Network processing is becoming an increasingly important paradigm as the Internet moves towards an architecture with more complex functionality inside the network. Modern routers not only forward packets, but also process headers and payloads to implement a variety of functions related to security, performance, and customization. It is important to get a detailed understanding of the workloads associated with this processing in order to be able to develop efficient network processing engines. We present a tool called PacketBench, which provides a framework for implementing network processing applications and obtaining an extensive set of workload characteristics. PacketBench provides the support functions to handle various packet traces and manage packet memory. For statistics collection, PacketBench provides the ability to derive a number of microarchitectural and networking related metrics. The understanding of workload details of network processing has many practical applications. As network processing systems move towards highly parallel embedded systems, it is becoming increasingly important to explore the processing requirements of individual packets rather than averaged statistics. We show a range of workload results that focus on individual packets and the variation between them