RapidIO challenges Ethernet

To meet the performance requirements of the latest embedded products, designers have adopted serial fabric technology to interconnect chips, boards, and systems. Unfortunately, the industry has yet to decide on a universal interconnection scheme and design teams are left to evaluate the pros and cons of candidate architectures. To help in this decision making process, the RapidIO Trade Association recently released a 56 page whitepaper comparing two of the more popular architectures entitled “System Interconnect Fabrics: Ethernet Versus RapidIO Technology.” Although, as expected, the whitepaper concludes that RapidIO technology outperforms Ethernet for many embedded applications, the analysis exposes many technical details useful for either approach.

Ethernet was designed to connect a large number of endpoints over a shared cable with simplified hardware at individual nodes. Hardware needs to identify packet boundaries and the rest of the decoding process is left to software. RapidIO targets smaller networks with node hardware that can implement the entire protocol. In addition to the protocol analysis, the whitepaper provides a detailed comparison of quality of service, flow control, physical layers, high availability, hardware/software trade-offs, and usage models. The paper, authored by Greg Shippen, system architect for Freescale Semiconductor's Digital Systems Division, is available for download at the RapidIO Trade Association website in exchange for your name and email address.