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Tier 1

(1) See Tier 1 network.

(2) The top level. A Tier 1 city is one of the major metropolitan areas in a country. A Tier 1 vendor is one of the largest and most well-known in its field. However, the term can sometimes refer to the bottom level or first floor. For example, the U.S. government labeled Tier 1 Y2K compliance as the bottom level.



Tier 1 network

A top-level network on the Internet. There are about a dozen Tier 1 networks, most of which are in the U.S., including AT&T, Global Crossing, Level 3, Qwest, Sprint and Verizon (originally UUNET). Known as "settlement-free peering," Tier 1 networks are private networks that allow traffic from other Tier 1 networks to transit their backbones without a fee. See peering and IXP.

Tier 2 and Tier 3 Networks
Tier 2 networks peer with some networks without fees but pay to reach a large portion of the Internet. Tier 3 networks always pay fees to obtain access to the larger backbones.

ARPAnet to NSFnet to Tier 1
ARPAnet was the original Internet backbone, which was superseded by the National Science Foundation Network (NSFnet) in the late 1980s. NSFnet was replaced by Tier 1 networks in the mid-1990s when the Internet became a commercial venture. See ARPAnet, NSFnet and Internet.



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Before/After Your Search Term
BeforeAfter
TIB/RendezvousTier 1 application
TIBCO RendezvousTier 1 database
TICTier 1 ISP
tickTier 1 network
ticketTier 2 network
tickleTier 3 network
tickle packettiered storage
ticklerTIES
tickletTIF
Tier 0 storageTIF file

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