1. If you have studied networks, you will know that the concept of networks is not well understood and there are many times when you do not understand it clearly. The lecture explains the reason and proceeds with the class so that you can understand it properly. 2. You can understand networks from two perspectives: infrastructure and programmer. 3. The lecture is not conducted with a prepared PPT, but rather, it is explained by drawing pictures while conducting the class, so it is much easier to understand. 4. You can review whether you understood it correctly by drawing what you understood and comparing it with the instructor's picture.