An IAP (Internet access provider) is a company that provides individuals and other ISP companies access to the Internet. An IAP is a type of Internet service provider (ISP). (The other main service that an ISP provides is Web site building and virtual hosting.) An IAP has the equipment and the telecommunication line access required to have POP on the Internet for the geographic area served. The larger IAPs have their own high-speed leased lines so that they are less dependent on the telecommunication providers and can provide better service to their customers. Among the largest national and regional ISPs are AT&T WorldNet, IBM Global Network, MCI, Netcom, UUNet, and PSINet.
IAPs also include regional providers such as New England's NEARNet and the San Francisco Bay area BARNet. They also include thousands of local providers. In addition, Internet users can also get access through online service providers (OSP) such as America Online.
The larger IAPs interconnect with each other through MAE (ISP switching centers run by MCI WorldCom) or similar centers. The arrangements they make to exchange traffic are known as peering agreements. There are several very comprehensive lists of IAPs (usually identified as ISPs) available to Web users.