The Great Firewall of China still gives the best lesson on practical computer networking. Not only it teaches you the technical aspects but also the USA & Asia-Pacific ISP marketplace.

Telia, Cogentco, Level3, Hurricane Electric, Telstra, NTT, KDDI, Tata Communications, PCCW, HiNet.

Imagine studying the AS & peering using HE.net and BGP looking glass just to find a fast VPS vendor to browse the web.