Dial-up Internet access
Dial-up access is an inexpensive but relatively slow form of Internet access in which the client uses a modem connected to the computer and a telephone line to dial the Internet service provider's (ISP) node, a dial-up 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. Despite the advent of widely available broadband Internet access in most parts of the Western world, many people worldwide still connect via dial-up simply because they do not have access to or cannot afford a high-speed Internet connection.
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 in countries such as the United States and Canada 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
Modern 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 and FCC regulation. These speeds are currently considered the maximum possible; in many cases transfer speeds will be lower, averaging anywhere between 33-43 kbit/s. Factors such as phone line noise and conditions, as well as the quality of the modem itself, play a large part in determining connection speeds.
Dial-up connections usually have high latency that can be as high as 200 ms or even more, which can make online gaming or videoconferencing difficult, if not impossible. Some games, such as Star Wars: Galaxies and The Sims Online are capable of running on 56 K dial-up. Gamers with dial-up connections are often disconnected from game servers due to the "lag", or high latency, of the connection.
Replacement by broadband
Broadband Internet access (via cable and DSL) has been increasingly replacing dial-up access in many parts of the world over the last five years. The reason for this is mostly due to broadband connections featuring speeds which far exceed the capacity of dial-up, ranging anywhere between 1-5 Mbit/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. Some of those that can be played with dial-up access, such as Unreal Tournament 2004, latency can be such that it can make the game unplayable.
High-speed dial-up
What is being advertised as "high-speed dial-up" by Earthlink and NetZero in the US is a form of dial-up Internet access that shortens the log-on (or handshake) process and, once online, selectively compresses, filters, and caches data, with the overall effect of increased the speed of browsing most web pages and email. These processes do not, however, increase the speed of directly downloading files (for instance, FTP or P2P usage) or of browsing secure (encrypted) web material. Essentially, the "high-speed dial-up" is normal dialup with a web accelerator built in.