An Internet user’s experience is dependent on the applications he or she uses on the Internet, and these work the same regardless of whether the user has a DSL or fiber connection from a traditional telecommunications provider or an Internet connection provided by a cable company. However, the similarity of experience belies significant technical differences between the two types of networks.
The fundamental difference between these network types is in the way they make the final connection to users, commonly referred to as the “last mile.” While a phone company provides an individual connection for each user, hundreds of cable customers typically share a single connection, a network architecture called “shared last-mile.”
This is a legacy of the time when cable delivered exactly the same content to every household. Significant changes to the core of cable networks has allowed them to offer some individual content, such as on-demand video and Internet access, but the amount of data users can send back to the cable company–including uploading content on a P2P network–over their shared connection is very limited.
Hence, the greatest impact P2P use has on a cable provider is when all of the upload capacity available for an entire neighborhood is consumed by a handful of Internet users.
With currently deployed technologies and the service packages offered by cable companies, as few as 10 percent of the users on a shared connection can consume 100 percent of the available upload bandwidth.
The latest cable Internet access standard, DOCSIS 3.0, is being deployed by some cable providers to help address this issue. But pressure from telecoms rolling out fiber-optic connections to homes may force cable companies to continue increasing the bandwidth available to each user, eliminating or reducing the benefits of the new technology.
— Christopher Petro