Types of Access Networks: Cable, FTTH, Dial-Up, and Satellite

Cable Internet #

• In the case of cable Internet, the TV cable company is the ISP and it relies on the preexisting infrastructure of cable TV to grant Internet access.
• It runs on coaxial cable. Coaxial cable has enough of a frequency range to carry TV channels and a stream of upstream and downstream Internet.

How It Works #

• In essence, cable Internet works very similarly to DSL.
• A device on both the user’s end and the ISP’s end modulates the analog signals to digital and vice versa.

Slower During Peak Hours #

However, cable Internet can be slower during peak hours, when a majority of users are online at once. This is because cable Internet is a shared broadcast medium: every signal that comes from the ISP is sent to every single home regardless of which one it was meant for.

Hybrid Fiber Coax #

Usually, cable Internet works with a combination of coaxial cable and optic fiber (which we’ll discuss in the next chapter), where the fiber connects optical nodes that exist in every neighborhood to the ISP and coaxial cable further connects the nodes to the houses. This is sometimes referred to as a hybrid fiber coax (HFC). Have a look at the figure below to see how hybrid fiber coax works.