Ethernet over coax
Encyclopedia
Ethernet over Coax is a family of technologies that supports the transmission of Ethernet
frames over coaxial cable
.
in the family of IEEE 802.3
, specified baseband
operation over coaxial cable. The use of coaxial cable for Ethernet is still supported by the standard, but rarely used because coaxial cable is more costly to purchase, install, and operate for Local Area Network
s.
Research in Ethernet transmission over coaxial cable continued, as both consumers and telecommunications operators strive to use existing coaxial cable (from Cable Television or CATV) installations, to carry broadband data into and through the home, and into Multiple Dwelling Unit (MDU) installations.
Most EoC technologies are being developed for in home or in premise networking and are expected to be operated within the domain of a single operator.
(IEEE) maintains all official Ethernet standards in the 802.x family or protocols.
Active work in Ethernet over Coax is ongoing in IEEE 1394 Trade Association (TA) developed based on the S400 standard.
G.hn
standard provides high-speed (up to 1 Gigabit/s) local area networking over existing home wires, including coaxial cable, power lines and phone lines. It defines an Application Protocol Convergence (APC) layer for encapsulation standard 802.3 Ethernet frames into G.hn MAC Service Data Units (MSDUs).
Other ITU-T standards for home networking over coaxial cable include G.9954, also known as HomePNA
3.1 .
(MoCA) is an industry alliance that develops specifications for home networking over coaxial cables. The MoCA specification is technically not a standard, because MoCA is not a recognized Standard Developing Organization
(SDO).
There are also proprietary EoC implementations using WiFi-like OFDM transmission.
(CATV) infrastructure for Internet access
or broadband data transmission. These technologies strive to be compatible with the existing CATV (or sometimes satellite television) broadcast signals that are simultaneously transmitted on the same cable. For this reason, the EoC technologies must operate outside the frequency domain
currently used for CATV or for satellite receiver to set-top box transmissions. Most such television systems operate in the frequency band from 2 MHz to 1 GHz; thus most EoC technologies are designed to operate in bands above 1 GHz. This is especially true for systems designed to operate in North America using the SCTE 55-1 and SCTE 55-2 CATV transmission systems. The same is true through most of Europe and portions of Asia. In many localities CATV systems operate only up to 550 MHz or 750 MHz. In those markets some EoC technologies focus on using spectrum between 550 MHz or 750 MHz and 1 GHz. These systems will typically be lower cost, but could potentially conflict with future spectrum expansion up to 1 GHz. In some markets there is a focus on using this 750 MHz to 1 GHz spectrum for EoC and specifically avoiding EoC bands above 1 GHz because of potential ingress noise from over the air transmissions from cellular systems.
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
frames over coaxial cable
Coaxial cable
Coaxial cable, or coax, has an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis...
.
History
The first Ethernet standard, known as 10BASE510BASE5
10BASE5 was the original commercially available variant of Ethernet.For its physical layer it used cable similar to RG-8/U coaxial cable but with extra braided shielding. This is a stiff, diameter cable with an impedance of 50 ohms , a solid center conductor, a foam insulating filler, a shielding...
in the family of IEEE 802.3
IEEE 802.3
IEEE 802.3 is a working group and a collection of IEEE standards produced by the working group defining the physical layer and data link layer's media access control of wired Ethernet. This is generally a local area network technology with some wide area network applications...
, specified baseband
Baseband
In telecommunications and signal processing, baseband is an adjective that describes signals and systems whose range of frequencies is measured from close to 0 hertz to a cut-off frequency, a maximum bandwidth or highest signal frequency; it is sometimes used as a noun for a band of frequencies...
operation over coaxial cable. The use of coaxial cable for Ethernet is still supported by the standard, but rarely used because coaxial cable is more costly to purchase, install, and operate for Local Area Network
Local area network
A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...
s.
