You can see what the "Internet" is from beginning to end with your own eyes. Even if you are not an IT professional, it would be really good to see it as general knowledge. When studying the physical (device) contents of the network in a book, I just thought it was like that and moved on, and it disappeared from my memory or remained as magic. (If the Internet doesn't work, I immediately call the telecommunications company's AS haha) But....you can see all of this in animation. Seeing how data flows directly from cables, switches, and routers in real time, I think I really understood the abstract (magic) parts or fragmented knowledge. The best lecture was [What happens when you search Google?] I wish someone would make a video (moving) of the beginning to the end of telecommunications and I was finally able to see how it crosses the ocean.ㅠㅠ The latter half of the topics (L4 ~ L7) will be directly helpful to those preparing for the backend. Thank you so much for the lecture, Mr. Potato! If you make the next lecture, I'm curious to know what the topic will be~