I like the design, but I'm unsure who the target audience is. If it's target at complete beginners, it's a bit of a rough start, I think. In the first chapter, it explains how tcp is different from ip and udp, and only later explains what udp is. Also, why would a beginner care?
The valley of websites, anyway. I don't know when I started feeling this way, but I get emotionally exhausted seeing the two conflated.