Many special-purpose embedded systems such as automobiles and aircrafts consist of multiple embedded controllers connected through embedded network interconnects. Such network interconnects have particular characteristics and thus have different communication requirements. Accordingly, we need to frequently implement new protocol stacks for embedded systems. Implementing new protocol stacks on embedded systems has significant design space but it has not been explored in detail. In this paper, we aim to explore the design space of network protocol stacks for special-purpose embedded systems. We survey several design choices very carefully so that we can choose the best design for a given network with respect to performance, portability, complexity, and flexibility. More precisely we discuss design alternatives for implementing new network protocol stacks over embedded operating systems, methodologies for verifying the network protocols, and the designs for network gateway. Moreover, we ...