Internet service provider
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An Internet service provider (ISP) is a company that provides access to the Internet, hosts data, or does both. Access ISPs connect customers to the Internet using copper, wireless or fiber connections.[1] Hosting ISPs lease server space for smaller businesses and host other people servers (colocation). Transit ISPs provide large tubes for connecting hosting ISPs to access ISPs. [2]
ISPs may provide Internet e-mail accounts to users which allow them to communicate with one another by sending and receiving electronic messages through their ISP's servers. ISPs may provide services such as remotely storing data files on behalf of their customers, as well as other services unique to each particular ISP.
History of ISPs
The internet started off as a closed network between government research laboratories and relevant parts of universities. It became popular and then universities and colleges started giving more of their members access to it. As a result, commercial Internet Service Providers occurred to provide access for mainly those who missed their university accounts. In 1990, Brookline, Massachusetts-based The World became the 1st commercial ISP (see http://www.zakon.org/robert/internet/timeline/, also published as RFC 2235 http://tools.ietf.org/html/rfc2235).
Access ISPs
ISPs employ a range of technologies to enable consumers to connect to their network.
For users and small businesses, the most popular options include dial-up, DSL (typically Asymmetric Digital Subscriber Line, ADSL), broadband wireless, cable modem, fiber to the premises (FTTH), and Integrated Services Digital Network (ISDN) (typically basic rate interface). For customers with more demanding requirements, such as medium-to-large businesses, or other ISPs, DSL (often SHDSL or ADSL), Ethernet, Metro Ethernet, Gigabit Ethernet, Frame Relay, ISDN (BRI or PRI), ATM, satellite Internet access and synchronous optical networking (SONET) are more likely to be used.
- Typical home user connection
- Typical business-type connection
Locality
When using a dial-up or ISDN connection method, the ISP cannot determine the caller's physical location to more detail than using the number transmitted using an appropriate form of Caller ID; it is entirely possible to e.g. connect to an ISP located in Mexico from the USA. Other means of connection such as cable or DSL require a fixed registered connection node, usually associated at the ISP with a physical address.
Hosting ISPs
Access ISPs get you online, but when you are there, where are the hard disks that are storing the images, text, audio, and video that you are browsing? The hard disks live in hosting ISPs.
Transit ISPs
Just as their customers pay them for Internet access, ISPs themselves pay upstream ISPs for Internet access. An upstream ISP usually has a larger network than the contracting ISP and/or is able to provide the contracting ISP with access to parts of the Internet the contracting ISP by itself has no access to.
In the simplest case, a single connection is established to an upstream ISP and is used to transmit data to or from areas of the Internet beyond the home network; this mode of interconnection is often cascaded multiple times until reaching a Tier 1 carrier. In reality, the situation is often more complex. ISPs with more than one point of presence (PoP) may have separate connections to an upstream ISP at multiple PoPs, or they may be customers of multiple upstream ISPs and may have connections to each one of them at one or more point of presence.
Peering
ISPs may engage in peering, where multiple ISPs interconnect at peering points or Internet exchange points (IXs), allowing routing of data between each network, without charging one another for the data transmitted—data that would otherwise have passed through a third upstream ISP, incurring charges from the upstream ISP.
ISPs requiring no upstream and having only customers (end customers and/or peer ISPs) are called Tier 1 ISPs.
Network hardware, software and specifications, as well as the expertise of network management personnel are important in ensuring that data follows the most efficient route, and upstream connections work reliably. A tradeoff between cost and efficiency is possible.
Derivatives
The following are not a different type of the above ISPs, rather they are derivatives of the 3 core ISP types. A VISP is reselling either access or hosting services. Free ISPs are similar, but they just have a different revenue model.
Virtual ISP
A Virtual ISP (VISP) is an operation which purchases services from another ISP (sometimes called a "wholesale ISP" in this context)[3] which allow the VISP's customers to access the Internet using services and infrastructure owned and operated by the wholesale ISP.
Free ISP
Free ISPs are Internet Service Providers (ISPs) which provide service free of charge. Many free ISPs display advertisements while the user is connected; like commercial television, in a sense they are selling the users' attention to the advertiser. Other free ISPs, often called freenets, are run on a nonprofit basis, usually with volunteer staff.
Related services
See also
- Federation of Internet Solution Providers of the Americas (FISPA)
- Free-net
- IP address
- Internet backbone
- Internet Provider Security
- Network access point
- Second-level ISP
- Wireless internet service provider