What is the architecture of BACnet?

The architecture of BACnet is based on the OSI layered model, which provides a framework for the communication between different devices and systems within a building automation system. But, the BACnet architecture consists of the 4 main layers, each with its own specific function:

• Physical Layer
• Data Link Layer
• Network Layer
• Application Layer

BACnet is a non-connection protocol, and there is no need for message segmentation and end-to-end error checking, compared to a connection-based protocol. Thus, the overhead of a discrete transport layer is not justified and the functions normally in a transport layer are delegated to the application layer. The session layer is also not needed, and since BACnet uses a fixed encoding scheme and offloads security to the application layer, a separate presentation layer is not needed.

The BACnet architecture also includes a set of standard profiles that define how different types of devices should communicate with each other. These profiles ensure that devices from different manufacturers can work together seamlessly within a building automation system.