I've only listened to session 1, but I'm satisfied. A few years ago, when I was studying for my final exam, I first learned about the OSI 7-layer system. I remember memorizing it without understanding what it meant and just memorizing it. Until recently, I knew about the 7-layer system, but I didn't have a clear understanding of each layer. But now I understand it for the first time. It took a long time to study while searching and organizing the terms that were mentioned here and there, but I'm quite satisfied. I'm a first-year non-major developer, and I'm always envious of majors because I thought it was difficult even after reading CS books or lectures. But after taking this lecture, I realized that I can understand it too and that I should study harder. Thank you. 😍