Backplanes at 10 Gbaud ñ try that with PCI Express!

Q&A with Tom Cox, Executive Director, RapidIO Trade Association

1Tom Cox, head of the RapidIO Trade Association, knows a thing or two about VME backplanes due to his decades in the embedded and VME industries. So when he says that Serial RapidIO is the best way to communicate inter-card, it’s not a hollow promise. Our long-distance interview with Tom explores the technology, the systems, and the whole RapidIO ecosystem. Edited excerpts follow.

VME: To provide context for our readers, can you acquaint us with the focus of the RapidIO Trade Association, aside from the obvious?

COX: The RapidIO Trade Association brings together a powerful ecosystem focused on aiding developers who build critical embedded systems using the highly robust RapidIO interconnect architecture. Our members represent a veritable "who's who" of leading embedded companies joining in a collaborative environment to deliver the best critical mass of products on the market today. RapidIO-based products include a wide assortment of end-points, which can minimize the amount of bridging required in a design. In addition, we work closely as partners with VITA and PICMG to complement our intense focus on interconnects for the embedded marketplace.

VME: Standards Development Organizations (SDOs) such as IEEE,, VITA, and others are making their mark on technology, but have they helped or hindered marketplace competition?

COX: Open standards groups, like the RapidIO Trade Association, by their very nature create a common base and foundation on which existing markets grow and new markets are created. When implemented correctly, they spawn innovation and allow OEMs the freedom to develop new applications that take advantage of powerful enabling devices and systems. Without open standards, the marketplace would be fragmented, interoperability would be virtually nonexistent due to the plethora of proprietary designs, and innovation would stagnate. Just look at the impact on the PC by PCI - perhaps the best example of the fruits of open standards organizations.

VME: On which technology issues is the RapidIO Trade Association focusing the majority of its efforts?

COX: Without a doubt, our primary focus includes the technology issues surrounding the need for higher-speed interfaces for RapidIO serial interconnects. The key to effective deployment of these interconnects is maximizing the usable bandwidth of the channel; other interconnects require massive bandwidth over-provisioning, but with RapidIO full data bandwidth can be delivered robustly, with absolute repeatable low latency and low overhead.

VME: Which measures/specifications are being considered or have been recently ratified?

COX: Recently, the RapidIO Trade Association approved its 2.0 Specification, which adds links at 5.0 GB and 6.25 GB, with enhanced choices for widths including 1X, 2X, 4X, 8X, and 16X; extension of the RapidIO data and control plane functions to support large datagrams; VOQ (Virtual Output Queuing); more virtual channels; encapsulation of Ethernet; and other advanced data handling functions. Looking forward, we are considering link speeds to 12.5 GHz.

VME: VITA passed its Ex Ante patent policy last year, to reduce patent infringements and eliminate patent trolling. What measures is the RapidIO Trade Association taking to eliminate patent disclosure issues among members?

COX: RapidIO has always had a strong and well-proven patent disclosure policy, and like many of the industry standards groups, has not needed to change the measures that have been in place since its inception. RapidIO has a full RAND [Reasonable and Non-Discriminatory] process in place and follows ISO established disclosure. We are an internationally certified standards organization and have had no enforcement issues.

VME: There is a lot of industry buzz about the importance of interoperability between devices. Can you comment on how OEMs view this important milestone?

COX: Today, OEM systems are not built homogeneously with devices from only one semiconductor vendor. Therefore, ecosystems have evolved to ensure that everything a vendor needs to successfully design a product for a given application is available, beginning with a good selection of semiconductors. Implementing open standards is the first step to ensuring these devices work compatibly; however, it's not a guarantee.

OEMs tell us at RapidIO that repeatable interoperability testing by an independent lab is the key to fast prototyping, production, and time-to-market. In some cases, for example, where blades are used, it is not always possible to control which semiconductor manufacturers are going to be plugged in over time. So, OEMs are looking for interoperability testing that not only tests competing products, but ideally every device against all other devices. This thorough testing is the magic that can speed OEM time-to-market.

VME: RapidIO Trade Association members seem to be pursuing backplane applications in particular, and quite aggressively. Why is that?

COX: RapidIO technology is capable of delivering robust and reliable data at the full 10 GBaud rate. This makes it superior to all the other backplane choices. Ethernet requires 30 to 60 percent over-provisioning of the required throughput to compensate for the software stack and overhead. In RapidIO-based backplanes, the topology can be of any configuration; RapidIO technology supports multiple hosts, something PCI Express cannot do. In addition, RapidIO technology provides absolute, predictable latency.

VME: Will RapidIO eventually squeeze Ethernet out of the technology picture?

COX: It has never been the mission or goal of the RapidIO standard to displace or supersede any existing technology. RapidIO technology has strong embedded-focused features and capabilities. It was developed by the embedded market for the embedded market. RapidIO members are confident in saying that RapidIO will maintain strong value proposition for a future of generations of technology, indefinitely.

VME: What do you think will be the top three issues for your organization to address in the next five years?

COX: The key issues are to continue to build our technology on a platform that is fully backward compatible with past specifications, which we have done over the past six years. In addition, we will continue looking to the broad experience of our membership for innovation and best practices in order to deliver unprecedented advantages to the marketplace. As an association, the RapidIO Trade Association benefits from an ecosystem comprised of both the vendors and the customers driving embedded technology. Finally, we must foster a strong ecosystem that includes each of the critical components required for the most demanding applications in the embedded systems marketplace.

Tom Cox is executive director of the RapidIO Trade Association, where he is responsible for the association's future direction. Most recently, he was director of strategy at Tundra Semiconductor. Prior to that, he spent five years with IBM Microelectronics and was responsible for the PCI product line. He has held executive and engineering positions with ATI Technologies Inc., LSI Logic Corporation of Canada, Inc., Litton Systems Canada, and Philips Electronics Canada. He is a founding member of the PCI-SIG and has served in industry workgroups within PICMG, VITA, and NPF. He pursued advanced training in mathematics and electrical and computer engineering through the University of Southern California (USC), Humber College in Rexdale, and Mohawk College in Hamilton. He can be reached at

RapidIO Trade Association