ISPs 101: Internet service providers

Internet service providers, or ISPs, bring their large internet networks to consumers through home or business internet service. If you're thinking about changing your internet service, you may have questions about ISPs. Keep reading for an overview of what internet service providers do, how they connect you to the internet, and how you can choose the right one for you.

What is an ISP?

Internet service providers do exactly what the the name says: provide internet service to customers. They can work in both home (residential) and business (commercial) environments. ISPs first emerged in the late 1980s and the early 1990s, when internet access started to become widespread.


Initially, telephone companies operated as ISPs because of the prevalence of dial-up internet, which used the exact same lines as landline phone service. Later, these companies expanded into broadband providers of DSL internet. Then, in the late 1990s and early 2000s, cable broadband was introduced, and many cable companies began offering internet service alongside TV and voice services.


Today, there are hundreds of different internet service providers, and they can be commercial companies, non-profits, or publicly-owned utilities. Depending on where you live, you may have a number of different ISPs to choose from to get your internet service.

How do ISPs connect you to the internet?

The internet is essentially made of millions of computers that “talk” to each other over global networks. When you send or access any piece of data over the internet (like a shopping website, a photo on social media, or an email), it's transmitted over larger network that your ISP connects directly to your home. 


You can think of ISPs as similar to railroad companies. Your data is a train, but it can't go anywhere unless it has railroad tracks to run on. You pay the ISP a fee to use their “tracks,” which in turn link to a larger series of tracks. This allows your train to travel back and forth, eventually getting to wherever you want it to go. You pay to use the tracks just as you pay to ride a real train, because so much money goes into building and maintaining the whole infrastructure.

Types of ISPs

There are several types of internet service providers that have slightly different ways of operating:


  • Access ISPs are the most common type of ISP. They use dial-up or broadband internet connections, such as DSL, fiber optics, cable, or satellite to deliver internet to residential and business internet consumers.   

  • Mailbox ISPs specialize in providing email services for customers using special types of servers to store, send, and receive mail. Most Access ISPs also offer this service.

  • Hosting ISPs host (or house) websites, files, “virtual machines” and cloud-based servers, and are typically used by businesses and companies, not individuals.

  • Transit ISPs specialize in connecting hosting ISPs to access ISPs, moving traffic from one ISPs infrastructure to another.

  • Virtual ISPs purchase or rent services from other ISPs to provide internet access, rather than building their own internet infrastructure.

  • Free ISPs are a type of access ISP that offer services free of charge, using advertisements to make money on the web traffic of their customers.

High-speed internet providers

Today, most ISPs are high-speed internet providers offering broadband internet through DSL, cable, satellite, or fiber-optic technologies. The connection speeds for these providers are much faster than older types of internet connections, like dial-up.

How to choose an internet service provider

Now that you know more about the types of internet providers, you may be wondering how to choose one. The truth is, the types of networks and services available vary quite a bit based on your location. It's a good idea to start by searching for local ISPs, using a web search like "internet service provider near me" or "internet provider in [name of your city or town]."


The next step is to determine how much speed you need for your household, and then compare rates and plans. Consider the type of agreement or contract, check reviews by other subscribers, and look for special promotions on installation and modems.


CenturyLink is a high-speed internet service provider with both residential and business internet service offerings. We are also expanding our fiber internet network throughout the country and offer a Simply Unlimited internet plan. Check availability now to make CenturyLink your next internet service provider!

See what internet speeds are available in your area

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