Network access point
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Network Access Point ("NAP") is the original term for the data communications facilities built in the early days of the Internet to provide on-ramp access to higher-speed Internet links (which were typically transcontinental or intercontinental in extent). Now known as Internet Exchange Points ("IXPs"), these facilities in their modern role are still an essential component of the global Internet infrastructure.
They were originally called Network Access Points because the early Internet was centred on a clearly defined higher-speed Internet backbone. An individual network joined the Internet by connecting to the backbone. This backbone was at first the ARPANET. It was later augmented and then replaced by NSFNET, which itself faded away. The modern Internet is independent of any single backbone.
Network Access Points originally allowed University networks to join the Internet by connecting to the NSFNET backbone. NAPs were provided at the regional level. A single NAP might serve a geographic area as extensive as a state. More than one region might connect to the backbone network at the same NAP. It was desirable for reasons of network efficiency that traffic heading for the NAP from different University networks be aggregated. In the US, a tier of Internet Service Providers was encouraged to develop between the backbone and the Universities. These Service Provider networks each had a high capacity link to, or a Point of presence at, one or more NAPs. It was the emergence of this intermediate tier of networks, and their eventual interconnection at a peer level, that gradually reduced the Internet's dependence on a backbone. Some peering was initially implemented at NAPs. This change caused the role of NAPs to evolve into that of the modern IXPs.