 system by cleverly adopting pipelining and multithreading functionality that is available inside the network processor. Turning the argument the other way, the most astounding (and most expen- sive) CAM component may not be necessarily needed in order to meet system search performance requirements. If the NPU architecture and software development toolset allow the tinkering of func- 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. SEARCH ENGINES SEARCH ENGINES ACL-QoS-Billing Maximum packets rate per second (in millions) RMON & Layer-3 Forwarding ACL-QoS-RMON & Layer-3 Forwarding ACL-QoS and Layer-3 Forwarding ACL & Layer-3 Forwarding Layer-3 forwarding OC-12 OC-48 10GbE OC-192 OC-768 FIGURE 12.4 The interrelationship between typical applications, packet rate, wire speed, and the esti- mated need for search capabilities. (Source: IDT) tionalities such as the creative and efficient allocation of computational load on multiple engines, stages on a pipeline, or threads running concurrently, then the systems designer suddenly has more freedom. To get an idea of the technology evolution and where the search engine industry is headed, refer to Figure 12.4. In this figure, the interrelationship is shown between wire speeds, packet arrival rates, typical application loads involving a spectrum of cases spanning from simple Internet Protocol (IP) routing and access control lists (ACLs) all the way to consolidated environments with QoS provi- sioning, per-use billing, even network management using Remote Monitoring (RMON), and the com- mensurate number of searches needed per packet. In order to meet carrier-class requirements for QoS and service level agreements (SLAs), the expected classification performance for OC-768 (40 Gbps) layers 4 to 7 applications will usually require a search performance of at least 125 Msps speeds and sophisticated classific