RapidIO: The Next Generation Communication Fabric For Embedded Application

14.4. IMPLEMENTING A RAPIDIO SWITCH

This section describes how the RapidIO protocol can be implemented in a parallel or serial RapidIO switch. A switch's primary responsibility is routing packets across a RapidIO system from the source to the destination using information contained in the packet header. Switches do not modify the logical or transport layers of the packet; only the physical layer contained within the packet is modified at each link. Switches determine the network topology and are an integral part of overall system performance.

14.4.1. Switch Features

RapidIO is a packet-based protocol. Implementations of packet switching functions have been developed and designed for years. Packet switch architectures and design considerations are well understood. Generally, a switch first treats an incoming packet from a physical layer point of view; it deals with low-level aspects of link management, physical error conditions, buffer availability and other physical considerations. The switch then executes the routing function, as would any other packet-based protocol such as ATM or Ethernet.

As described in the RapidIO specification, each interface on a RapidIO switch must process both inbound and outbound transactions at the same time. The inbound and outbound modules of each interface can be designed as logically separate blocks or as a single block. Communication between the inbound and outbound ports in the physical and transport layers of RapidIO is easily supported with ...