Tsinghua University publishing house, synchronous training for network engineers, 44 yuan.

In addition, it depends on your own situation. It should be noted that the course does not include all the contents of the exam, such as computer hardware and software engineering, so you must buy some other books, and of course you can borrow them from the library. Personally, I think Xie Xiren, the 4th Edition of Computer Network, is a book worth reading.

The registration fee is generally around 120 yuan, and three months should be enough. Registration will be made in March in the first half of the year and in 10 in the second half of the year.

As for the learning methods, I think it's best to download some videos, such as Sisai and Sadie's, which are all very good. Of course, there may be many that you can't find online. I have a lot here. I can send it to you if necessary. What's more, you can look at the computer network (research) of Shanghai Jiaotong University at first, in the whiteness video. You can ask me directly if you have any questions.