DOCSIS® — FAQs
What is the CableLabs Certified Cable Modem project?
The CableLabs Certified Cable Modem Project, also known as DOCSIS®, concurrently (Data-Over-Cable Service Interface Specifications), continuously offers innovation to the cable broadband high speed Internet access industry. The initiative provides laboratory testing which enables certification of cable modems and qualification of CMTSs (cable modem termination systems), thereby enabling interoperability among vendor products. The project also defines interface requirements for cable modems involved in high-speed data distribution over cable television system networks. It provides cable modem equipment suppliers with a fast, market-oriented method for attaining cable industry acknowledgement of DOCSIS® compliance and has resulted in high-speed modems being certified for retail sale. Overall, the project is a key component of the drivers that have resulted in a multi billion dollar cable broadband industry.
MSOs require interoperability among DOCSIS® modems. While no CableLabs member company is required to purchase DOCSIS® modems, the majority of modems purchased are DOCSIS® certified. As of October 2007, more than 35 million DOCSIS® cable modems had been deployed worldwide.
What are the objectives of the project?
The objectives of the Certified Cable Modem Project include enabling the cable industry to rapidly develop and deploy innovative broadband technologies by establishing the necessary set of communications and operations support interface specifications for cable modems and associated equipment. The specifications are intended to be non-vendor specific, allowing cross-manufacturer compatibility and rapid time to market for manufacturers of high-speed data communications services over two-way hybrid-fiber/coax (HFC) cable television systems.
What is a Data Over Cable System?
A data over cable system adds to a cable television system a high-speed data communications path that is transparent to the Internet Protocol (IP), between subscriber locations and the cable operator's headend.
The data over cable system includes not only the data communications elements but also the needed operations and business support elements for security, configuration, performance, fault, and accounting management.
The cable modem typically is connected to a two-way cable RF path over a low-split HFC cable system. Thus, in the downstream direction (toward the subscriber), the cable modem receives signals in a predefined portion of the downstream passband, which will be between 93 MHz and a system-dependent upper limit that could be as high as 870MHz. In the upstream direction (away from the subscriber), the cable modem would transmit signals in a predefined portion of the upstream passband, which will be between 5 MHz and 42 MHz.
Why does this project exist and what are the benefits?
The cable industry has spent more than $100 billion over the past decade to operatecable plants that provide reliable two-way broadband connectivity to meet the explosive consumer demand for access to the Internet. Many cable operators have affiliated operations with valuable content and applications that can be offered via local multimedia servers. All of these applications would benefit by high-speed, economical, connectionless data services between homes and businesses and a point of concentration such as a cable headend.
The cable industry has proven that it is in a unique position to rapidly offer these high-speed data services. This project is designed to continuously innovate on behalf of cable operators and to advance the development of well-accepted open interface specifications.
The benefits of an open, well-accepted set of specifications will accrue to cable operators, vendors and consumers. For consumers, this effort enables rapid deployment of innovative technologies, as well as lower price points for broadband services; for cable operators, these specifications enable compatible products to be sourced from multiple vendors in a timely fashion, thereby, unlocking the revenue potential of the service. And, for vendors, the specifications reduce development risk, resulting in the ability to invest in high-level integration of cost reducing semiconductor devices, and rapidly build market volume to grow the industry.
Does CableLabs sell cable modems?
CableLabs does not market or sell cable modems. Please refer to our list of certified vendors, or contact your service provider directly.
What is a cable modem?
A cable modem is a device that allows high-speed access to the Internet via a cable TV network. A cable modem will typically have two connections, one to the cable wall outlet and one to a computer.
Cable modems allow consumers access to the Internet at higher speeds and at a fraction of the time it takes traditional dial-up telephone modems. This is true for two reasons: 1) broadband networks make the connection up to a hundred times faster, and 2) the service is "always on," meaning customers get the information they want, when they want it. Unlike telephone modems, cable modems allow consumers to keep their telephone lines open for voice conversations.
Cable modems are "certified" interoperable with each other. Certification provides the retail customer with the assurance that the cable modem complies with the DOCSIS® specification and will interoperate with other certified modems and qualified headend systems.
How secure are cable modems?
The DOCSIS® specifications provide a baseline privacy that guarantees user data privacy (across the cable network) and services protection by encrypting CM/CMTS traffic flows and controlling distribution of encryption keys to CMs. The DOCSIS® system architecture includes security components that ensure user data privacy across the shared-medium cable network and prevents unauthorized access to DOCSIS®-based data transport services across the cable network. The DOCSIS® architecture also supports the policing (e.g., filtering) functions that can be used to reduce risks from attacks targeted at attached CPE devices. These policing capabilities are comparable to those available within dedicated line network access systems (e.g.; telephone, ISDN, DSL).
What is a CMTS and how does it relate to a cable modem?
The cable modem termination system (CMTS) is the unit that is purchased by and resides at the cable operator's facility, and acts as the connection between the cable network and the outside network. CMTSs are termed "qualified" when they pass an interoperability test procedure similar to the modems. Qualification ensures the cable operator or a broadband service provider that the headend equipment will interoperate with certified cable modems. Please see our list of DOCSIS®-Qualified CMTSs.
Can a consumer buy a modem that is not certified?
