BACnet IP vs. BACnet MSTP

We’ve spent many years on our blog discussing several features and benefits of building automation systems—from top metrics a building management system should be tracking, to troubleshooting common building automation system issues and most recently, how building automation controls can impact accelerated growth strategies for marijuana grow rooms. One question you may still have that we’ve yet to address is, “How does communication happen between my equipment through my building automation system (BAS)?” The answer: building automation and control networks, or BACnet for short.

How does BACnet work?

BACnet is considered the best-practice communications protocol for building automation and control networks, simplifying BAS equipment and open-data communication, and utilized for networks that leverage the ASHRAE, ANSI and ISO 16484-5 standard protocol. As simplified by KMC Controls, BACnet allows for:

  • Increased interoperability across vendors, so you’re not tied to a single brand
  • Consolidated workstations, making it easier for share-data to flow to one place rather than from vendor-specific platforms
  • Defined object types and services that their devices support—making it a communication protocol that not only focuses on how messages move or how data is transferred, but also defines how the data is discovered by and shared between other devices or software

While BACnet protocol supports a number of different networks and physical media to connect devices, BACnet IP (Internet Protocol) and BACnet MSTP (Master-Slave/Token Passing) are two of the most common networks. BACnet MS/TP has been the standard for the last several decades, but the introduction of BACnet IP is shaking up the future of the building controls industry. 

The differences between BACnet IP and BACnet MS/TP

What does BACnet MS/TP mean?

BACnet MS/TP is a token-passing protocol which uses standard serial ports on microcontrollers and EIQ-485 transceivers. While it offers a slightly lower cost for BACnet Integration, according to Cimetrics, BACnet MS/TP is essentially the dialup of communication in relation to ethernet. Compared to BACnet IP (which we’ll dive into soon), BACnet MS/TP is much slower and less secure, a major concern for IT managers—especially in schools and health care facilities. To invest in BACnet MS/TP today would be an investment in old technology.

What is MS/TP protocol?

As defined by Cimetrics, token passing is a networking access control mechanism. Utilized by MS/TP, this method only allows for master nodes to initiate the transmission of data only when it holds a token. After one master node with the token sends frames, the token is passed to the next master node. This token-passing process from one master node to another is what makes BACnet MS/TP communication much slower than BACnet IP.

In addition to BACnet MS/TP offering no security, data is also required to go through a network controller, like a JACE—requiring a “middle man” which also slows down data travel time.

What does BACnet over IP mean?

BACnet IP is the control industry’s new preferred communication protocols, allowing systems to talk to each other over a network, like Internet of Things (IoT) technology—cutting out the middle man. Unlike BACnet MS/TP, requiring data to be transferred and stored in a controller like a JACE, IP software stores through cloud-based software, making it much more secure.

Additionally, as discussed by Scott Cochrane, President and CEO of Cochrane Supply & Engineering in Automated Buildings, all new controllers and devices on the market are IP-enabled, including but not limited to actuators, sensors, light switches, gateways, cameras, thermostats and more. These IP-enabled devices are built to pair much more seamlessly with BACnet IP, but only when paired with Application Programming Interface, or API. As Mr. Cochrane puts it, “Devices that come with a documented rich API are the open solutions of the future,” giving users an impressive menu of software choices in how to integrate, incorporate, secure, manage, access and play with that IP controller or device."

Control Solutions recommends our clients invest in BACnet IP and API to optimize the building for even more new technology to come in the future—as well as for the highest level speed and security.

Security over BACnet IP vs. BACnet MSTP

BACnet MSTP offers no way to prevent a security breach in a traditional system, whereas BACnet IP has the capability to be protected from external users attempting to hack or breach a system. As reported in EdScoop, the district had to extend their winter break by a full week to remedy the issue and bring all systems back online.

While several of the district’s critical systems like HVAC, telephones, copiers and classroom technology lost function, student and staff information was thankfully not compromised; however, this incident clearly cost the district a substantial amount of time, money and stress that could have been avoided with BACnet IP. This sort of incident could cause even more issues when personal information is compromised—especially in hospitals or pharmaceutical companies where operational systems are critical and patient information is extremely sensitive.

Why is BACnet IP is the best choice?

As summarized by Exciting IP, there are myriad advantages of using IP networks to monitor and control your BAS, such as:

  • Pervasiveness: IP networks would make all proprietary cables and cabling interfaces of BMS unnecessary, cutting costs
  • Remote Monitoring: IP networks can be monitored either through MPLS/VPN networks or through the internet
  • Consolidated & centralized monitoring
  • Real-time alerting on the health and safety parameters of multiple devices
  • Common scripting languages can be used
  • Reduced operational costs due to energy savings with automated energy conservation features
  • Reduced labor costs: By using ethernet cable to communicate between controllers, it becomes a much simpler process to terminate this communication wire than it would on MSTP or LON protocol
  • Eliminated communication issues when completing a project due to stripped wires or incorrect termination of the communication wire when using MSTP or LON protocol
  • Reduced programming time: BACnet MSTP or LON can take hours to communicate between controllers whereas BACnet IP can only take minutes
  • Computer programming logic may be applied to control utility parameters
  • WiFi can be used to monitor and communicate with BAS sensors/units
  • Disparate BMS systems (e.g. lighting and HVAC) can communicate over the same IP network
  • Customized web pages can be created for the facility manager’s operational use

Interested in learning more? Control Solutions, Inc. are the experts

Interested in implementing or retrofitting BACnet over IP in your facility? Our team is happy to discuss your project needs and explain further why BACnet IP is the smarter investment. Contact us today to set up a consultation call. 


KMC Controls
Cochrane Supply
Automated Buildings
Exciting IP