Technologies and building blocks for fast packet forwarding

We provide a review of the state of the art and the future of packet proces sing and switching. The industry's response to the need for wire-speed pack et processing devices whose function can be rapidly adapted to continuously changing standards and customer requirements is the concept of special pro grammable network processors. We discuss the prerequisites of processing te ns to hundreds of millions of packets per second and indicate ways to achie ve scalability through parallel packet processing. Tomorrow's switch fabric s, which Will provide node-internal connectivity between the input and outp ut ports of a router or switch, will have to sustain terabit-per-second thr oughput.,After reviewing fundamental switching concepts, we discuss archite ctural and design issues that must be addressed to allow the evolution of p acket switch fabrics to terabit-per-second throughput performance.