(Nowadays, there are many network applications, such as BT, eDonkey, Thunder, FTP, online video, etc., all occupy a lot of bandwidth. Take an Internet cafe with 200 solutions as an example, the export bandwidth is 10M, and the average bandwidth of each internal PC is about 50K. If A few people are downloading frantically, and the bandwidth is occupied, which will affect the network speed of others. Others are downloading large files. The maximum IP packet can reach 1518 BYTE, which is 1.5k.)