Before Fiber: DSL & Cable
Digital Subscriber Line (DSL) used the existing telephone lines to transmit data, which were usually made of copper. DSL is being phased out for the most part in favor of cable or wireless. DSL bandwidth speeds range from 1-18 Mbps.
Cable internet uses coaxial cable, also made from copper, and is generally bundled with the same cables used to run the television network. This is why many cable providers offer bundled plans with a TV subscription and Internet access. The average speed for cable varies but ranges from around 20 Mbps to 600 Mbps.
Fiber optic cables use small glass fibers to transmit data using pulses of light. The light travels much like electricity would through a copper wire, but the advantage is that fiber cables can carry multiple signals at once. They’re incredibly small, so they’re often bundled into larger cables called “fiber optic trunk cables,” each containing multiple fiber lines. Fiber cables carry huge amounts of data, and the average speed that you’ll see at your house is around 1 Gbps (often called “gigabit internet”).
Fiber trunk cables form most of the backbone of the modern internet, and you’ll see the benefits of them even if you don’t have “fiber internet.” This is because the Internet Exchange Points (IXPs)—the switching and routing stations that connect your house to the rest of the world—use fiber optic trunk lines to connect to other IXPs.
When it comes time to connect all the houses in the city to your local IXP (a run usually referred to as “the last mile”), infrastructure is limited, and expensive fiber buildout costs can be economically prohibitive for your service provider. Until fiber construction is completed, consumers will continue to rely on traditional copper, coaxial cable, or wireless Internet connections to your house. This run becomes the bottleneck for your internet speed. When someone says they have “fiber internet,” what they mean is that the connection from their house to the IXP is also using fiber, eliminating the speed limit of copper cable.
The Limits of Fiber
There’s a reason fiber Internet isn’t common—cost. Fiber is a lot more expensive to run and doesn’t justify the cost when cable lines are often already available. For most people, the 20-100 Mbps speed they get on cable or wireless is enough, as most downloads from the internet aren’t going to max out that connection anyway.
Your speed is only as good as the weakest link. While fiber is certainly better than copper, a lot of times you won’t see an increase in actual download speeds because of limits on the server from which you’re downloading. An app like Steam downloading a 10 GB game seems like it would take only a few seconds on 1000 Mbps fiber connection, but in reality you’ll only get around 50 Mbps maximum speed from Steam’s servers.
If you’re using an application that can take advantage of the increased speed, or have multiple computers in the house, then fiber might be a good option for you. Right now, though, it remains a service only available in a few select cities.