What does a BACnet topology look like?

BACnet topology BACnet architecture MS/TP and IP
Is there a common architecture for a BACnet network?

What defines a BACnet network? There are certain essentials you can expect to find on a basic BACnet network, according to KMC Controls: “A simple network requires only two or more controllers, an operator workstation and network wiring.”

There are many physical topologies that can be used to design your BACnet/IP networks. The really important part to understand about the BACnet topology is its logical architecture, though: the way that data actually travels from device to device. There’s a basic hierarchy that most BACnet systems follow.

Essentially, a Building Management System (BMS) connects to a data aggregator. That aggregator connects to different zones or applications via MS/TP connections, or to different IP devices via IP connections. Data is shared from the zones or devices, up to the aggregator and BMS. Simple!

BACnet architecture topology MSTP and IP

The devices will all be assigned a MAC address and BACnet device instance number and, in the case of an MS/TP network, they’ll be configured with the same baud rate. In a BACnet/IP network, of course, you’ll have IP addresses and will need a BACnet Broadcast Management Device (BBMD), as well. (Learn more about BBMDs.)  

There are also flat networks, which are not divided into subnetworks or “hierarchies” with individual switches. This design is used to reduce costs, since purchasing switches can become quite pricey. Flat networks do work well on home or very small business networks. The larger your network, though, the less feasible flat networks become. They’re susceptible to speed and scalability issues.

If you’re looking for additional information, be sure to check out Bill Swan’s guide to internetworking with BACnet and BACnet International’s tutorial.

Recent Blog Posts

At Optigo, we love learning about industry trends: artificial Intelligence and machine learning, data tagging, the push towards personalization in our buildings… 

There are many different issues that can crop up on IP and Ethernet networks. 

It is a truth universally acknowledged, that an MS/TP network rife with problems probably has bad wiring. 

In building automation, there’s a growing — and very apparent — need for Project Haystack and tagging. 

BACnet gets compared to a lot of other protocols on the market, including LonWorks, Modbus, and KNX. In this article, we break down the advantages and disadvantages of each protocol.

Recent Projects

Data center expansion with OTI and Optigo Connect


Stack Infrastructure is a portfolio of hyperscale computing data centers. OTI completed work on Phases I and II, and returned for the Phase III build-out of a 4-megawatt data hall and brand new central plant. The Optigo Connect network put in place in Phases I and II was expanded on this project. The team achieved quick roll-out of a large, multi-service redundant network using the Optigo OneView management interface. Going forward, the facility management team can use OneView to remotely monitor equipment, manage power usage, and meet up-time goals.

Optigo Connect MR Soluciones The Landmark


The Landmark is a sophisticated mixed-use high-rise in Mexico. The owners wanted to integrate all OT systems in the skyscraper, while maintaining separate networks for each application. The Landmark is the fourth joint project between Optigo Networks and MR Soluciones. Together, these companies provide robust services to meet any challenge.

Australian Bureau of Statistics at 45 Benjamin Way with Delta Building Automation


Delta Building Automation (Australia) had a big job renovating the Headquarters for the Australian Bureau of Statistics (ABS) at 45 Benjamin Way. The building owner wanted to improve the building’s energy use and increase their National Australian Built Environment Rating System (NABERS) score to more than 4.5 stars, out of a possible total of six. Securing the network both internally and externally was a big priority, as well.

Penn State University Optigo Networks Visual BACnet


When Tom Walker looked at Penn State University’s Navy Yard network, he saw huge issues. The system was busy and loud, to the point where the overrun network was bringing down the entire building. Because this was happening on the MS/TP network, pinpointing the problem would mean boots on the ground to segment and test the chain, piece by piece.

Penn State University Optigo Networks Visual BACnet


When Tom Walker first started working at Penn State University four years ago, there were a lot of network issues. Buildings were dropping offline. Broadcast traffic was pushing 90,000 packets per hour. Walker was on the phone almost every single night because devices were down or had to be reset.


Torre Manacar Mexico City Optigo Connect


When MR Soluciones began work on Torre Manacar, they knew they needed a flexible and scalable network infrastructure to support a wide array of integrated systems. Optigo Networks was a natural fit for the massive project, designing a robust network at a competitive cost.



Short Pump Town Center, an upscale retail center, underwent a complete renovation in 2014. The flexibility of Optigo Networks’ solution meant the retail center’s unknown final design was not a barrier to placing IP surveillance equipment in the field.



Optigo Networks connected New York-based Boulevard Mall’s security surveillance devices in December 2015, using a Passive Daisy Chain topology.

Visual BACnet tech support team


One tech support team at a manufacturer purchased an account with Visual BACnet in April 2017, for technical problems around the world.

Aster Conservatory Green Optigo Connect


The Aster Conservatory Green is a community comprising 352 residences across 24 low-rise buildings. The buildings use advanced surveillance and access control technology, including 40 HD video cameras and 60 FOB-access-tele-entry points for access control.