For many enterprises, upgrading a network used to be an exercise in meeting the increased bandwidth needs of users. First, it was transitioning from bus-based shared networks to switched Ethernet, and after that from switched Ethernet to switched Fast Ethernet. But as companies now entertain the prospect of transitioning to Gigabit Ethernet networks it’s not to meet pressing bandwidth needs. This time, it’s to build a network infrastructure that can deliver increasingly-sophisticated network services and intelligence to end users. Generally, that means creeping up the protocol stack into the upper layers.

This paper will explore the evolution of networking system designs to meet these trends, focusing on board-level interconnect. Interconnect represents the last bottleneck in a board design because traditional daisy-chain and bus-based interconnects limit flexibility and can have high latency and throughput that is impacted by bus contention and speed limitations. Switch-based interconnect architectures are becoming increasingly popular in Gigabit-speed designs to support the increased performance and data flow complexity.