Data link layer device and packet encapsulation method thereof

A packet encapsulation method for a data link layer device, comprising:

• when a first first-in-first-out (FIFO) module is empty, receiving, by the first FIFO module, a plurality of first data from an upper-layer module, and removing a data gap from the first data such that the first FIFO module stores the first data in a continuous form;
• determining, by the first FIFO module, whether a data queue of a second FIFO module is empty;
• when the data queue of the second FIFO module is not empty, determining, by the first FIFO module, whether a number of a used to-be-sent layer in a header queue of the second FIFO module is greater than or equal to a critical value;
• when the number of the used to-be-sent layer is greater than or equal to the critical value, after finishing waiting for the header queue to perform data transmission, determining again, by the first FIFO module, whether the number of the used to-be-sent layer is greater than or equal to the critical value;
• and
• when the number of the used to-be-sent layer is smaller than the critical value, generating, by the first FIFO module, data of different lengths based on a current amount of data stored temporarily in the first FIFO module and a data length that has been set, and transferring, by the first FIFO module, a header comprising the data length to the header queue of the second FIFO module.