Cable Internet access

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In telecommunications, cable Internet access, shortened to cable Internet, is a form of broadband internet access which uses the same infrastructure as cable television. Like digital subscriber line (DSL) and fiber to the premises, cable Internet access provides network edge connectivity (last mile access) from the Internet service provider to an end user. It is integrated into the cable television infrastructure analogously to DSL, which uses the existing telephone network. Cable TV networks and telecommunications networks are the two predominan forms of residential Internet access. Recently,[ when? ] both have seen increased competition from fiber deployments, wireless, and satellite internet access.

Contents

Hardware and bit rates

Broadband cable Internet access requires a cable modem at the customer's premises and a cable modem termination system (CMTS) at a cable operator facility, typically a cable television headend. The two are connected via coaxial cable to a hybrid fibre-coaxial (HFC) network. While access networks are referred to as last-mile technologies, cable Internet systems can typically operate where the distance between the modem and the termination system is up to 160 kilometres (99 mi). If the HFC network is large, the cable modem termination system can be grouped into hubs for efficient management. Several standards have been used for cable internet, but the most common is Data Over Cable Service Interface Specification (DOCSIS). [1]

A cable modem at the customer is connected via coaxial cable to an optical node, and thus into an HFC network. An optical node serves many modems as the modems are connected with coaxial cable to a coaxial cable "trunk" via distribution "taps" on the trunk, which then connects to the node, possibly using amplifiers along the trunk. The optical node converts the radio frequency (RF) signal in the coaxial cable trunk into light pulses to be sent through optical fibers in the HFC network. At the other end of the network, an optics platform or headend platform converts the light pulses into RF signals in coaxial cables again using transmitter and receiver modules, [2] [3] and the cable modem termination system (CMTS) connects to these coaxial cables. An example of an optics platform is the Arris CH3000. There are two coaxial cables at the CMTS for each node: one for the downstream (download speed signal), and the other for the upstream (upload speed signal). [3] The CMTS then connects to the ISP's IP (Internet Protocol) network. [4]

Downstream, the direction toward the user, bit rates can be as high as 1 Gbit/s. [5] Upstream traffic, originating at the user, ranges from 384 kbit/s to more than 50 Mbit/s, although maximum effective range seems to be unknown. One downstream channel can handle hundreds of cable modems. As the system grows, the CMTS can be upgraded with more downstream and upstream ports, and grouped into hub CMTSs for efficient management.

Most DOCSIS cable modems restrict upload and download rates, with customizable limits. These limits are set in configuration files which are downloaded to the modem using the Trivial File Transfer Protocol, when the modem first establishes a connection to the provider's equipment. [6] Some users [ specify ] have attempted to override the bandwidth cap and gain access to the full bandwidth of the system by uploading their own configuration file to the cable modem, a process called uncapping.

Shared bandwidth

In most residential broadband technologies, such as cable Internet, DSL, satellite internet, or wireless broadband, a population of users share the available bandwidth. Some technologies share only their core network, while some including cable internet and passive optical network (PON) also share the access network. This arrangement allows the network operator to take advantage of statistical multiplexing, a bandwidth sharing technique which is employed to distribute bandwidth fairly, in order to provide an adequate level of service at an acceptable price. However, the operator has to monitor usage patterns and scale the network appropriately, to ensure that customers receive adequate service even during peak-usage times. If the network operator does not provide enough bandwidth for a particular neighborhood, the connection would become saturated and speeds would drop if many people are using the service at the same time, or drop out completely. Operators have been known to use a bandwidth cap, or other bandwidth throttling technique; users' download speed is limited during peak times, if they have downloaded a large amount of data that day. [7]

See also

Related Research Articles

<span class="mw-page-title-main">Cable television</span> Television content transmitted via signals on coaxial cable

Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with broadcast television, in which the television signal is transmitted over-the-air by radio waves and received by a television antenna, or satellite television, in which the television signal is transmitted over-the-air by radio waves from a communications satellite and received by a satellite dish on the roof. FM radio programming, high-speed Internet, telephone services, and similar non-television services may also be provided through these cables. Analog television was standard in the 20th century, but since the 2000s, cable systems have been upgraded to digital cable operation.

