 be optionally appended to the classified packet for subsequent processing by a network processor or traffic manager. Results can comprise the following: One packet offset for regular expressions (or many offsets if subexpressions are used).. The number of rule(s) matched (again one or many if subexpressions are used). A packet ID. The classification results in a match that means one of the following: No rules were matched. Only one rule was matched. Multiple rules (or subexpressions) were matched. A rule was partially matched (cross-packet boundary assist). In this case, the current state is output as a result. It can be fed back into the classification processor as the next packet in this session through the look-aside interface, or it can be handed over through the cascade interface to another classification processor down the chain. Unlike other approaches by other classification processor vendors, no special description language needs to be learned. Regular expressions and subexpressions are used to create the rules in ASCII files using the company's graphical user interface (GUI)-based tool or any usual text editor. No packet offset is required and the processor can match an unanchored rule anywhere in the packet payload. Raqia's RegEx compiler parses the input, verifies the syntax, and identifies errors. It then compiles the authored rules into special tables that will compose the classification processor database. Besides parsing and compiling the rules input, the RegEx compiler also reports memory usage, which is 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. CLASSIFICATION PROCESSORS CLASSIFICATION PROCESSORS 259 extremely important when building a complete system. It must then be decided whether external rule memory is needed, and, if so, how much of it. The compiler is written in C+ + SO it easily enables independency of the dev