Broadband Internet Aurora IL

Broadband Internet access, often referred to as "broadband Internet" or simply "broadband", is an internet connection with a high data-transmission rate. DSL and cable modem, both popular consumer broadband technologies, are typically capable of transmitting 256 kilobits per second or more, at approximately nine times the speed of a modem using a standard digital telephone line.

Broadband Internet access became a rapidly developing market in many areas in the early 2000s; one study found that broadband Internet usage in the United States grew from 6% in June 2000 to over 30% in 2003. Modern consumer broadband implementations, up to 20 Mbit/s, are several hundred times faster than those available at the time of the popularization of the Internet (such as ISDN and 56 Kbit/s) while costing less than ISDN; though performance and costs vary widely between countries.

Overview

Broadband is often also referred to as high-speed Internet, due to its usually high rate of data transfer. In general, any connection to the customer of 256 Kbit/s (0.256 Mbit/s) or higher is considered broadband Internet. The International Telecommunication Union Standardization Sector (ITU-T) recommendation I.113 has defined broadband as a transmission capacity that is faster than primary rate ISDN, at 1.5 to 2 Mbit/s. The FCC definition of broadband is 200 Kbits/s (0.2 Mbit/s) in one direction, with advanced broadband being at least 200 kbit/s in both directions. The OECD has defined broadband as 256 Kbit/s in at least one direction. Though there is no specific bit rate defined by the industry, the one defined by the OECD is the one used most often as the common baseline around the world. Broadband can mean lower-bit rate transmission methods though, which some Internet Service Providers (ISPs) use to their advantage, marketing lower-bit rate connections as broadband.

In practice, the advertised bandwidth is not always reliably available to the customer; ISPs often allow a greater number of subscribers than their backbone connection can handle, under the assumption that most users will not be using their full connection capacity very frequently. This aggregation strategy works more often than not, so users can typically burst to their full bandwidth most of the time. However, peer-to-peer file sharing systems, often requiring extended durations of high bandwidth, stress these assumptions and can cause major problems for ISPs who have excessively overbooked their capacity. For more on this topic, see network traffic engineering. As take up for these introductory products increases, telcos are starting to offer higher bit rate services. For existing connections, this usually involves reconfiguring the existing equipment at each end of the connection.

As the bandwidth delivered to end-users increases, it is expected that video on demand services being streamed over the Internet, which currently require specialized networks, will become more popular. Currently, the data rate typical on most broadband services is not sufficient to provide good quality video, as MPEG-2 quality video requires about 6 Mbit/s for good results. Adequate video for some purposes becomes possible at lower data rates, with rates of 768 kbit/s and 384 kbit/s used for some video conferencing applications. The MPEG-4 format, at the higher end of cable modem and ADSL performance, delivers high-quality video at 2 Mbit/s. The Ogg Tarkin format is intended to deliver similar performance.

Increased bandwidth has already made an impact on newsgroups: postings to groups such as alt.binaries have grown from JPEG images to entire CD and DVD images. According to NTL, the level of traffic on their network increased from a daily inbound news feed of 150 gigabytes of data per day and 1 terabyte of data out each day in 2001 to 500 gigabytes of data inbound and over 4 terabytes out each day in 2002.

Digital Subscriber Line, or DSL, is a family of technologies that provides digital data transmission over wires used in the "last mile" of a local telephone network. Typically, the download speed of DSL ranges from 128 kilobits per second (Kbps) to 24,000 Kbps depending on DSL technology and service level implemented. Upload speed is lower than download speed for ADSL and symmetrical for SDSL.

Hardware

The subscriber end of the connection consists of a DSL modem. This converts data from the digital signals used by computers into a voltage signal of a suitable frequency range to be applied to the phone line.

In the early days of DSL, installation required a technician to visit the premises. A "splitter" was installed near the demarcation point, from which a dedicated data line was installed. Today, many DSL vendors offer a self-install option, in which they ship equipment and instructions to the customer. In this case, because no changes are made to the cable plant on the customer premises, all phone wires are carrying both POTS and DSL signal frequencies. Therefore, customers generally need to plug a DSL filter into each telephone outlet. However, this can sometimes cause degradation of the DSL signal (especially if more than 5 analogue devices are connected to the line) because the DSL signal is present on all telephone wiring in the building. A way to circumvent this problem is to install one filter upstream from all telephone jacks in the building, except for the jack to which the DSL modem will be connected. Because this requires wiring changes by the customer and may not work on some (poorly designed) household telephone wiring, it is rarely done. It is much easier to install filters at each telephone jack in use. In the past, establishing new cable modem or satellite broadband service generally did require a visit by a technician to the premises, but this too has changed. Cable companies now deploy self install kits which enable their customers to get set up without a truck roll.

At the exchange, a digital subscriber line access multiplexer (DSLAM) terminates the DSL circuits and aggregates them, where they are handed off onto other networking transports. It also separates out the voice component.

Protocols & Configurations

Many DSL technologies implement an ATM layer over the low-level bit stream layer to enable the adaptation of a number of different technologies over the same link.

DSL implementation may create bridged or routed networks. In a bridged configuration, the group of subscriber computers connect into a single subnet. The earliest implementations of the bridged configuration used DHCP to provide network details, such as the IP address, to the subscriber equipment, with authentication via MAC address or an assigned host name. Later implementations often use PPP over Ethernet or ATM (PPPoE or PPPoA), while authenticating with a user id and password and using PPP mechanisms to provide network details.

DSL also has contention ratios which need to be taken into consideration when deciding between broadband technologies.

The origin of Digital Subscriber Line technology dates back to 1988, when engineers at Bellcore (now Telcordia Technologies) devised a way to carry a digital signal over the unused frequency spectrum available on the twisted pair cables running between the telephone company's central office and the customer premises. Implementation of DSL could permit an ordinary telephone line to provide digital communication without interfering with voice services. However, incumbent local exchange carriers (ILEC) were not enthusiastic about DSL. It was less profitable than installing a second phone line for consumers who preferred simultaneous connections and had the capability to cannibalize existing ISDN customers. This changed in the late 1990s when cable television companies began marketing broadband Internet access. Realizing that most consumers would prefer broadband Internet to dial-up Internet, ILECs rushed out the DSL technology, which they had delayed implementing, as an attempt to win market share, which was being consumed by these cable television operators.

DSL is the principal competition of cable modems for providing high speed Internet access to home consumers in Europe and North America. Older ADSL standards can deliver 8 Mbit/s over about 2 km (1.24 miles) of unshielded twisted pair copper wire. The latest standard, ADSL2+, can deliver up to 24 Mbit/s, depending on the distance from the DSLAM. Some customers, however, are located farther than 2 km (1.24 miles) from the central office, which significantly reduces the amount of bandwidth available (thereby reducing the data rate) on the wires.

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