How Does Broadband Work? Everything You Need to Know

Optic Cabel Closed Up (Credit : dvice.com)

While many urbanites take it for granted, broadband internet communication is one of those things that has only slowly penetrated the hinterlands of the United States. For people in rural Montana, internet connectivity can resemble using dialup modems, and more and more residents are becoming curious about whether broadband will reach their communities, and are asking, "how does broadband work?"

From a consumer perspective, broadband requires a modem and a high speed cable run out to their home; the two primary benefits of connectivity are download speed, and the fact that it doesn't monopolize a telephone line to be used. It's this lack of a high speed cable that's slowing down penetration into rural areas.

As to how it works in a technical sense, first we need to define a term: Bits per second. Original modems sent 300 bits per second; this rapidly went to 1200 bits per second, then 2400 bits per second, then really took off in the early 1990s. One byte (one character of text) is 8 bits, and file sizes are rated in kilobytes and megabytes (and gigabytes).

For transmission speeds, a critical part of how broadband works, old-style modems going over plain old telephone wires have a bandwidth cap of 56K per second. In the US, it effectively starts are 768K per second with asynchronous DSL (or ADSL), and can go upwards of 7-8 Bbits per second with high end digital cable lines for residential areas. Most home networking gear, whether wired or wireless, allows transmission on the local network at much higher rates than your connection to the Internet, though the amount of bandwidth available means most people won't notice. (It is why digital content providers are pushing home media servers, so that the server can download things you'll want to see and cache a local copy for everyone in the house to use.

How broadband works for most service providers is that it's asynchronous - the download speed is lower than the upload speed. Thus, when using a DSL line, the download speed is 768K/second and the upload peed will be about 256K/sec. Cable modem systems are usually bandwidth capped for upload speeds at about 1MB/sec, in large part as an effort to slow down the propagation of peer to peer file sharing networks.

The drawback of cable modem usage is that as the number of users on a subnet grows, the overall performance for all users drops proportionally. Each line is dedicated - there are no other people using your bandwidth and slowing it down. The drawback of DSL service is that you have to be within a certain distance (2 km) of the central switching station to get service at all. (One of the big infrastructure booms of the 1990s was rolling out more DSL lines by adding more switching capacity)

New elements of roll outs include "Fiber Optic To Home", or "FiOS". These use fiber optic cables all the way to the house, and can give bandwidth caps in excess of 10 Mbits per second. It's expensive, and is mostly used in higher rental or home priced areas.

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