Internet service provider

An Internet service provider (ISP) is an organization that provides various services to help people access and manage the Internet. These organizations can be commercial businesses, non-profits, or community-owned entities. Beyond simple connectivity, ISPs offer services like domain name registration, web hosting, and colocation. They also manage mailbox services, which host email domains and provide storage for electronic mail.

By acting as a bridge, ISPs allow users to participate in the global digital network.

The process of connecting to the Internet involves a sequence of network layers. It begins with an access provider that connects directly to the end customer, such as a home or a business. This provider uses different technologies to send data, including copper wires for dial-up or Digital Subscriber Line (DSL) connections. For faster speeds, providers use cable modems or fiber optics. Fiber-to-the-home (FTTH) uses thin glass strands to transmit data through light.

Once the signal leaves the customer, it moves into an aggregation network. From there, it enters a core network, also known as a backbone, to travel long distances.

ISPs are classified into different types based on how they connect to the global network. Access providers are the most common type for everyday users, offering technologies like Wi-Fi, cellular, or satellite access. Mailbox providers focus on hosting email servers using protocols like Simple Mail Transfer Protocol (SMTP). Hosting ISPs provide specialized services like cloud computing or physical server operation. There are also virtual ISPs (VISPs), which are operations that purchase services from a wholesale ISP to serve their own customers.

The history of these providers shows how the Internet moved from research to public use. Originally, the network was known as ARPAnet and connected government labs and universities. In the 1980s, online services like CompuServe and America Online (AOL) offered limited features like email. The first true commercial ISPs emerged in 1989 in Australia and the United States. In the U.S., a company called The World became the first commercial ISP in Brookline, Massachusetts, serving its first customer in November 1989. By 1995, the decommissioning of NSFNET removed the last major restrictions on commercial traffic.

To move massive amounts of data, ISPs use a hierarchical tier system. Tier 3 ISPs usually focus on providing service to individual customers and businesses. They must purchase transit, or access to the rest of the Internet, from higher tiers. Tier 2 ISPs have larger networks and may engage in peering, which is a way to exchange traffic with other networks. Tier 1 ISPs sit at the top of the hierarchy and own massive networks.

These top-tier providers use advanced systems like Dense Wavelength-Division Multiplexing (DWDM) to send data through optical fiber over huge distances.

Data transmission relies on both metro and long-haul networks to function. Metro networks handle traffic within a specific city or metropolitan area. Long-haul networks transport data across much larger distances, often using submarine cables under the ocean. Some systems are capable of ultra long-haul transmission, which covers distances exceeding 1,500 kilometers. To manage these connections, ISPs often use data centers that host "meet-me rooms" where different networks can connect to one another.

In recent years, the role of ISPs has been shaped by legal discussions regarding net neutrality. This concept involves whether ISPs should treat all internet traffic equally. In 2015, the U.S. Federal Communications Commission (FCC) ruled in favor of net neutrality by reclassifying broadband as a telecommunications service under Title II. This was intended to prevent providers from creating "fast lanes" for certain content. However, the policy changed again in 2018 when the FCC's network neutrality rules were repealed. These debates highlight how much influence ISPs have over how information moves through the digital world.