The Internet has established itself as a worldwide communications medium for a broad spectrum of communication modes: data, voice, and video—both asynchronously and in real time. Its growing popularity for entirely new applications in the field of e-business and entertainment, as well as its emerging use for well established applications such as telephony, have resulted in a spectacular annual growth factor of at least 4 (and rising [1]) for traffic carried by the net. The Internet is able to grow at this enormous pace because of the exponential growth of optical transmission bandwidth made possible by wavelength division multiplexing (WDM) and commensurate progress in the packet-forwarding capabilities of network nodes (routers and switches).. Early routers, the workhorses of Internet traffic forwarding, were based on computer-like architectures in which line cards were connected via buses to main memory, the CPU, and one another. Packet data had to flow at least twice (if not more) over the system bus, creating a severe bottleneck.