n channels and the awesome speed of the transmission of digital data over these fiber-optic links would enable the extraordinary new capabilities that we have come to see in the infrastructure net- works. These new broadband networks require equipment with remarkable computing power and intelligence in order to be able to process transmitted and received data at both ends of an optical link 33. Peter Tomsu and Gerhard Wieser, MPLS-Based VPNs: Designing Advanced Virtual Networks (Upper Saddle River, New Jersey: Prentice-Hall, 2002). 34. Ivan P. Kaminow and Thomas L. Koch, eds., Optical Fiber Telecommunications IIIA (New York: Academic Press, 1997). 35. Govind P. Agrawal, Fiber-Optic Communication Systems, Wiley Series in Microwave and Optical Engineering (New York: John Wiley, 1997). 36. Rajiv Ramaswami and Kumar Sivarajan, Optical Networks: A Practical Perspective, 2nd ed. (San Francisco: Morgan Kaufmann Publishers, 2001). Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. THE EVOLUTION OF NETWORK TECHNOLOGY: DISTRIBUTED COMPUTING AND THE CONVERGENCE OF NETWORKS 20 NETWORK PROCESSORS and at line speeds. 37 Therefore, from another point of view, we see the need for powerful network processors inside communications equipment. Until this processing is handled completely with optical technologies, fast microelectronics will play a key role; therefore, network processors enable this type of functionality at very high speeds of transmission. PROCESSORS: RISC, DIGITAL SIGNAL PROCESSOR (DSP), AND INTEGRATION TOWARD SYSTEM-ON-A-CHIP (SOC) Microprocessors were available in the 1970s, but they were simple 4- and 8-bit processors of small to medium levels of silicon integration. Given the very limited levels of integration of silicon that semiconductor technology allowed at that time, high-performance computers were based on complete CPU modules. These mod