A first device as a buffer server in an Ethernet transmits a first buffer client querying packet from a port of enabling a distributed buffer function of the first device, receives a first buffer client registering packet from a second device through the port, and adds the second device into a distributed buffer group of the port. When the first device detects that a sum of sizes of packets entering the port and not transmitted reaches a preset first flow-splitting threshold in a first preset time period, the first device forwards a packet entering the port and not transmitted to a buffer client selected from the distributed buffer group of the port.