Ethernet over coax

Ethernet over Coax (EoC) is a family of technologies that supports the transmission of Ethernet frames over co-axial or coax cable.

History

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The first Ethernet standard, 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 Networks.

Research in Ethernet transmission over coaxial cable is still very active 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 most recently into Multiple Dwelling Unit (MDU) installations.

Local Area Networking and Home Networking

Most EoC technologies are being developed for in home or in premise networking. That is, they are expected to be operated within the domain of a single operator.

Metro and Broadband Carrier Networking

Some EoC technologies are being specifically developed for use by carriers, operators, and even enterprises, for the more complex operations that require hundreds of attached devices, provisioning, service management, etc.

Standards

IEEE 802.x

The Institute of Electrical and Electronics Engineers (IEEE) maintains all official Ethernet standards in the 802.x family or protocols.

IEEE 1394

Active work in Ethernet over Coax is ongoing in IEEE 1394 Trade Association (TA) developed based on the S400 standard.

Related Standards

ITU-T G.hn

The ITU-T 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 .

Non-Standard

MoCA

The Multimedia over Coax Alliance (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 Compatibility

The active EoC research and technology is focused on the use of existing CATV infrastructure for broadband (Internet) 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 of the frequency domain currently used for CATV or for satellite receiver to set-top box transmissions. Most of these operate in the frequency band from 2MHz to 1GHz. Thus most EoC technologies are designed to operate in bands above 1GHz. 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 550MHz or 750MHz. In those markets some EoC technologies focus on using spectrum between 550MHz or 750MHz and 1GHz. These systems will typically be lower cost, but could potentially conflict with future spectrum expansion up to 1GHz. In some markets there is a focus on using this 750MHz to 1GHz spectrum for EoC and specifically avoiding EoC bands above 1GHz because of potential ingress noise from over the air transmissions from cellular systems.

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