A bandwidth allocation scheme for scalable coherent interface (SCI) based avionics real-time network

IEEE Standard 1596 Scalable Coherent Interface (SCI) a COTS technology, is one of the candidate architectures for a "Unified Network." Its basic topology is a buffer insertion ring. Messages can be transmitted concurrently on the ring, thus can achieve high throughput. But problems exist when using SCI in real-time applications. The difficulty mainly results from its buffer-insertion feature which makes the latency of real-time messages difficult to predict. The goal of this study is not to solve the problem of using SCI for general real-time applications but to provide a bandwidth allocation scheme for synchronous messages transmission in avionics environments. The scheme is based on features of avionics interconnections and the bandwidth allocation scheme in slotted ring. An improved SCI protocol is proposed and schedulable network utilization is given.