The Unique Challenges of Testing Specialized Network-Based Data Acquisition Systems

The increasing speeds and decreasing prices of network equipment have spurred much interest in applying networks to many different types of systems. A wide range of network protocols and tools already exist making its application attractive. Over the last decade, there has been a noticeable shift to introduce Internet Protocol (IP) networks into new areas such as data acquisition systems. These modern network-based test systems are composed of a large number of recognizable devices such as switches, routers, and recorders. While these networks contain components familiar to most, common enterprise network test tools are not always sufficient to test these specialized systems. Typically, these specialized network-centric data systems require tighter timing accuracies, shorter latency windows, and little to no acceptable packet loss. The unique features of IP networks present testing challenges that must be addressed to provide reliable verification of the data acquisition system. Packet latency, delay, jitter, and loss are all factors that must be accounted for. Intentionally introducing these types of impairments to the data system are essential in any full, end-toend system test. It is not only important to produce these types of errors, but to mimic the conditions that will exist in the real system and reliably reproduce them at any time. This paper describes the shortcomings of those common network tools for testing specialized network-based data acquisition systems and the custom workarounds that were necessary to provide the test capabilities that we required. We will share some of our lessons learned from real-life examples of testing specialized network equipment for a flight-test data acquisition system that would apply to any network-centric data system. The paper will also describe a portion of our lab setup that allows us to rapidly reconfigure test networks and deploy custom simulation tools to support multiple types of data acquisition systems simultan- ously.