Broadband Internet access: Encyclopedia II - Broadband Internet access - Overview

Broadband Internet access - Overview

Broadband is often called high-speed Internet, because it usually has a high rate of data. In general, any connection to the customer of 256 kbit/s (0.256 Mbit/s) or more 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 kbit/s (0.2 Mbit/s) in one direction, and advanced broadband is at least 200 kbit/s in both directions. The OECD has defined broadband as 256 kbit/s in at least one direction and this bit rate is the most common baseline that is marketed as "broadband" around the world. There is no specific bitrate defined by the industry, however, and "broadband" can mean lower-bitrate transmission methods. Some Internet Service Providers (ISPs) use this to advantage, in marketing lower-bitrate 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 takeup for these introductory products increases, telcos are starting to offer higher bit rate services. For existing connections, this most of the time simply involves reconfiguring the existing equipment at each end of the connection.

As the bandwidth delivered to end-users increases, the market expects that video on demand services streamed over the Internet will become more popular, though at the present time such services generally require specialised networks. The data rates on most broadband services still do not suffice 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 delivers high-quality video at 2 Mbit/s, at the high end of cable modem and ADSL performance. 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.

Adapted from the Wikipedia article "Overview", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki