  Network Creation Games(NCGs) model the creation of decentralized
communication networks like the Internet. In such games strategic agents
corresponding to network nodes selfishly decide with whom to connect to
optimize some objective function. Past research intensively analyzed models
where the agents strive for a central position in the network. This models
agents optimizing the network for low-latency applications like VoIP. However,
with today's abundance of streaming services it is important to ensure that the
created network can satisfy the increased bandwidth demand. To the best of our
knowledge, this natural problem of the decentralized strategic creation of
networks with sufficient bandwidth has not yet been studied.
  We introduce Flow-Based NCGs where the selfish agents focus on bandwidth
instead of latency. In essence, budget-constrained agents create network links
to maximize their minimum or average network flow value to all other network
nodes. Equivalently, this can also be understood as agents who create links to
increase their connectivity and thus also the robustness of the network. For
this novel type of NCG we prove that pure Nash equilibria exist, we give a
simple algorithm for computing optimal networks, we show that the Price of
Stability is 1 and we prove an (almost) tight bound of 2 on the Price of
Anarchy. Last but not least, we show that our models do not admit a potential
function.
