Tier 1 Networks
The internet has no central authority, but it does have a core. Roughly a dozen networks sit at the absolute top of the routing hierarchy, exchanging traffic for free.
The Settlement-Free Peering Club
A "Tier 1" network is defined by one strict rule: they do not pay anyone for transit. They can reach every other network on the internet purely through settlement-free peering with other Tier 1s, or by selling transit to downstream customers (Tier 2 and Tier 3 networks).
| ASN | Network Operator | Estimated Route Origins | Notes |
|---|---|---|---|
| AS3356 | Lumen (formerly Level 3) | Highest degree of connectivity globally. | The undisputed largest backbone provider. |
| AS1299 | Arelion (formerly Telia) | Dominant in Europe and Trans-Atlantic. | Major player in submarine cable ownership. |
| AS2914 | NTT Communications | Dominant in Asia-Pacific. | Heavy investor in trans-pacific submarine cables. |
| AS7018 | AT&T | Legacy US monopoly footprint. | Rarely peers openly, heavily restrictive peering policies. |
| AS6453 | Tata Communications | Global reach, dominant in India. | Operates the TGN cable network. |
The De-Peering Wars
Because Tier 1 status is based on mutual business agreements rather than technical standards, relationships occasionally break down. When two Tier 1 networks argue over traffic ratios (e.g., Network A is sending 10x more traffic to Network B than it receives) they may "de-peer" or sever their BGP connections.
This causes immediate routing fragmentation. If AS3356 de-peers with AS1299, their respective single-homed customers can no longer communicate with each other, effectively splitting the internet until the dispute is resolved.
Are Hyperscalers Tier 1?
Google (AS15169), Meta (AS32934), and AWS (AS16509) generate more traffic than traditional Tier 1s. However, they are technically "content networks," not transit networks. They peer heavily, but they do not provide full transit routing to third parties.
Tool: Peering Ratio Analyzer
Calculate peering traffic ratios to see if a connection violates standard settlement-free peering policies.
Common Mistakes
- Confusing Tier 1 with quality: Just because AT&T is a Tier 1 doesn't mean it provides the lowest latency to an end user. A localized Tier 2 network connected directly to a local data center will often outperform a Tier 1 routing traffic out of state.
- Assuming "free" means no cost: Settlement-free peering means no money exchanges hands for traffic, but both parties still have to pay for the physical cross-connects and router ports at the exchange.
FAQ
Can a new network become a Tier 1?
Practically, no. The existing Tier 1 networks have no financial incentive to let a new competitor peer for free. They will strictly enforce peering requirements (minimum geographic footprints, traffic minimums) that are impossible for a new entrant to meet without first buying transit from them.