A device and a method for communicating with a link partner device. The device may include a fragmentation unit configured to fragment a packet into multiple fragments if a size of the packet is greater than a maximum fragment size, a packet control header unit configured to generate a packet control header for a packet or each fragment of the packet, and a transceiver configured to send the packet or the fragments of the packet with the packet control header via a connection between the device and the link partner device. The packet control header may include at least one of a traffic control identifier field for identifying a data stream to which the packet belongs, a priority field for indicating a priority for the packet, or a data flow control field for congestion control between the device and the link partner device.