  As quantum key distribution becomes increasingly practical, questions of how
to effectively employ it in large-scale networks and over large distances
becomes increasingly important. To that end, in this work, we model the
performance of the E91 entanglement based QKD protocol when operating in a
network consisting of both quantum repeaters and trusted nodes. We propose a
number of routing protocols for this network and compare their performance
under different usage scenarios. Through our modeling, we investigate optimal
placement and number of trusted nodes versus repeaters depending on device
performance (e.g., quality of the repeater's measurement devices). Along the
way we discover interesting lessons determining what are the important physical
aspects to improve for upcoming quantum networks in order to improve secure
communication rates.
