LwIP is widely used as a lightweight network protocol stack in embedded devices.This article studies the internal data management methods of the LwIP protocol stack in order to better apply and develop new protocol stacks.Firstly,introduce the data storage method of the LwIP protocol stack and compare it with the FreeRTOS storage method;Then,in response to the data packet fragmentation problem caused by different transmission capabilities of network devices,explore the data management methods used to form a complete data packet using the LwIP protocol stack;Finally,study the software design approach of the LwIP protocol stack at the TCP layer.