Digital subscriber line is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric digital subscriber line (ADSL), the most commonly installed DSL technology, for Internet access.

<span class="mw-page-title-main">Cable modem</span> Broadband Internet access device

A cable modem is a type of network bridge that provides bi-directional data communication via radio frequency channels on a hybrid fiber-coaxial (HFC), radio frequency over glass (RFoG) and coaxial cable infrastructure. Cable modems are primarily used to deliver broadband Internet access in the form of cable Internet, taking advantage of the high bandwidth of a HFC and RFoG network. They are commonly deployed in the Americas, Asia, Australia, and Europe.

<span class="mw-page-title-main">Broadband</span> Data transmission concept

In telecommunications, broadband or high speed is the wide-bandwidth data transmission that exploits signals at a wide spread of frequencies or several different simultaneous frequencies, and is used in fast Internet access. The transmission medium can be coaxial cable, optical fiber, wireless Internet (radio), twisted pair cable, or satellite.

<span class="mw-page-title-main">DSLAM</span> Network device that connects DSL interfaces to a digital communications channel

A digital subscriber line access multiplexer is a network device, often located in telephone exchanges, that connects multiple customer digital subscriber line (DSL) interfaces to a high-speed digital communications channel using multiplexing techniques. Its cable internet (DOCSIS) counterpart is the cable modem termination system.

Data Over Cable Service Interface Specification (DOCSIS) is an international telecommunications standard that permits the addition of high-bandwidth data transfer to an existing cable television (CATV) system. It is used by many cable television operators to provide cable Internet access over their existing hybrid fiber-coaxial (HFC) infrastructure.

<span class="mw-page-title-main">Internet access</span> Individual connection to the Internet

Internet access is a facility or service that provides connectivity for a computer, a computer network, or other network device to the Internet, and for individuals or organizations to access or use applications such as email and the World Wide Web. Internet access is offered for sale by an international hierarchy of Internet service providers (ISPs) using various networking technologies. At the retail level, many organizations, including municipal entities, also provide cost-free access to the general public. Types of connections range from fixed-line cable to mobile and satellite.

<span class="mw-page-title-main">Cable television headend</span> Facility for cable television system

A cable television headend is a master facility for receiving television signals for processing and distribution over a cable television system. A headend facility may be staffed or unstaffed and is typically surrounded by some type of security fencing. The building is typically sturdy and purpose-built to provide security, cooling, and easy access for the electronic equipment used to receive and re-transmit video over the local cable infrastructure. One can also find head ends in power-line communication (PLC) substations and Internet communications networks.

Hybrid fiber-coaxial (HFC) is a broadband telecommunications network that combines optical fiber and coaxial cable. It has been commonly employed globally by cable television operators since the early 1990s.

<span class="mw-page-title-main">Cable modem termination system</span> Equipment used to provide high speed data services

A cable modem termination system is a piece of equipment, typically located in a cable company's headend or hubsite, which is used to provide data services, such as cable Internet or Voice over IP, to cable subscribers.

<span class="mw-page-title-main">Passive optical network</span> Technology used to provide broadband to the end consumer via fiber

A passive optical network (PON) is a fiber-optic telecommunications network that uses only unpowered devices to carry signals, as opposed to electronic equipment. In practice, PONs are typically used for the last mile between Internet service providers (ISP) and their customers. In this use, a PON has a point-to-multipoint topology in which an ISP uses a single device to serve many end-user sites using a system such as 10G-PON or GPON. In this one-to-many topology, a single fiber serving many sites branches into multiple fibers through a passive splitter, and those fibers can each serve multiple sites through further splitters. The light from the ISP is divided through the splitters to reach all the customer sites, and light from the customer sites is combined into the single fiber. Many fiber ISPs prefer this system.

