Real-time performance of an open-source protocol stack for low-cost, embedded systems

Modern embedded devices often require some form of network connectivity, to offer features like remote configuration, diagnostics, and firmware updates. The availability of open-source, lightweight, and portable protocol stacks, makes this goal relatively easy to accomplish, even on very low-cost devices. Interoperability is guaranteed because they implement, at the very least, the TCP/IP and UDP/IP protocols on an Ethernet interface. However, these applications are quite undemanding for what concerns real-time and, for this reason, little is known about the real-time characteristics of the underlying protocol stacks. This paper shows that an open-source protocol stack, when properly coupled with a real-time operating system and an Ethernet interface, can indeed reach an acceptable performance level and thus support an Ethernet-based field bus protocol on the device side.