  We study the extent to which decentralized cost-sharing protocols can achieve
good price of anarchy (PoA) bounds in network cost-sharing games with $n$
agents. We focus on the model of resource-aware protocols, where the designer
has prior access to the network structure and can also increase the total cost
of an edge(overcharging), and we study classes of games with concave or convex
cost functions. We first consider concave cost functions and our main result is
a cost-sharing protocol for symmetric games on directed acyclic graphs that
achieves a PoA of $2+\varepsilon$ for some arbitrary small positive
$\varepsilon$, which improves to $1+\varepsilon$ for games with at least two
players. We also achieve a PoA of 1 for series-parallel graphs and show that no
protocol can achieve a PoA better than $\Omega(\sqrt{n})$ for multicast games.
We then also consider convex cost functions and prove analogous results for
series-parallel networks and multicast games, as well as a lower bound of
$\Omega(n)$ for the PoA on directed acyclic graphs without the use of
overcharging.
