earticle

한국어

It is essential to support real-time communication in networked control systems, such as automotive systems or smart factories. Several studies have been conducted to schedule real-time flows by adjusting their priorities using software-defined networking (SDN). However, because its architecture was not originally designed for realtime communication, unexpected challenges may occur if it is utilized without careful consideration. In particular, because SDN does not provide an atomic method for priority adjustment, some flows may violate their timing constraints by receiving additional interference during priority adjustment. In this paper, we propose a novel scheme to safely update the flow priorities in SDN-based real-time systems. Accordingly, we first analyze the challenge that may occur when adjusting flow priorities within a switch. We then develop a scheme that determines safe procedures for priority adjustment. By network emulations, we demonstrate that the above challenge occurs in 178 out of 300 flow sets, but our scheme can effectively prevent all of them.