Routing Packets with Light; January 2001; Scientific American Magazine; by Daniel J. Blumenthal; 4 Page(s)

Today's network architects have already begun to build the Optical Internet using technologies that can switch some or all of the light signals in one incoming optical fiber to one or several outgoing fibers. The new-generation Optical Internet will serve as a highspeed mail delivery vehicle that will bring units of data called packets to a point nearby a recipient. There the time-consuming process of sorting out which packet goes where-the Internet equivalent of the local post office-will fall to electronic routers from companies such as Cisco Systems and Juniper Networks. Over time, even this task of switching individual packets may be taken over by routers that use photons, not electrons, for processing.

The IP packet is the Internet's basic unit of currency. In today's networks, every e-mail message gets chopped into thousands of packets, which are switched over different pathways and reassembled at a final destination using the Internet Protocol (IP). The routers, together with other networking equipment, convert data from lightwaves to electronic signals in order to read the packets and send them along to their final destination: a mail server, where they are reassembled into a coherent message before a synthesized voice proclaims, "You've got mail!" The key is that the routers all along the way can easily read the address of each IP packet.