Our Sites:
When discussing the efficiency or speed of computer network communication, the term bandwidth is often used. Unlike electronic communications, for example, radio, which refers to the “band” of frequencies available, computer network bandwidth is term usually related to measuring how much information can be transferred across the network at any one time.
Measuring the bits
There is not yet universal agreement on ways to represent the terms used to measure bits, bytes and the like, the units of measurement that apply to computer network bandwidth. This can make coming to terms with the jargon a real challenge at times.
Common representations of these measurements include: bits (b or bit), kilobits (kb or kbit), megabits (Mb or Mbit), gigabits (Gb or Gbit) or megabytes (MB), megabytes per second (MBps or mbps or Mbps) and megabits per second (Mbit/s or mbps or Mbps). There are approximately 1000 kilobits per one megabit and there are eight bits (b) per byte (B). (Which means a megabyte is much much bigger than a kilobit).
Note: the abbreviation mbps and Mbps can apply to either megabyte or megabit – making things even more confusing!
In addition, computer network bandwidth can also be simply expressed as “lo” or “hi”, the latter being the type needed to view most videos on the Internet. Of course, the Internet is actually a succession of “packets” of information being passed from one link to another, so while the user may have the fastest bandwidth available, the file will only be passed to you as fast as the server it is coming from and your connection speed allow.
Here’s an example. If a woman called Rita downloads a video with ADSL2+, which gives her a download speed of up to 7Mbit/s, she can still only download it as fast the server can send it to her. If the server it is coming from has a lower speed than her connection she will receive the file at the speed of the server, not her maximum possible speed. Another user, Steve, has a dial-up connection with a theoretical maximum of 56kbps. In this case, the server speed is likely to be faster than his so in this case it is his connection that slows the delivery.
(It works differently if you are using Bit torrent to stream, however, but there’s not enough space to cover that in this article. In brief, with Bit torrent the people receiving the data then pass it on to the next user – so you can be impacted by the connection speeds of the different users up and downstream from you.)
Variations in bandwidth
The width of a band varies among the types of Internet connections available. There are two main types – dial-up and broadband. The broadband possibilities include: cable, satellite, wireless, ADSL and ADSL2+. All broadband connections are much faster than dial-up (you can get speeds from 128kbps to 2000kbps, or more, versus dial-up’s 56kbps). The general speeds are:
Cable
Cable currently sits around 10Mbit/s, but Virgin in the UK has recently announced that it will expand bandwidth in its cable service to 20Mbit/s in order to compete with ADSL 2+. Plans to increase bandwidth to 50Mbit/s will more than likely be successful on cable before the copper lines of the telephone. In Australia, the fastest available cable connection is 17Mbit/s with Telstra, but most of their cable plans have speeds of 8Mbit/s.
ADSL and ADSL2+
Standard ADSL speeds start from 256kbps for standard lines, to the newest ADSL2+. In Australia, Telstra is offering a limited service of ADSL2+, depending on location, with speeds up to 20Mbit/s. While Internode offers up to 24Mbit/s, a recent survey it conducted with its customers revealed that only “…13.4 percent achieve a download synch speed of higher than 20Mbit/s”. Still, at least you have a chance of a higher speed when circumstances allow…
Wireless
Wireless LAN networks are very convenient for people who travel with their computer a lot, but the downfall is that you need to be near a “hotspot” to access the Net. Check with the provider first to see if they have hotspots in the areas where you are most likely to need to be. Basic wireless connections have speeds of up to 256kbps, while faster connections can be up to as much as 1.5 Mbit/s.
As with most contracts, there are usually limits on your download volume. Some providers may not change for extra downloads once limits have been reached, but instead reduce the bandwidth available (slow your connection) until the following month.
Dial-up Internet
It was the greatest thing when it first came out but these days dial-up is the grandmother of Internet connection options. As dial-up Internet relies on a standard telephone line to connect you to an Internet service provider (ISP) the connection is very slow – the technology has moved on from phone lines to much faster forms of wiring (or wireless!). Phone lines have a very narrow bandwidth (about 50kbps or 50,000 bits per second). However, most people have phone lines – the telcos long ago made the investment in that infrastructure – so it’s cheaper to connect. It can just take a lot longer to download your pages and data. Save the money and spend the time or spend the money and save the time… these are just some of the considerations for the end-user, another being not being able to use the phone and surf the Net at the same time.
Additional Information
If you’d like to know more the Web, of course, is the best source of information on all things Net. To get you started, take a peek at what some cool nerds have to say about bandwidth, or check out a couple of more mainstream sites such as this BigPond broadband satellite link or the Australian Broadband Guide.
