  Losses of optical signals scale exponentially with the distance. Quantum
repeaters are devices that tackle these losses in quantum communication by
splitting the total distance into shorter parts. Today two types of quantum
repeaters are subject of research in the field of quantum information: Those
that use two-way communication and those that only use one-way communication.
Here we explain the details of the performance analysis for repeaters of the
second type. Furthermore we compare the two different schemes. Finally we show
how the performance analysis generalizes to large-scale quantum networks.
