How Broadband Cable works... or doesn't
Most homes and businesses in the country have a choice of receiving their broadband either through the POTS (Plain Old Telephone Service) lines or through the coaxial cables which are used for delivery of television signals. Although there are effectively very little differences in the user experience between both types of broadband, the technical differences are significant. Although DSL uses a specific modem to feed the signal to and from your PC, cable uses a cable modem which works on completely different technology, although the result is the same.
The essence of the difference is that where DSL is an additional signal which travels along your POTS landlines, cable broadband is carried literally inside your television signal. The cable internet is transmitted inside a tunnel that is usually 6MHz wide and allows for download speeds of approximately 5 Mbps and upload speeds of around 256 Kbps. Cable internet broadband is even more sensitive to multiple users sharing the same bandwidth as ADSL, so this download speed is generally rarely achieved at times other than 6 am on a Sunday. When you have a lot of people trying to use the internet through the same cable broadband connection, each user is going to find that everything slooooooooooows down.
Your cable company has created a huge network in your area to service the broadband customers. Each neighborhood in your area is likely covered by a different network node. The average bandwidth that most cable operators provide to each node is approximately 27 Mbps. It doesn't take a math whiz to figure out that if you have 10 people on that node, each will be receiving about 2.7 Mbps of bandwidth. But if you have 400, each of you will have barely more bandwidth than you would get on a dialup modem.
Just because 400 people are currently utilizing the node that doesn't mean that the speed will drop to such Triassic levels. All 400 would have to be simultaneously downloading to use up the bandwidth to that extent. However, with the explosion in torrent downloads, that is no longer as absurd a prospect as it once was and many conventional coaxial cable broadband systems are swamped with users and they all complain about the sloooooooooooowness.
Many of the major cable television and broadband suppliers are in the process of upgrading their networks where possible to fiber optic which increases the bandwidth and up/download speeds considerably. It is important when considering a fiber optic installation to ensure that you have fiber straight through. If there is a fiber optic network connecting your cable headquarters to your street corner but it's normal coaxial cable from the corner to your house, you will not see any of the massive advantages that fiber optic networks offer.
You don't have to venture far to hear vociferous debate about which is better, faster, or more reliable, cable or ADSL broadband. The bottom line is that it differs from ISP to ISP and from location to location. I've experienced cable and ADSL broadband that was so fast I thought I had died and gone to heaven and also cable and ADSL broadband that was so sluggish it made me tear what little hair I have left out of my scalp. Similarly I've had ADSL and cable broadband that didn't work for hours or days on end. Fortunately with the advent of fiber optics, both ADSL and cable may soon be offering much faster, and hopefully far more reliable, service to broadband customers.