Running Linux, 5th Edition

Cable Modems

When one wants Internet access enough, any wire will do. There are intensive experiments to use even the electricity grid to deliver Internet access. So it's not surprising that companies that built their business plans on delivering laser-crisp pictures of sporting events (the cable TV firms) would realize they could devote one of their channels to a local area network carrying digital data—hence the advent of cable Internet access.

The bandwidth on the cable infrastucture theoretically ranges up to 10 Mb (like an old Ethernet on coaxial cable), but some providers today achieve more throughput. Usually, they span a web of nodes, each of which offers 10 Mb or less. The neighbors who share the node have to share the bandwidth. So if there are two users on the node, each gets 5 Mb. Furthermore, some customers near the center (the central server, which is usually connected via the optical fiber cable to the rest of the Internet) have more bandwidth than those at the periphery. So check your cable network very carefully before you sign up for Internet access. Talk to the technical support first, and if they cannot answer your question, this might be a good indication about how good their support is going to be later.

ISPs that sell clients Internet access through cable modems will usually take responsibility for service all the way to your Ethernet card. They will give you a cable modem with a coaxial cable connected to their cable infrastructure, and an Ethernet (RJ45) connector ...