RapidIO: The Next Generation Communication Fabric For Embedded Application

Chapter 11. Advanced Features

The RapidIO specification supports several optional advanced features. These features would not be required in all systems or applications of RapidIO. This chapter will present details on the following optional RapidIO features:

• system-level flow control

• error management

• multiprocessor cache coherence

• multicasting transactions

• multicasting symbols

The RapidIO architecture was defined to support optional functionality in a compatible manner. The basis for this compatibility can be found in the separation of responsibility between RapidIO end point and RapidIO switches. End points are responsible for creating and terminating packets. Switches are responsible for forwarding packets towards their final destination. New or optional transaction types must be understood between source and destination, but do not need to be understood by switches. The three optional features described in this chapter offer new logical layer transactions that existing switches will transparently forward through a system. So long as the transactions retain the physical and transport layer header structure they will be compatible with existing RapidIO switch infrastructure.

System-level flow control is an optional feature that would be used in larger-scale systems where traffic patterns might create short-term congestion in the system. The RapidIO link-level flow control is useful for preventing buffer overruns between two adjacent RapidIO devices; the system-level flow control ...