06-06-2017, 01:04 PM
In telecommunications, cable Internet access, abbreviated to cable Internet, is a form of broadband Internet access in which the infrastructure previously used only for cable television leads to digital Internet. Like the digital subscriber line and the fiber services facility, cable internet access provides network edge connectivity (last mile access) from the Internet service provider to an end user. It integrates into the cable television infrastructure in a manner analogous to DSL that uses the existing telephone network. Cable TV networks and telecommunications networks are the two predominant forms of residential Internet access. Recently, both have seen greater competition for fiber deployments, wireless and mobile networks.
Broadband cable Internet access requires a cable modem at the customer's premises and a cable termination system (CMTS) at a cable operator's facility, usually a cable TV header. The two are connected through a coaxial cable or a hybrid fiber coaxial (HFC) plant. Although access networks are sometimes referred to as last mile technologies, cable Internet systems can operate normally where the distance between the modem and the termination system is up to 160 kilometers. If the HFC network is large, the cable modem termination system can be grouped into hubs for efficient management.
Downstream, the direction to the user, bit rates can be as much as 400 Mbit / s for business connections, and 250 Mbit / s for residential service in some countries, although Gigabit speeds are becoming available. The traffic, which originates in the user, ranges from 384 kbit / s to more than 20 Mbit / s. A downstream channel can handle hundreds of cable modems. As the system grows, the CMTS can be upgraded with more downstream and upstream ports, and are grouped into hub CMTS for efficient management.
Most Data Cable Service Interface (DOCSIS) specification cable modems restrict upload and download rates, with customizable limits. These limits are set in configuration files that are downloaded to the modem using the Trivial File Transfer Protocol, when the modem establishes a connection to the provider's computer.
Broadband cable Internet access requires a cable modem at the customer's premises and a cable termination system (CMTS) at a cable operator's facility, usually a cable TV header. The two are connected through a coaxial cable or a hybrid fiber coaxial (HFC) plant. Although access networks are sometimes referred to as last mile technologies, cable Internet systems can operate normally where the distance between the modem and the termination system is up to 160 kilometers. If the HFC network is large, the cable modem termination system can be grouped into hubs for efficient management.
Downstream, the direction to the user, bit rates can be as much as 400 Mbit / s for business connections, and 250 Mbit / s for residential service in some countries, although Gigabit speeds are becoming available. The traffic, which originates in the user, ranges from 384 kbit / s to more than 20 Mbit / s. A downstream channel can handle hundreds of cable modems. As the system grows, the CMTS can be upgraded with more downstream and upstream ports, and are grouped into hub CMTS for efficient management.
Most Data Cable Service Interface (DOCSIS) specification cable modems restrict upload and download rates, with customizable limits. These limits are set in configuration files that are downloaded to the modem using the Trivial File Transfer Protocol, when the modem establishes a connection to the provider's computer.
It can be understood in the following video: