Architectures with Bus‐Based Switch Fabrics: Case Study—DECNIS 500/600 Multiprotocol Bridge/Router

This chapter describes the architecture and implementation of the DECNIS 500/600 switch/route along with the main ideas that influenced the design of this family of switch/routers. The DECNIS 500/600 was designed to be flexible enough to support a wide range of Layer 2 and 3 functionalities while offering high forwarding performance. To achieve high packet forwarding performance, the DECNIS 500/600 employed a centralized forwarding engine assisted by distributed forwarding algorithms and buffer management mechanisms implemented on the line cards referred to as “in‐place packet forwarding”. The chapter includes a description of the in‐place packet forwarding processes in the line cards. It explains the four unicast processes that run on the receive side of a network interface card. The chapter then describes the unicast transmission functions of a network interface card. Finally, it discusses the transmission by a number of line cards for a packet buffer associated with Layer 3 multicasting and Layer 2 multicasting.