Overview

In theory there is no difference between theory and practice. In practice there is.
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This book is going to show you the practical side of programming the 12xx series of Intel s Internet eXchange network Processors (IXP). Much has been written about network processors in the last few years. Perhaps too much, because nowadays defining the term network processor involves writing a dissertation. So while network processor definitions are different, the motivations for using network processors are similar. Ostensibly, network processors enable you to add, through software, the latest-and-greatest network service while maintaining high packet throughput and low packet latency. Of course, since we are talking about services delivered via software, as opposed to through hardware such as Application Specific Integrated Circuits (ASICs), we should be able to get these latest-and-greatest network services out faster, right? Well, in theory, maybe.

In practice, the time-to-market advantages provided by implementing a new network service in software on a network processor can be offset by the steep learning curve for programmers of the network processor. The new tools, languages, and programming environments used to help network processors achieve their high performance can quickly humble even the most experienced programmer. The IXP12xx processor is no exception.

The IXP12xx processor offers a wide range of programmability through hardware units and co-processors specifically tuned to network programming, in addition to a general-purpose core processor. Due to this specialization, the IXP12xx can provide flexible programmability without sacrificing performance as might be expected with generalpurpose processors.