Overview

Theory can leave questions unanswered, but practice has to come up with something.
Mason Cooley

Whether you are looking to use the IXP2XXX series of Intel s network processors to build a modest single-box switch or a fully redundant, multi-blade, content-aware, packet processing system, this book is your programming guide. The IXP2XXX processors offer a wide range of programmability through programmable processors and coprocessors specifically tuned to network programming. Due to this specialization, the IXP2XXX processors can provide flexible programmability without sacrificing performance as might be expected with general-purpose processors. ^[1]

At the same time, the new programming model presented by any network processor, including the IXP2XXX processor, can be daunting. For example, say you want to write a network address translation (NAT) function for the IXP2800, which has seventeen programmable processors and at least four different types of memory. How many, and which, processors would you devote to performing the NAT function? Which memory would you use to hold your data structures, and how would you best organize your data structures? For answers to these questions, keep reading!

As you begin programming the IXP2XXX processor, accomplishing seemingly trivial tasks, such as receiving or transmitting packets, has been known to invoke an all-out engineer s victory dance. This initial programming experience can be especially frustrating for programmers already well versed in the standard write-debug-optimize programming methods. Optimizing code is less about finding ways to execute fewer lines of code and more about understanding ways to offload work to the hardware.