December 2008
Column -

Babel Buster Network Gateways: Big Features. Small Price.
Control Solutions, Inc. - Minnesota

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BAS Use of Ethernet/IP Infrastructure

Simply put, should a BAS use its own dedicated Ethernet/IP system, or should it use that provided for the building’s business-enterprise communications and managed by the IT department?

 Paul Ehrlich & Ira Goldschmidt
Building Intelligence Group

As published

December Issue - Column 

All of the world’s communications systems appears to have of converged on the use of the Internet Protocol (IP) with Ethernet connections being the preferred method for local connection. BAS systems have standardized on this type of connection and many owners are looking to a future where even the VAV box and light switch will be on the network. If so, then why has this issue become one of the most vexing BAS design challenges? Simply put, should a BAS use its own dedicated Ethernet/IP system, or should it use that provided for the building’s business-enterprise communications and managed by the IT department?

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For us there are many obvious reasons why the use of the enterprise network is the right solution:

  • Dedicated BAS Ethernet/IP communications is a duplication and an added construction cost

  • It often requires additional specification design by the BAS designer (for the dedicated Ethernet/IP system) - another added cost

  • Without careful coordination the BAS Ethernet/IP equipment may not meet the facilities’ IT standards (even though it is a separate system this still can be a concern to IT folks)

  • Enterprise networks are typically higher quality, offer higher reliability, and are actively managed with staff ferreting out potential attacks and problems.

  • Determining how and where the Ethernet/IP LAN connects to internet (for remote communications) can sometimes lead to confusion

contemporary That being said we are not the IT folks that sometimes are skeptical or even resistant to being saddled with the added communications switches, cabling and support for adding BAS connections to the enterprise network. We are also not the ones that are justifiably concerned with the risks of connecting building systems to the enterprise network including potential traffic, threats and other issues that could potentially wreak havoc with the IT infrastructure. Unfortunately, as BAS designers we are not always best equipped to argue these issues with IT experts and frankly they are not always the most open and receptive folks to work with.

Clearly the BAS designer is faced with the choice between fighting for what is believed to be the best engineering approach vs. taking the path of least resistance by avoiding the potential IT battle. You could say that this is an example of the consulting engineer’s dilemma when confronting many building design issues. Also it is not to say that placing the BAS system on the enterprise network is not without its challenges also which range from other IT coordination issues to schedule impact to network security. We’ll cover that side of the issue in a future column.

About the Authors

Paul and IraPaul and Ira first worked together on a series of ASHRAE projects including the BACnet committee and Guideline 13 – Specifying DDC Controls. The formation of Building Intelligence Group provided them the ability to work together professionally providing assistance to owners with the planning, design and development of Intelligent Building Systems. Building Intelligence Group provides services for clients worldwide including leading Universities, Corporations, and Developers. More information can be found at  We also invite you to contact us directly at or



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