This paper describes the performance benefits that can be realized from the utilization of multiple processing cores for communications applications. The paper illustrates the programming concepts of pipelining and flow-pinning in a packet-processing application and presents performance results from the use of these techniques on a popular open source intrusion detection application. Using a real-world network traffic scenario with a high number of TCP connections, the results show supra-linear (more than 6.2X) performance improvements when IP traffic flows are distributed among four cores versus running the same application on a single core.