y from a competent and qualified third party. This core circuitry delivers the desired functionality, and has been designed, tested, and documented according 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. ALTERNATIVE APPROACHES TO NETWORK PROCESSING: NET ASICS AND DESIGNING WITH IP CORES 162 NETWORK PROCESSORS to specific methodologies and industry-accepted criteria, thereby offering the possibility of con- nectivity and programmability as well as easy integration into a larger design, testability, documen- tation, and even scalability of performance. These characteristics can be combined with the inevitable accelerated time obtained by having to design less of the final product. The decision almost seems to favor using IP cores. One of the advantages companies see in using licensing IP cores (or even internally generating their own cores) is that it promulgates a school of thought that believes in the merits of component reuse. Following the same evolution path that was taken by systems implemented on printed circuit boards (PCBs) in the late 1970s and early 1980s when large-scale integration (LSI) and medium-scale integration (MSI) components started replacing the discrete use of multiple transistors in the imple- mentation of more sophisticated systems, designs of complete systems-on-a-chip (SOC) are now based on the structured use (and even reuse) of multiple cores that implement several functions. Ample literature has been written on the subject of designing and verifying IP cores as well as on the methodologies involved in the reuse of hardware and software IP components. Interested readers should refer to several of the pertinent sources in the section "Suggested References" provided at the end of the chapter. In the context of network processing, the IP core principle is applied to computational resources that facilitate, if not acc