Broadcast networks are potential for carrying services with both high data rate and high mobility. Combined with other media as return channels for user requests and acknowledgment signaling, broadcast networks can provide interactive data services too. This paper proposes a multichannel architecture for Integrated Communication and Broadcast Networks (ICBN) which employs all redundant available broadcast bandwidth to provide huge access bandwidth for multimedia information delivery while in fast moving. This architecture can be a highly recommendable candidate of future 4G/5G communications. Most existing bandwidth management policies focus on single channel bandwidth distribution over different data flows, and no multichannel bandwidth management policies for ICBN are found yet. In order to fully employ all channels, a Profit Oriented Bandwidth Allocation Method (POBAM) is given for real-time multichannel bandwidth management. Analytical and simulation results show that the POBAM can exploit the multichannel resources for near global profit maximization, and provide effective QoS differentiation as well. In addition, the joint channel management outperforms the separate channel management greatly. The complexity of the POBAM is low enough for on-line multichannel bandwidth management even when the scale of ICBN is quite large.