  Only little is publicly known about traffic in non-educational data centers.
Recent studies made some knowledge available, which gives us the opportunity to
create more realistic traffic models for data center research. We used this
knowledge to create the first publicly available traffic generator that
produces realistic traffic between hosts in data centers of arbitrary size. We
characterize traffic by using six probability distribution functions and
concentrate on the generation of traffic on flow-level. The distribution
functions are described as step functions, which makes our generator highly
configurable to generate traffic for different kinds of data centers. Moreover,
in data centers, traffic between hosts in the same rack and hosts in different
racks have different properties. We model this phenomenon, making our generated
traffic very realistic. We carefully evaluated our approach and conclude that
it reproduces these characteristics with high accuracy.
