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Definition: ISP
(1) See in-system programmable.
(2) (Image Signal Processor) See image processor.
(3) (Internet Service Provider) An organization that provides access to the Internet. Email accounts may also be part of the service. Also called an "Internet host," an ISP connects to users via cable, DSL, FiOS or satellite; however, ISPs can also deliver service via analog dial-up, ISDN, private lines and wireless (see WISP). Customers are generally billed a fixed rate per month but there may be extra charges (see data cap). See The World, DSL, cable Internet, FiOS and SISP.
Your Own Website
ISPs may host a website for their customers, allowing them to have a presence on the Web. However, the website may be limited to a maximum number of pages, and the domain name of the ISP becomes part of the customer's URL address. For a fee, an ISP may host a website that uses its customer's proprietary domain name (see Web hosting). See download vs. upload, IXP and backbone.
The Cellular Carrier Is Your ISP
For smartphone users, the ISP is the cellular carrier, such as Verizon and T-Mobile. Monthly plans are available for unlimited data or per gigabyte. See carrier data plans and Broadband Facts.
Top ISPs
In 2024, CNET ranked AT&T Fiber as the best fiber service and Spectrum as the best cable service. At the same time, U.S. News ranked Verizon FiOS as best overall, Xfinity Internet as the least expensive and Google Fiber as the fastest. CBS News ranked Verizon best overall and AT&T the best runner-up. In general, fiber-optic providers ranked best overall from numerous reviews.
How They're Connected
More than a Quarter Century Ago
(2) (Image Signal Processor) See image processor.
(3) (Internet Service Provider) An organization that provides access to the Internet. Email accounts may also be part of the service. Also called an "Internet host," an ISP connects to users via cable, DSL, FiOS or satellite; however, ISPs can also deliver service via analog dial-up, ISDN, private lines and wireless (see WISP). Customers are generally billed a fixed rate per month but there may be extra charges (see data cap). See The World, DSL, cable Internet, FiOS and SISP.
Your Own Website
ISPs may host a website for their customers, allowing them to have a presence on the Web. However, the website may be limited to a maximum number of pages, and the domain name of the ISP becomes part of the customer's URL address. For a fee, an ISP may host a website that uses its customer's proprietary domain name (see Web hosting). See download vs. upload, IXP and backbone.
The Cellular Carrier Is Your ISP
For smartphone users, the ISP is the cellular carrier, such as Verizon and T-Mobile. Monthly plans are available for unlimited data or per gigabyte. See carrier data plans and Broadband Facts.
Top ISPs
In 2024, CNET ranked AT&T Fiber as the best fiber service and Spectrum as the best cable service. At the same time, U.S. News ranked Verizon FiOS as best overall, Xfinity Internet as the least expensive and Google Fiber as the fastest. CBS News ranked Verizon best overall and AT&T the best runner-up. In general, fiber-optic providers ranked best overall from numerous reviews.
Small ISPs hook into regional ISPs or directly into major backbone providers. This diagram shows a local ISP confined to a single county, and a regional ISP confined to a state. In practice, ISP networks often have irregular boundaries that span jurisdictions.
In the early days of the Internet, ISPs were coming out of the woodwork, witness this Boardwatch Magazine directory that itemized 3,600 in 1997. For residential customers, the service was dial-up and analog modems. After years of consolidation, only about a third that number of service providers exist today. (Image courtesy of Boardwatch Magazine.)