Performance Analysis of a Secured BACnet/IP Network

Abstract

The Building Automation and Control networks (BACnet) protocol is one of the most widely used protocols in the building automation domain. In order to meet growing security requirements, an optional security architecture is defined in the BACnet standard. The purpose of this paper is to carry out a performance analysis on a BACnet/IP network, which is secured according to this security architecture. The additional time costs for client and server devices as well as the transmission costs are evaluated with regard to all levels of security defined in the standard. In this context, message signing with HMAC in combination with MD5 or SHA-256 and message encryption with AES-128 is investigated. To the best of the authors’ knowledge there are no works dealing with the performance of secured BACnet networks. The results should serve for further comparison with BACnet Secure Connect (BACnet/SC), which is currently under development and makes use of state-of-the-art security mechanisms like the Transport Layer Security (TLS).