Data Over Cable Service Interface Specification (DOCSIS)

Data Over Cable Service Interface Specification (DOCSIS) is an international standard developed by Cable Labs and contributing companies that include: ARRIS, Big Band Networks, Broad com, Cisco, Conexant, Correlant, Intel, Motorola, Netgear, Terayon, and Texas Instruments. DOCSIS defines the communications and operation support interface requirements for a data over cable system. It permits the addition of high-speed data transfer to an existing Cable TV (CATV) system. It is employed by many cable television operators to provide Internet access (see cable Internet) over their existing hybrid fiber coaxial (HFC) infrastructure.

The first DOCSIS specification was version 1.0, issued in March of 1997, with revision 1.1 (adding Quality of Service (QoS) capabilities) following in April of 1999. Because of increased demand for symmetric services such as IP telephony, DOCSIS was revised to enhance upstream transmission speeds; DOCSIS 2.0 was released in December 2001. Most recently, the specification was revised to significantly increase transmissions speeds (this time both upstream and downstream) and introduce support for Internet Protocol version 6 (IPv6).

This version, DOCSIS 3.0, was released in August 2006. Cross-version compatibility has been maintained across all versions of DOCSIS, with the devices falling back to the highest supported version in common between both endpoints (cable modem and cable modem termination system).