1. Tier-1 ISP 定义：

- A Regional Tier 1 ISP is an ISP that has access to the entire Internet Region solely via its free and reciprocal peering agreements, and it doesn't paytransit fees to anyone to reach any destination in the Internet Region。

 

    Tier-1 ISP是这样一种ISP，它们可以访问互联网的任意角落，而不需要向任何人/单位缴纳任何费用。它们构成了互联网的骨干。一般负责国家级之间进行互连的ISP都是 Tier-1 ISP.

    这些Tier-1 ISP 合在一起，被称为 "Tier-1 Club" 。

   

    在中国，中国电信和中国网通/联通是 Tier-1 ISP.

2. Tier-2 ISP 定义:

- Tier-2 ISP is an Internet service provider who engages in the practice of peering with other networks, but who still purchases IP transit to reach some portion of the Internet.A tier-2 ISP is a customer of one or more tier-1 ISP.

Tier-2 ISP 可以建立自己的网络以便和其它网络互连并构成Internet的一部分，但是它们还必须向Tier-1 ISP 付费以便访问互联网的其它一些区域。

   在中国，比如教育网、中国移动等属于 Tier-2 ISP。 它们有自己的网络，但是又需要支付一定的费用以便访问互联网的其它区域。

3. Tier-3 ISP

    - A networks or ISP who solely purchase IP transit from other networks (typically Tier 2 networks) to reach the Internet.

    它们完全购买流量以访问互联网。

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附录： Tier-1 ISP列表

The U.S. Internet Region Tier 1 ISPs

In the U.S. the Tier 1 ISPs (aka "The Tier 1 Club") are:

1. AT&T
2. Verizon
3. Sprint
4. Century Link (Qwest)
5. Level 3
6. NTT/Verio
7. Global Crossing
8. Cogent (maybe?)

The Singapore Internet Region Tier 1 ISPs

In Singapore the Tier 1 ISPs (aka "The Holy Trinity") are:

1. SingTel
2. StarHub
3. Pacific Internet

The Japan Internet Region Tier 1 ISPs

In Japan the Tier 1 ISPs are:

1. NTT
2. Softbank Broadband (Japan Telecom)
3. KDDI
4. IIJ
5. Powered.com

The Hong Kong Internet Region Tier 1 ISPs

In Hong Kong the Tier 1 ISPs are:

1. PCCW
2. PacNet (Asia Netcom)
3. HKTelecom
4. Reach **

The Australian Internet Region Tier 1 ISPs

In Australia the Tier 1 ISPs (aka "The Gang of Four") are

1. Telstra
2. Optus (SingTel)
3. OzeMail (Verizon)
4. Connect.com (Telecom New Zealand)

The New Zealand Internet Region Tier 1 ISPs

In New Zealand the Tier 1 ISPs are

1. Telecom New Zealand
2. Telstra Clear

The China Internet Region Tier 1 ISPs

In China the Tier 1 ISPs are

1. China Telecom
2. China Unicom (China Netcom)

The Holland Internet Region Tier 1 ISPs

In Holland the Tier 1 ISP is

1. KPN

In the U.K. the Tier 1 ISP is

The U.K Internet Region Tier 1 ISPs

1. British Telecom

The Swedish Internet Region Tier 1 ISPs

In Sweden the Tier 1 ISP is

1. TeliaSonera

The Finnish Internet Region Tier 1 ISPs

In Finland the Tier 1 ISP is

1. TeliaSonera

The Turkish Internet Region Tier 1 ISPs

In Turkey the Tier 1 ISPs are

1. Turkish Telecom
2. Super Online
3. Smile ADSL

The Indian Internet Region Tier 1 ISPs

In India the Tier 1 ISPs are

1. Bharti
2. Reliance
3. Tata
4. VSNL

The German Internet Region Tier 1 ISPs

In Germany the Tier 1 ISP is

1. Deutsche Telekom AG

The South African Internet Region Tier 1 ISPs

In South Africa the Tier 1 ISPs are

1. Telekom South Africa
2. MTN
3. Vodacom
4. Neotel

The Ghana Internet Region Tier 1 ISPs

In Ghana the Tier 1 ISP is

1. Ghana Telecom

The Spain Internet Region Tier 1 ISPs

In Spain the Tier 1 ISP is

1. Telefonica

Across South America Telefonica has emerged as a dominant player although the Tier 1 status has not been confirmed.

The France Internet Region Tier 1 ISPs

In France the Tier 1 ISP is

1. France Telecom

* - Not verified

** - Not sure what happened to Reach and its Tier 1 peering in HK