A router (14) for use in a communication network (10) and an associated method. The router (14) includes input ports each having an associated input buffer for receiving data packets from a sending device and output ports for sending data packets to a receiving device. The router (14) also includes a means to direct data packets from the or each input port to one or more of the output ports and a means for providing information to each sending device such that a determination may be made as to whether or not the sending device may transmit packets in order to assure lossless transfer. The means to direct data packets from a particular input port includes a method of control in order to regulate the transfer of data packets, where this regulation is based on a count of the data packets previously transferred from that input port and not yet output from the output port. The router (14) transmits data packets from the output port only when loss free transfer to the input port of the receiving router (14) is assured.