Friday, November 30, 2012
Broadband Internet - An Overview
The term "broadband" refers to a wide variety of Internet connectivity technologies which utilize a wide frequency band to allow computer networking at speeds well beyond those of dial-up.
Broadband Internet connections frequently "piggyback" on existing infrastructure like television coaxial cable, power lines, or even telephone cables for the last mile; the backbone of the system is more often than not fiber-optic, but most systems are copper from at a minimum the node to the user's home. In almost all cases, these long-distance standards will terminate with the broadband modem, which connects to the ISP's network and can be connected to be a user's equipment using commodity Ethernet cables. In some parts of the world, Ethernet to the home is viable; this is capable of great speeds, but as Ethernet cables are ill-designed for long-range use it's not possible outside of exceptionally dense urban centers.
In recent years, mobile broadband has become popular as well. Mobile broadband standards like the 3GPP Long Term Evolution standard marketed as 4G LTE in the United States use cellular telecommunications towers to transmit data to and from an end-user's equipment. These mobile broadband standards provide high speeds, but are substantially more expensive than most comparable home broadband systems; as such, they're largely limited to use in portable devices like smartphones, tablets, and small laptop computers.
In home broadband, the most common technologies to see are DSL, cable, fiber-optic, and satellite internet connections. Each of these has its own advantages and disadvantages.
Digital subscriber line, typically referred to by the initialism DSL, uses the wired phone network to transmit data; however, unlike dial-up, DSL uses a wider band distinct from that used for voice communication, as opposed to modulating the digital signal from the connected machine to the very narrow band the telephony network uses for voice communications. As a result, DSL can manage significantly greater speeds (typically around 8Mbps) from the same network of physical cables.
Cable broadband, high speed internet connections are a step up from DSL, with significantly higher speeds due to using the higher-bandwidth cable television infrastructure to deliver the signal. While a cable connection is pricier than a DSL connection, they're still very attainable for most people, and the existing infrastructure which is used is still fairly prevalent; as a result, cable Internet connections are very common due to hitting a good balance between speed, availability, and pricing.
Fiber-optics hold a place in most broadband networks; however, what's sold as "fiber-optic broadband Internet" is fiber-to-the-home. By utilizing optical fiber, narrow glass tubes the size of human hairs, it's possible to transmit a digital signal via on-off pulses of light. Since light moves substantially faster than electricity, this results in a faster connection- more bandwidth and lower latency. However, fiber-optics are expensive to make, lay, and maintain; this makes fiber-to-the-home somewhat uncommon except in wealthy urban areas.
Lastly, there's satellite Internet access. By using a dish to connect to a satellite in low Earth orbit, it's possible to get broadband speeds anywhere on the globe, even in places without other broadband technologies available. However, high costs and high latency (the latter due to the enormous distance crossed from dish to satellite and consequent speed-of-light delays) have limited adoption of this technology.