Editing Tier 1 network (section)

==History==
The original [[Internet backbone]] was the [[ARPANET]] when it provided the routing between most participating networks. The development of the British [[JANET]] (1984) and U.S. [[National Science Foundation Network|NSFNET]] (1985) infrastructure programs to serve their nations' higher education communities, regardless of discipline,<ref name="internetsociety.org">{{cite web|url=https://www.internetsociety.org/internet/history-internet/brief-history-internet/|title=Brief History of the Internet|website=Internet Society|language=en-US|access-date=2019-01-22}}</ref> resulted in the [[National Science Foundation Network|NSFNet]] backbone by 1989. The Internet could be defined as the collection of all networks connected and able to interchange [[Internet Protocol]] datagrams with this backbone. Such was the weight of the NSFNET program and its funding ($200 million from 1986 to 1995)—and the quality of the protocols themselves—that by 1990, when the ARPANET itself was finally decommissioned, TCP/IP had supplanted or marginalized most other wide-area computer network protocols worldwide.

When the Internet was opened to the commercial markets, multiple for-profit Internet backbone and access providers emerged. The network routing architecture then became decentralized and this meant a need for exterior routing protocols: in particular, the [[Border Gateway Protocol]] emerged. New Tier 1 ISPs and their peering agreements supplanted the government-sponsored NSFNet, that program being officially terminated on April 30, 1995.<ref name="internetsociety.org"/> The NSFnet-supplied regional networks then sought to buy national-scale Internet connectivity from these now-numerous private long-haul networks.