Cable

At a glance

Cable is considered to be more stable than ADSL, with consistently high speeds. The large carriers like Telstra and Optus provide bundled deals with your phone and/or cable TV, which can save you quite a bit of cash in the long run. However, the installation process is more complex than ADSL, and may require a tradesman to run a cable into your house from out in the street. Furthermore, cable is restricted to certain areas in Australia, so you will need to check your ISP's Web site to see if your region is covered.

The fibre networks that bring you cable TV at home can be more than an addition to your viewing options -- it can also be your means to fast Internet access.

HFC (hybrid fibre-coaxial) networks that are used to carry cable TV pictures are also capable of carrying data at very high rates. The current cable TV signal doesn't take up all of the available bandwidth, because these cable networks were designed to carry a digital TV signal, rather than the previous analogue signal -- and this spare bandwidth can also be used to carry Internet data.

In theory, if you can get cable TV, you can get cable Internet. Telstra Big Pond Advance Cable is available in Brisbane, Melbourne and Sydney. OptusNet Cable (formally Optus@Home) and BigPond Broadband Cable are available in most metropolitan areas.

However, people who live in blocks of flats or units may face additional difficulties. If cable isn't already installed in your building, getting it installed requires the cooperation of the body corporate or building manager.

Even in buildings where cable is already installed, depending on the type of equipment in place in your building, you may not be able to use cable as an Internet connection.

Unlike DSL a cable service is "shared". This means all subscribers on a given neighbourhood or node [a connection point] share a fixed amount of bandwidth. In theory the more people connected to a node, the slower it takes to download information off the Internet. In other words, a node accessed by only 250 people will generally provide a faster service than a node with 2000 users.

Cable companies have tricks to get around this. One of the cable operators, Optus, says its network is scaled (where more connection points are added) to suit the number of customers in a particular area of the network. Adding more connection points means they are able to rebalance the network so that customers in all areas of the network are receiving equal performance levels. Scaling the network is also known as "Node Grooming" and Optus says it carries out node grooms regularly.

Once the cable is installed, you'll need a cable modem to get connected. This connects at one end to the cable, and at the other end to your PC, either through an Ethernet or a USB connection. Cable modems can reach theoretical download speeds of up to 30Mbps. However, because cable is a shared medium with many other users on the same line, performance varies with the amount of subscribers using that particular stretch of bandwidth, as well as the usage patterns.

Most cable modems use Ethernet connections, and the cable company will be happy to sell you a network card as part of the installation if you don't already have one. (In fact, they prefer you to use the card they sell you, because they know it works well with the modem, even though -- in theory -- the modem should work with any card.) When the cable connection is installed, the technician will also load the required software on your PC. Software is available for all versions of Windows and for Mac OS, but not all providers have Mac software, so it's worth checking before you order. While there is no official support, it is theoretically possible to connect under Linux.

Optus uses a cable modem that is compliant with the DOCSIS (Data Over Cable Service Interface Specification) standard, which is the most common standard used worldwide. Previously, Telstra's HFC network required a Motorola Cyber-SURFR modem, which caused compatibility issues with some users. These were later replaced with DOCSIS 1.1 compliant modems. (DOCSIS is an open standard, and any manufacturer can make modems that support it.)

Cable download speeds are very fast, but, as usual, this can depend a great deal on the source from which the files are being downloaded. Ping times are also very fast, which is a boon for online games. However, as with the rest of the Internet, performance varies depending on the time of day and several other factors, such as the number of subscribers on the specific bandwidth strand.