An Empirical Study of NetEm Network Emulation Functionalities

In this paper we have evaluated the main functionalities of NetEm, a popular Linux based network emulator, which we have used to stress test the performance of the Games@Large distributed gaming system. We have performed a number of tests on different NetEm functionalities in order to evaluate their practical performance conformity and validity versus the NetEm description and theoretical expectations. We have found that the NetEm behaviour conforms to expectations for the emulation of delay and packet loss without correlation. However, in the case of jitter emulation, the actual realized jitter is lower than the given input value. It is an important fact to be aware of when using NetEm for different application testing. This paper also provides a baseline methodology for network emulation tool validation.