Animal (networks)

Tiers (English for rank) are categories or classes in which Internet service providers are classified depending on their size. There is no authority that defines different tiers. Rather, they are vague definitions that leave a lot of space. Since not all business relationships can be traced due to confidentiality agreements , a differentiation can prove difficult.

Tier 1

Large autonomous systems (AS) that no longer buy transit , but only operate peering connections with other autonomous systems and can thus reach the entire Internet free of charge, form the upper class ( tier 1 ). According to the strict interpretation of the above definition, the following providers worldwide belong to this category:

• Germany: Deutsche Telekom
• France: orange
• Hong Kong: PCCW
• Italy: Telecom Italia
• India: Tata Communications
• Japan: NTT
• Spain: Telxius (subsidiary of Telefónica )
• Sweden: Telia
• USA: AT&T , GTT , CenturyLink (formerly Level 3 Communications , Qwest, Savvis and Global Crossing), Verizon UUNET (formerly XO), T-Mobile US , Zayo (formerly AboveNet)
• United Kingdom: Liberty Global , Colt Technology Services

Tier 2

For Tier 2 -Providern, also called transit providers include most autonomous systems on the Internet. They are characterized by the fact that their operators buy connectivity from Tier 1 ASs on the one hand ( downstream ) and on the other hand sell connectivity to Tier 3 ASs ( upstream ). At the same time, peering with other tier 2 networks is operated.

Both when deciding on how to link ASs and when routing the packets themselves, economic issues are paramount. It is therefore also possible for large tier 1 providers to peer with smaller tier 2 providers if they hope that this will give them an advantage, such as the possibility of reaching a large number of end customer connections.

Examples

• Vodafone
• Comcast
• Tele2
• Swisscom (Switzerland)

Tier 3

The last category, Tier 3 , is made up of smaller, local providers who generally do not sell transit traffic to other autonomous systems themselves. Tier 3 providers sometimes peer with one another and sell transit primarily to end users. You have a locally restricted fiber optic network.

Examples

• Tele Columbus

Individual evidence

1. ↑ Holger Bleich: Bosses of the fibers - The infrastructure of the Internet. Retrieved November 1, 2014 . 
2. ^ Stefan Dierichs, Norbert Pohlmann: Internet Germany - structure and structure. Retrieved November 1, 2014 . 
3. ↑ Stefan Dierichs, Norbert Pohlmann: This is how Internet routing works. Retrieved November 1, 2014 . 

literature

• James F. Kurose , Keith W. Ross: Computer Networks: The Top-Down Approach ISBN 978-3-8273-7330-4 (standard work)

Web links

• Das Internet , Institute for Internet Security, Westfälische Hochschule, accessed on November 1, 2014