This paper considers a wideband CDMA network with arbitrary but known layout and variable rate assignments, which is connected to a traditional wired IP network. We show that by using an optimization framework, it is possible to construct a distributed rate assignment algorithm similar to current congestion control protocols, which addresses both MAC and transport layer issues (i.e. interference and congestion control) simultaneously. We further show that, using the same optimization framework, it is possible to construct an overlay system at the MAC and transport layers which regulates rates separately based on the congestion and interference constraints. These rates are coordinated through the addition of an intermediate queue at each wireless source (i.e. MAC queue) and represent a cross- layer optimal solution. Finally, we show that both algorithms converge to the optimal rate assignment under static network conditions, and conduct simulation studies comparing the dynamic behavior of the two approaches.