RplTrc: A Tool for Emulating Real Network Dynamics for Performance Evaluation

Evaluating the performance of distributed applications, such as mobile telephone or video conferencing devices, has become increasingly complex as the diversity of scenarios and data rates in networks increase. In this paper, we present the design and implementation of RplTrc, a network emulation tool. RplTrc uses traces to drive interceptions of the Linux protocol stack to delay, drop or duplicate packets. The length of traces is not limited. Thus, unlike other well-known emulators such as NIST Net or the emulator module in the Linux 2.6 kernel, RplTrc is capable to account for important performance characteristics inherent to real networks such as long-range dependence and self-similarity of cross-traffic. Tests show that RplTrc installed on a commodity PC is capable to emulate a 100MBit/s or a lightly-loaded 1GBit/s network and has a precision in reproducing packet delays in the order of 100 mus. RplTrc thus enables extensive performance evaluation of distributed applications in lab environments.