SCTE 135-5-2022

DOCSIS 3.0 Part 5: Cable Modem to Customer Premise Equipment Interface

This interface specification is one of a family of interface specifications designed to facilitate the implementation of data services over Hybrid Fiber-Coax (HFC) cable networks, as well as over coaxial-only cable networks. Figure 5-1 provides the context for this specification in relation to the data over cable reference architecture and the other interface specifications in the family. This specification defines the interface requirements for data over cable services between a cable modem and the customer premise equipment (CPE). The CPE may include PCs, Macintoshes, workstations, network computers, and other electronic equipment. This specification defines the applicable communications standards and protocols as needed to implement a cable modem interface to the CPE. This specification is a replacement for [CMCI] and only applies to DOCSIS 3.0 (and forward) cable systems employing HFC (Hybrid Fiber Coax) and coaxial architectures. The primary changes from [CMCI] include:

  • Elimination of the Internal CPE Interfaces (like PCI) •
  • Elimination of the CPE Controlled Cable Modems (CCCM)
  • Addition of 100BASE-TX and 1000BASE-T interface options.

This specification:

  • Describes the communications protocols and standards to be employed
  • Specifies the data communication requirements and parameters that will be common to all units
  • Describes any additional application-unique interface requirements to ensure support for data-over-cable services.

This document specifies open protocols, with a preference for existing, well-known and well-accepted standards. This interface specification is written to provide the minimal set of requirements for satisfactory communication between the cable modem and CPE. "Cable Modem to Customer Premise Equipment Interface" (CMCI) is the general term used to describe this interface