work processor, which has been designed for the OC-192c realm. The designers had the following critical requirements in mind when developing this product: ultrahigh per- formance, scalability, service breadth and awareness, multiple-protocol intelligence, and ease of pro- visioning for its customers. To properly focus the product design, the company correctly capitalized on the business impor- tance of supporting the incumbent carriers. These carriers have massively invested in legacy circuit- switched technologies such as time-division multiplexing (TDM) voice, SONET, frame relay, and Asynchronous Transfer Mode (ATM). However, they also want to provision newer IP-based services such as IPv4/v6, MPLS-based VPNs, and DiffServ, as well as incorporate CoS- and QoS-based traf- fic management and billing capabilities. The company was fully cognizant of the magnitude of this task, unlike other vendors who simply embark on an IP-packet-centric product development spree. It knew that the work would require a combination of a powerful network processor and a sophisticated traffic manager in order to handle this new environment. It also understood that its architecture should be able to offer computational capabilities that allow the real-time management of millions of 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. OTHER NPU ARCHITECTURES 142 NETWORK PROCESSORS microflow counts and hundreds of thousands of queue counts in addition to the associated classifica- tion and billing requirements that these numbers entail. Therefore, the designers took a fresh approach with the systems engineering and design of its first product-the Montego. They ensured a tight integration between the network processor and the traffic manager units within one and the same die. This resulted in a superchip that is impressively capable of providing five overriding types of f