With increasing availability of high-speed access links in the private sector, online real-time gaming has become a major and still growing segment in terms of market and network impact today. One of the most popular games is Unreal Tournament 2004, a fast-paced action game that still ranks within the top 10 of the most-played multiplayer Internet-games, according to GameSpy [1]. Besides high demands in terms of graphical computation, games like Unreal also impose hard requirements regarding network packet delay and jitter, for small deterioration in these conditions influences gameplay recognizably. To make matters worse, such games generate a very specific network traffic with strong requirements in terms of data delivery. In this paper, we analyze the network traffic characteristics of Unreal Tournament 2004. The experiments include different aspects like variation of map sizes, player count, player behavior as well as hardware and game-specific configuration. We show how different operating systems influence network behavior of the game. Our work gives a promising picture of how the specific real-time game behaves in terms of network impact and may be used as a basis e.g. for the development of specialized traffic generators.