Implementation Of BACnet Protocol's Application Layer En/decoder Based On C++ Language

BACnet protocols comes from demands of the openness and interconnection of building automation and control networks.It's an openly data communication protocol for building automation and control networks to allow the integration of all types of digital building controllers into an inter-operative system. BACnet protocols uses compact model of RM/OSI,it does not include any functions of presentation layer, it is also flexible to describe the protocols.On the other hand ,being deleting presentation layer, application layer must fulfill functions of APDU's en/decoder that should be dong by presentation layer.Accordingly,it is very important to implement the APDU's en/decoder. The author studies BACnetAPDU that describe as ASN.1 and find that BACnet APDU is made of much intricate data,it's complex and burdensome to implement the BACnetAPDU's en/decoder using process-oriented method. This extrational function refers much popping stack and pushing stack,it wastes memory and influences running efficiency of protocol.Therefore, author clarifies a new function that use object-oriented method with C++ language to encapsulate BACnetAPDU,so that we can en/decode BACnetAPDU directly by using its definition.If so, we will en/decode BACnetAPDU easily.