A method and system for wireless communication between a moving vehicle, such as a train, and a remote server through at least one external mobile network are disclosed. The communication system includes at least one router in the train for receiving and transmitting wireless data communication to and from a stationary communication server outside the train through at least one exterior mobile network via at least one antenna. The router includes a control unit configured to allocate bandwidth according to a predefined packet policy to streams of data packets which are matched to the predefined packet policies, providing for a very efficient bandwidth management in a wireless network within a train. Hereby, is easy to prioritize voice-over-IP (VOIP) and/or VPN traffic over video traffic.