Dial-up access
From Freepedia
Dial-up access is an inexpensive but extremely 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, though hundreds of thousands of people worldwide still use it simply because they can't get anything faster for one reason or another.
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 travellers. Dial-up is usually the only choice available for most rural or remote areas where getting a broadband connection is impossible due to low population and demand. Sometimes, dial-up access may also be an alternative to people who have limited budgets, though broadband is now increasingly available at lower prices due to market 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.
Performance
Dial-up modems typically have a maximum theoretical speed of 56 kbit/s (using the V.92 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 200ms 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. An increasing amount of Internet content such as Macromedia Flash, online gaming and streaming media require large amounts of bandwidth. Many computer games released in 2005 (such as Battlefield 2 or Star Wars Battlefront) are not compatible for online play with dial-up modems. It is likely that this trend will continue into the future.
