example, Desigo CC. This is necessary since this
BACnet participant is located in a remote IP segment and must registered on the network as a third-party
device.
Its broadcast is recognized on the BBMD for the new network, packed, and sent to all participants entered
in the BBMD.
BBMDs in other IP segments recognize this and send the Unicast as broadcast to all participants in its
segment.
Flexible room management uses, in other words, communication in one room over multiple room segments,
local broadcasts. Lots of devices on an IP network cause lots of broadcasts.
As result, large, complex projects must:
● Supply BACnet devices over layer 3 switches in its own IP segment (VLAN).
● Compile BACnet devices from the building, floor and plant scope, each on their own IP segments.
● Configure asymmetrical BDTs.
● Use a powerful PXG3 for BBMD functionality in the building scope.
3.4 Merging BACnet/IP networks
The following illustrates, based on this fundamentals, how to structure a small, mid-size, or large, up to a
multi-discipline project.
Small to mid-sized project
Up to 500 automation stations.
BBMD
BBMD
BACnet Broadcast
q
Layer 3 Switch
196.168.2.x 196.168.1.x