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Dial-up access is a form of Internet access
through which the client uses a modem connected to a computer and a
telephone line to dial into an Internet service provider's (ISP) node to
establish a modem-to-modem link, which is then routed to the Internet.
Despite being the way people have connected to the internet for many
years, it is being steadily replaced by Broadband internet connections,
and nowadays DSL subscription plans cost the equivalent of slower
dial-up access. Until recently it was the cheapest method of internet
access, but is slowly losing that distinction.
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, many of which provide speeds greater than 1
Mbit/s, as well as reducing prices under dial-up prices offered by
companies such as Verizon. 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. These first person shooter style games are the most sensitive to
lag, making playing them on dial-up impractical.
High-speed dial-up What is often advertised as
"high-speed dial-up Internet" or "accelerated dial-up" by service
providers such as Earthlink and NetZero in the United States is a form
of dial-up access that utilizes the newer modem standard v.92 to shorten
the log-on (or handshake) process, and then once a connection has been
established the provider will selectively compress, filter, and cache
data being sent to the users home with the overall effect of increasing
the speed of browsing most standard web pages (see also proxy server).
The term high speed is misleading as these processes do not increase the
overall throughput of the line, only making more efficient use of the
bandwidth that is already there. Certain applications cannot be
accelerated, such as SHTTP, streaming media, or file transfers. The
compression of certain files such as pictures can have a negative effect
on the browsing experience of the user, due to the lower quality that it
imposes. |