Research in Ethernet transmission over coaxial cable continued, as both consumers and telecommunications operators strive to use existing coaxial cable (from Cable Television or CATV) installations, to carry broadband data into and through the home, and into Multiple Dwelling Unit (MDU) installations.
Most EoC technologies are being developed for in home or in premise networking and are expected to be operated within the domain of a single operator.
Standards
The Institute of Electrical and Electronics EngineersInstitute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers is a non-profit professional association headquartered in New York City that is dedicated to advancing technological innovation and excellence...
(IEEE) maintains all official Ethernet standards in the 802.x family or protocols.
Active work in Ethernet over Coax is ongoing in IEEE 1394 Trade Association (TA) developed based on the S400 standard.
ITU-T G.hn
The ITU-TITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
G.hn
G.hn
G.hn is the common name for a home network technology family of standards developed under the International Telecommunication Union's Standardization arm and promoted by the HomeGrid Forum...
standard provides high-speed (up to 1 Gigabit/s) local area networking over existing home wires, including coaxial cable, power lines and phone lines. It defines an Application Protocol Convergence (APC) layer for encapsulation standard 802.3 Ethernet frames into G.hn MAC Service Data Units (MSDUs).
Other ITU-T standards for home networking over coaxial cable include G.9954, also known as HomePNA
HomePNA
The HomePNA Alliance is an incorporated non-profit industry association of companies that develops and standardizes technology for home networking over the existing coaxial cables and telephone wiring within homes.-Overview:HomePNA does not manufacture products, although its members do...
3.1 .
MoCA
The Multimedia over Coax AllianceMultimedia over Coax Alliance
Multimedia over Coax Alliance is a trade group promoting a standard that uses coaxial cables to connect consumer electronics and home networking devices in homes. It allows both data communication and the transfer of audio and video streams....
(MoCA) is an industry alliance that develops specifications for home networking over coaxial cables. The MoCA specification is technically not a standard, because MoCA is not a recognized Standard Developing Organization
Standards organization
A standards organization, standards body, standards developing organization , or standards setting organization is any organization whose primary activities are developing, coordinating, promulgating, revising, amending, reissuing, interpreting, or otherwise producing technical standards that are...
(SDO).
There are also proprietary EoC implementations using WiFi-like OFDM transmission.
CATV compatibility
EoC research and technology is focused on the use of existing cable televisionCable television
Cable television is a system of providing television programs to consumers via radio frequency signals transmitted to televisions through coaxial cables or digital light pulses through fixed optical fibers located on the subscriber's property, much like the over-the-air method used in traditional...
(CATV) infrastructure for Internet access
Internet access
Many technologies and service plans for Internet access allow customers to connect to the Internet.Consumer use first became popular through dial-up connections in the 20th century....
or broadband data transmission. These technologies strive to be compatible with the existing CATV (or sometimes satellite television) broadcast signals that are simultaneously transmitted on the same cable. For this reason, the EoC technologies must operate outside the frequency domain
Frequency domain
In electronics, control systems engineering, and statistics, frequency domain is a term used to describe the domain for analysis of mathematical functions or signals with respect to frequency, rather than time....
currently used for CATV or for satellite receiver to set-top box transmissions. Most such television systems operate in the frequency band from 2 MHz to 1 GHz; thus most EoC technologies are designed to operate in bands above 1 GHz. This is especially true for systems designed to operate in North America using the SCTE 55-1 and SCTE 55-2 CATV transmission systems. The same is true through most of Europe and portions of Asia. In many localities CATV systems operate only up to 550 MHz or 750 MHz. In those markets some EoC technologies focus on using spectrum between 550 MHz or 750 MHz and 1 GHz. These systems will typically be lower cost, but could potentially conflict with future spectrum expansion up to 1 GHz. In some markets there is a focus on using this 750 MHz to 1 GHz spectrum for EoC and specifically avoiding EoC bands above 1 GHz because of potential ingress noise from over the air transmissions from cellular systems.