Data over cable service interface specification (DOCSIS) is a standard for broadband cable transmission of IP data services. It defines an upstream and downstream channel to enable bidirectional communications between a cable modem termination system (CMTS) in the cable headend and a subscriber's cable modem (CM).
Various versions of the standard have been established due to regional differences in cable TV bandwidth. The original American DOCSIS standard works with a 6 MHz channel bandwidth while the European EuroDOCSIS uses 8 MHz channels.
There have been five generations of the standard with ever increasing transmission rates since it was initially adopted in 1998: DOCSIS 1.0, 1.1, 2.0, 3.0 and DOCSIS 3.1. The latest generation, DOCSIS 3.1, was released in October 2013 and offers several significant improvements over its predecessors. The most important innovations include LDPC error correction, OFDM modulation and very wide channel bandwidths of up to 192 MHz in the downstream and up to 96 MHz in the upstream. The following table provides a comparative view of key parameters.
