A packet processing method in a hybrid access network, implemented by a first network device, the method comprising: sending data packets in a first sending window to a second network device via a first tunnel between the first network device and the second network device; based on an acknowledgement response from the second network device, adjusting a size of the first sending window; in response to the size of the first sending window being greater than or equal to a first threshold, sending subsequent received data packets in a second sending window to the second network device via a second tunnel between the first network device and the second network device, wherein the data packets comprise a first data packet, wherein the first data packet comprises a first sub-link number representing a sequence number of the first data packet in the first tunnel, and the adjusting the size of the first sending window is characterized by: in response to receiving the acknowledgement response, increasing the size of the first sending window based on a first proportion, wherein the acknowledgement response comprises an acknowledgement number obtained based on the first sub-link number; and in response to not receiving, within a first time, the acknowledgement response, decreasing the size of the first sending window based on a second proportion, wherein the second proportion is greater than the first proportion. sending data packets in a first sending window to a second network device via a first tunnel between the first network device and the second network device; based on an acknowledgement response from the second network device, adjusting a size of the first sending window; in response to the size of the first sending window being greater than or equal to a first threshold, sending subsequent received data packets in a second sending window to the second network device via a second tunnel between the first network device and the second network device, wherein the data packets comprise a first data packet, wherein the first data packet comprises a first sub-link number representing a sequence number of the first data packet in the first tunnel, and the adjusting the size of the first sending window is characterized by: in response to receiving the acknowledgement response, increasing the size of the first sending window based on a first proportion, wherein the acknowledgement response comprises an acknowledgement number obtained based on the first sub-link number; and in response to not receiving, within a first time, the acknowledgement response, decreasing the size of the first sending window based on a second proportion, wherein the second proportion is greater than the first proportion. in response to receiving the acknowledgement response, increasing the size of the first sending window based on a first proportion, wherein the acknowledgement response comprises an acknowledgement number obtained based on the first sub-link number; and in response to not receiving, within a first time, the acknowledgement response, decreasing the size of the first sending window based on a second proportion, wherein the second proportion is greater than the first proportion.