Dial Up Access

Dial-up Internet access is an inexpensive but relatively slow form of internet access in which the client uses a modem to dial the internet service provider's (ISP) node, a dialup server type such as the Point-to-Point Protocol and TCP/IP protocols to establish a modem-to-modem link, which is then routed to the Internet. It is now regarded as legacy technology given the advent of widely available broadband Internet access in the Western world.

Dial-up Access: Availability

Dial-up requires no additional infrastructure on top of the telephone network. As telephone points are available throughout the world, dial-up remains useful to travelers. Dial-up is attractive in rural or remote areas where getting a broadband connection is impossible or expensive. Sometimes, dial-up access may also be an alternative to people who have limited budgets, though broadband is now increasingly available at lower prices because of competition.

Dial-up requires time to establish a telephone connection and perform handshaking before data transfers can take place, potentially a source of frustration. In locales with telephone connection charges, each connection incurs an incremental cost. If calls are time-charged, the duration of the connection incurs costs.

Dial-up access is a transient connection, because either the user or the ISP terminates the connection. Internet service providers will often set a limit on connection durations to prevent hogging of access, and will disconnect the user -- requiring reconnection and the costs and delays associated with that.

Dial-up Access: Performance

Dial-up modems typically have a maximum theoretical speed of 56 kbit/s (using the V92 protocol), although in most cases only up to 53 kbit/s is possible due to overhead. Also, these speeds are the maximum possible; in almost all cases transfer speeds will be lower, averaging about 10 kbit/s. Line noise further reduces achieved transfer rates.

Dial-up connections usually have high latency that can be as high as 400ms or even more, which can make online gaming or videoconferencing difficult, if not impossible.

Broadband Internet access (mostly via. cable and ADSL) have been replacing dial-up connections in the last five years. The reason for this replacement is mostly because broadband connections usually have speeds which far exceed the capacity of dial-up, in some cases up to 15,360 kbit/s.

This article is adapted from: wikiPedia.com.