Communication Profile

RapidIO Interconnect

Domain(s)

Space

System(s)

Satellite

Profile(s)

COMM

RapidIO technology is a packetized point-to-point interconnect fabric. Packets carry user-definable payloads from 1 to 256 bytes. Both serial and parallel physical interfaces are defined, allowing effective data rates from 667 Mbps to 30 Gbps. The serial version of RapidIO was chosen for JAS because it requires a small number of connecting wires between nodes.

RapidIO systems are comprised of end point processing elements and switch processing elements. The RapidIO interconnect architecture is partitioned into a layered hierarchy of specifications which includes the Logical, Transport, and Physical Layers. Switches in RapidIO are synonymous with routers in SpaceWire.

RapidIO Network

The Rapid IO specification is divided into 14 volumes. Each volume fits within one of four groups: the logical layer, the transport layer, the physical layer, and a special topics group. The breakdown is as follows:

Logical Layer

Part 1 – Logical I/O Specification

Part 2 – Message Specification

Part 5 – Global Shared Memory Specification

Part 9 – Flow Control Specification

Part 10 – Data Streaming Specification

Transport Layer

Part 3 – Transport Specification

Part 11 – Multicast Specification

Physical Layer

Part 4 – Parallel Physical Specification

Part 6 – Serial Physical Specification

Part 12 – Virtual Output Queueing Extensions Specification

Special Topics

Annex I – Software/System Bring-up Specification

Annex II – Session Management Protocol Specification

Part 7 – System and Device Inter-operability Specification

Part 8 – Error Management/Hot Swap Extensions Specification

RapidIO packets are formed through the combination of bit fields defined in each of the layers. The figure below shows the format of a RapidIO packet. Each layer represents a different layer of the specification. The MTU size of a RapidIO packet is 280 bytes, of which up to 256 bytes are user-definable data.

RapidIO Packet