A method for transmitting a message from a first node device to a second node device in which the second node device belongs to network neighborhood of the first node device. The first and second node devices belong to an electrical supply network using powerline communications. The first node device begins by fragmenting the message into at least a first fragment and a second fragment. Next it associates a first frequency band of a set of frequency bands with the first fragment and a second frequency band with the second fragment, the first and second frequency bands being different. It then transmits each first and second fragment on the frequency band with which it is associated.