In a method for the insertion of information to synchronize a destination node with a data stream transmitted from an entry terminal in a heterogeneous network, the heterogeneous network includes at least one sub-network conveying first packets and one basic network conveying second packets. The entry terminal is connected to the sub-network. The sub-network is connected to the basic network by means of an entry terminal forming the second packets from at least one sub-part of at least one first packet. At the occurrence of at least one pre-determined event, the entry node: forms a second synchronization packet such that the beginning of the useful information of the second synchronization packet corresponds to the beginning of a first packet; inserts a synchronization marker in the second synchronization packet; and modifies the size of a second packet preceding the second synchronization packet.