A method is provided of transferring a data unit between a vehicle and an infrastructure communication network. The inter-vehicle communication network includes a plurality of roadside communication devices for relaying data to and from a vehicle traveling along a navigation route. At least a portion of the navigation route the vehicle is traversing is determined. The expected roadside communication devices disposed along the navigation route are identified. A respective time period that the vehicle will be within a transmitting range of each respective roadside communication device along the navigation route is estimated. The data message is segregated into sub-units of data. The amount of data contained in a respective sub-unit is based on an amount of data that may be communicated between the vehicle and a respective roadside communication device during the respective time period that the vehicle is within the transmitting range of the respective roadside communication device.