Adaptive Physical Transmission Mode Selection

A data transmission network comprises two groups of nodes ( 1; 2, 3, 4 ), a radio interface associated to each group and connected to the nodes ( 1 ) of the group and a radio path ( 5 ) between the two radio interfaces ( 9 ), in which several groups ( 14 12 , 14 13 , 14 14) of virtual paths ( 15 ) of warranted bandwidth are transmitted between one node ( 1 ) of the first group and one node ( 2, 3, 4 ) of the second group. The sum of the bandwidths warranted to the groups ( 14 12 , 14 13 , 14 14) of virtual paths does not exceed the total bandwidth of the radio path ( 5 ) when operated in a transmission mode referred to as basic mode. The radio interfaces ( 9 ) support several physical transmission modes of different bandwidths and are adapted to detect the transmission quality of the radio path ( 5 ) and to operate, the transmission quality of the radio path ( 5 ) permitting, the radio path ( 5 ) in a transmission mode of higher bandwidth than that of the basic mode and to use the bandwidth difference between the used mode and the basic mode for bandwidth need of the groups of virtual paths in excess of the warranted bandwidth.