<span class="mw-page-title-main">Triple play (telecommunications)</span> Bundling of television, internet, and telephone service

In telecommunication, triple play is the provision of broadband internet, television, and telephony over a single connection. This approach emphasizes the supplier convergence of multiple services, aiming to enhance user convenience and streamline service delivery.

Fiber to the <i>x</i> Broadband network architecture term

Fiber to the x or fiber in the loop is a generic term for any broadband network architecture using optical fiber to provide all or part of the local loop used for last mile telecommunications. As fiber optic cables are able to carry much more data than copper cables, especially over long distances, copper telephone networks built in the 20th century are being replaced by fiber.

Cable Television Laboratories, Inc. (CableLabs) is a nonprofit corporation promoting innovation as a research and development lab founded in 1988 by American cable operators. System operators from around the world are eligible to be members.

In telecommunications, radio frequency over glass (RFoG) is a deep-fiber network design in which the coax portion of the hybrid fiber coax (HFC) network is replaced by a single-fiber passive optical network (PON). Downstream and return-path transmission use different wavelengths to share the same fiber. The return-path wavelength standard is expected to be 1610 nm, but early deployments have used 1590 nm. Using 1590/1610 nm for the return path allows the fiber infrastructure to support both RFoG and a standards-based PON simultaneously, operating with 1490 nm downstream and 1310 nm return-path wavelengths.

Com21, Inc., was an early pioneer in developing cable modem networks in the era before the standard DOCSIS was introduced for Internet access via cable television networks. The company filed for bankruptcy in 2003.

Subisu Cablenet Ltd. is a Nepalese Internet Service Provider company located in Kathmandu, Nepal, and was established in 2001. Subisu employs over 1500 full-time employees, of which around 900 are technical and around 700 are non-technical. As of 2023, the company has over 235,000 customers. It has coverage in all 77 districts of Nepal. Subisu primarily provides cable and fiber internet and digital TV services through a hybrid fiber-coaxial (HFCC) network.

<span class="mw-page-title-main">G.fast</span> ITU-T Recommendation

G.fast is a digital subscriber line (DSL) protocol standard for local loops shorter than 500 meters, with performance targets between 100 Mbit/s and 1 Gbit/s, depending on loop length. High speeds are only achieved over very short loops. Although G.fast was initially designed for loops shorter than 250 meters, Sckipio in early 2015 demonstrated G.fast delivering speeds over 100 Mbit/s at nearly 500 meters and the EU announced a research project.

<span class="mw-page-title-main">Ziggo</span> Dutch cable operator

Ziggo Holding B.V. is the largest cable operator in the Netherlands, providing digital cable television, Internet, and telephone service to both residential and commercial customers.

Inter is a Venezuelan television broadcaster and telecommunications provider headquartered in Barquisimeto, Lara, Venezuela. Inter was founded in 1996 as InterCable. Its fiscal name is Corporacion Telemic C.A, and its main shareholder is the investment fund HM Capital Partners.

References

  1. Palmer, Michael (21 June 2012). Hands-On Networking Fundamentals. ISBN   978-1285402758.
  2. On The Design of Hybrid Fiber-Coax Networks
  3. 1 2 Data-Over-Cable Service Interface Specifications DOCSIS® 3.1 CCAP™ Operations Support System Interface Specification CM-SP-CCAP-OSSIv3.1-I25-220819. Cable labs.
  4. Data-Over-Cable Service Interface Specifications DOCSIS® 4.0 Physical Layer Specification CM-SP-PHYv4.0-I06-221019. Cablelabs.
  5. Friend, David (October 5, 2015). "Rogers, Bell and Telus hike Internet speeds, prices with 'gigabit' service". Toronto Star . The Canadian Press. Retrieved May 12, 2016.
  6. Ferri, Vic. "Cable Internet-Are You Being Capped?". TechTrax. Using the Internet. MouseTrax Computing Solutions. Archived from the original on February 24, 2012. Retrieved May 12, 2016.
  7. Aughton, Simon (May 8, 2007). "Virgin Media cuts broadband speeds for heavy downloaders". PC Pro. Retrieved May 12, 2016.[ better source needed ]