Internet

A “network of networks”.

The Internet today is based on a “best-effort” paradigm

… and regional networks may arise to connect access nets to ISPs.

… and content provider networks (e.g., Google, Microsoft, Akamai) may run their own network, to bring services, content close to end users.

At “center”: small # of well-connected large networks

• “tier-1” commercial ISPs (e.g., Level 3, Sprint, AT&T, NTT), national & international coverage
• content provider networks (e.g., Google, Facebook): private network that connects their data centers to Internet, often bypassing tier-1, regional ISPs