An Internet Service Provider (also known as an ISP or even as an IAP, internet access provider) is a firm that offers subscribers access to the internet. This internet service provider maintains large runs of cabling and maintains network services in order to transfer and deliver web content to those paying the subscription fee. Typically, these internet service providers focus on DSL, Cable modem, wireless, and more recently, dedicated high-speed interconnects such as T1 or fiber optic service (typically abbreviated Fios). While far less common, ISPs still offer dial up internet service, which is gradually become a phased out. All in all, there are many different types of Internet Service Providers, and within each and every internet service provider there are often varying levels of service, coverage, as well as personal customer service that comes attached with it. An Internet Service Provider is a complete package of services, which should be researched and considered before an Internet Service Provider is selected.
For most users, the most important qualification (beyond the ever present price point) is the speed of the connection. Depending on the intended use, there are a myriad of different internet services, and even varying levels of coverage within each and every service. The slowest of these is dial-up internet service. Modern dial-up transfers web content at a maximum rate of 56.6 kilobits per second. In the early days of internet service, this was typically sufficient, as websites were designed with a lean mentality, with very little imagery and a heavy emphasis on text, and text based linking. As time has progressed however, most websites assume that the user is on a high speed connection, and have therefore loaded their website with visual flair and high file size images. What was once acceptable no longer is for most web users, who opt to selecting a faster service.
Mid-Range services available for home include Cable Internet or Digital Subscriber Line (DSL) service. While DSL is available as slow as 128 Kilobits per second (just slightly more than twice the speed of dial-up service) most of these providers have since upgraded their capacity and provide service as fast as 3000 Kilobits per second. For most people, this is sufficient however there are currently faster services available to those who either desire them, or require them to operate their business.
For those simply not interested in paying for internet access, there are a very small number of Free ISPs available. These providers provide internet service free of charge, typically funded through advertising revenue (much like television broadcasts on most stations). Unfortunately, this variety of ISP is gradually falling by the wayside. Netzero, one the earliest example of this service no longer provides an ad supported internet service, and instead focuses on low priced services such as dial up.
All in all, an Internet Service Provider has the very complicated job of setting up and maintaining a network to connect its users to the internet. The inner workings of an ISP vary significantly from company to company, and much of their inner workings are company secret. It's difficult to understand just how internet service providers operate, however from the buyer's perspective the process of using an ISP are incredibly simple. Once a level of connectivity is decided upon, it's simply up to the buyer to research their alternatives, and determine the best solution for their budget and needs.