Yes. The specification was developed to provide consumers with a high degree of confidence that their off-the-shelf modem will function compatibly with their cable operator's headend. Vendor participation is voluntary, but the benefit to the vendor's sales and marketing efforts is obvious. Non-certified modems are available from some stores and operators in regions of the country, but those modems may not work if purchased and then transported to other regions of the country.
How do consumers know a cable modem will work on the cable system in their town?
If you have doubts about whether your cable system operator can support CableLabs Certified modems, check with your local retailer or call your local cable system operator.
What is happening to existing proprietary cable modem deployments?
Cable operators may continue to provide their existing proprietary modem service, or they may replace their proprietary service with DOCSIS® service, or operate both together in the same system.
Whom should customers contact when a modem doesn't work?
If they lease a modem, they should contact their local cable operator. If they purchased a CableLabs Certified modem, they should call their local cable operator and if it is determined that the problem is with the modem and not with the service, they will be asked to contact the retailer or modem manufacturer.
Where do I buy a CableLabs Certified cable modem?
Cable modems can be purchased from retail stores, on-line, or financed through third-parties, or leased through cable operators.
If I have a non-certified cable modem, do I need to replace it with a CableLabs Certified modem?
As your cable operator transitions individual neighborhoods to CableLabs certified equipment, you will be contacted. In the meantime, your modem will operate as it always has.
How does a modem or CMTS become DOCSIS® Certified/Qualified?
After a vendor is satisfied that its product meets CableLabs Certified specifications, it applies to participate in a pre-scheduled certification wave activity. During the certification wave, CableLabs' staff engineers perform a series of audit tests over a period of several weeks. The data is gathered and provided to the Certification Board, which is comprised of cable operators, The board reviews the test data to determine whether the product meets the requirements of the CableLabs specifications so as to become CableLabs Certified or Qualified. The Certification Board makes its recommendation to the Executive Committee of the CableLabs Board of Directors for final approval.
If a product isn't certified in one wave, can it be submitted again?
Yes. The process is designed to certify as many vendors as can demonstrate that they have achieved the level of quality, stability and interoperability required by the DOCSIS® specification. In that way, a consumer can count on the consistency and interoperability of the cable modem when he or she purchases a product carrying the CableLabs Certified seal. As to when a cable modem is submitted to CableLabs for certification testing, each vendor needs to make its own decision based on product readiness.
CableLabs does go over the results in detail, with each vendor, to provide the vendors with the information they need in order to pass.
CableLabs performs numerous certification waves per year. Please review the DOCSIS® Certification Wave Schedule for more information about when these waves occur.
A product may be submitted to a certification wave, for DOCSIS® 1.0, DOCSIS® 1.1, DOCSIS® 2.0, or DOCSIS® 3.0 on the dates listed. The certification wave guidelines go into great detail about submission requirements, fees, and processes.
What other projects are being developed within the DOCSIS® Project?
In addition to the further development and testing of DOCSIS 3.0 devices, Business Services related specifications are currently being developed within the DOCSIS® Project.
What are the key differences between DOCSIS® 2.0 and 3.0?
DOCSIS® 2.0 and 3.0 specifications are available from the Specifications navigation on the DOCSIS® Web site.DOCSIS® 3.0 builds upon DOCSIS® 2.0, and provides all of the features and functionality that DOCSIS® 2.0 provides. In addition, it provides the following enhancements:
- Channel bonding to increase possible upstream and downstream data rates by a factor of 4 or more
- Support for IPv6
- Enhanced security features, including the Advanced Encryption Standard
- Support for IPTV
- Support for HFC systems other than low-split
- Enhanced reporting to manage traffic
- Enhanced tools to detect plant problems
What are the key differences between DOCSIS® 1.1 and 2.0?
DOCSIS® 1.1 and 2.0 specifications available from the Specifications navigation on the DOCSIS® Web site.DOCSIS® 2.0 builds upon DOCSIS® 1.1, and provides all of the features and functionality that DOCSIS® 1.1 provides. In addition, it provides the following enhancements:
- Significantly enhanced upstream capacity
- 6.4 MHz maximum upstream channel width
- 27 Mbps maximum upstream channel capacity
- Synchronous-CDMA operation
- Increased robustness to upstream noise and channel impairments
- Enhanced Reed-Solomon error correction
- Trellis Coded Modulation
- Channel utilization statistics
What are the key differences between DOCSIS® 1.0 and 1.1?
DOCSIS® 1.0 and 1.1 specifications available from the Specifications navigation on the DOCSIS® Web site.To summarize, DOCSIS® 1.1 builds upon 1.0, but also includes the following features:
- Quality of Service
- Dynamic Services
- Payload Header Suppression
- IP Multicast
- CM Authentication
- View-based access control and management (VACM)
- CM Account Management
- Fault Management
- Secure Software
What is CCCM?
The CCCM project is covered under the DOCSIS® CMCI Specification.
It provides an architectural overview of a CPE Controlled Cable Modem (CCCM), introducing the basic functions residing in both the CCCM hardware and the CCCM software running on the host CPE.
How can I get a login and password to the CableModem DocZone Area?
In order to gain access to the CableModem DocZone area, a vendor must submit the DOCSIS® Non-Disclosure Agreement (NDA). Information on how to participate in the DOCSIS® project is available on the How to Participate page on the DOCSIS® Web site. The NDA also allows a vendor to subscribe to technical e-mail reflectors, attend vendor meetings, and to get involved in project working groups.
How can I get more information?
Please contact us for more information.