What is Network access points (NAP)?
A Network Access Point (NAP) was a public network exchange facility where Internet service providers (ISPs) connected with one another in peering arrangements. The NAPs were a key component in the transition from the 1990s NSFNET era (when many networks were government sponsored and commercial traffic was prohibited) to the commercial Internet providers of today. They were often points of considerable Internet congestion.
Imagine that Company A is a large ISP. In each major city in the UK, Company A has a POP. Company A leases fiber optic lines from a leased line telecoms provider (Openreach) to connect the POPs together.
Imagine that Company B is a corporate ISP. Company B builds large buildings in major cities across the UK and corporations locate their Internet server machines in these buildings. Company B is such a large company that it runs its own fiber optic lines between its buildings so that they are all interconnected.
In this arrangement, all of Company A’s customers can talk to each other, and all of Company B’s customers can talk to each other, but there is no way for Company A’s customers and Company B’s customers to intercommunicate. Therefore, Company A and Company B both agree to connect to NAPs in various cities, and traffic between the two companies flows between the networks at the NAPs.
In the real Internet, dozens of large Internet providers interconnect at NAPs in various cities, and trillions of bytes of data flow between the individual networks at these points. The Internet is a collection of huge corporate networks that agree to all intercommunicate with each other at the NAPs. In this way, every computer on the Internet connects to every other.