To see the full list of certified cable modems, click here.
MCNS
MCNS, a consortium of North American MSOs, CableLabs and Arthur D. Little, developed a specification known as DOCSIS for transmitting data over a cable network. The specification was embraced by the SCTE and submitted to the ITU in March of 1998, where it was approved as an international standard for data over cable networking.
Later in the year, CableLabs established a certification program, in which it required vendors to pass a series of interoperability tests before receiving official DOCSIS certification. Late last year, several vendors entered products into the certification process.
The industry expected that modems would be certified before the end of the year. However, due to the complexities of establishing interoperability among the first group of entrants and the presence of ongoing modifications to the spec during the certification process, there were no modems certified through January of 1999. Certified modems are now expected towards the end of the first quarter.
While waiting for stamps, vendors are already fervently working on future generation DOCSIS networks. Although the specification for DOCSIS 1.1 has not been finalized, certified products are expected in the third quarter of this year. The specification will support fragmentation in the upstream and downstream, allowing providers to offer tiered services and support QoS reliant applications.
Also, Broadcom and Terayon are working with the MCNS gang to implement an IEEE 802.14 endorsed advanced PHY technology into the DOCSIS spec. The emerging standard will be known as DOCSIS 1.2. The technology will provide a more robust upstream and enable support for more business class applications. Certified products are expected in Q'4 of this year or early Y2K.
DOCSIS specifications
Cable Modem Vendors (chart denotes which vendors are planning to develop DOCSIS networks or products)
CableLabs
IEEE 802.14
The IEEE 802.14 Working Group is a committee of engineers representing the vendor community that has developed a specification for data over cable networking. The group, which was formed in the early 90's, had intended to develop a spec that would be recognized as an international standard. However, MCNS' effort undermined the group's work and was able to define a spec much quicker than the IEEE.
Despite ITU recognition of DOCSIS as an international standard last year, the IEEE 802.14 continued to work on its specification. In an effort to acknowledge the Working Group's work, MCNS indicated that it would implement IEEE 802.14's advanced PHY specification within DOCSIS - a partial victory for the group. In meeting that commitment, MCNS asked Broadcom and Terayon to develop the advanced PHY for DOCSIS 1.2, the same duo that IEEE had awarded the privilege to develop an advanced PHY for its own spec.
Some IEEE committee members were pleased with MCNS' recognition. However, a few group leaders felt slighted. These leaders believed that MCNS would appoint the Working Group as an entity to author the advanced PHY spec. Instead, the two vendors were exclusively appointed.
The future of the IEEE 802.14 spec is unknown. At one time, it was believed that it would be a standard for operators outside North America. At another time, the industry expected the specification to apply to corporate data services, while DOCSIS would be deployed for residential services. Today, these prospects seem unlikely.
It is possible that a small set of vendors outside of the U.S. will build to the IEEE spec. In late 1997, a couple of vendors developed networks based on the emerging specification. However, both vendors are now working on networks outside of the spec.
In all, the IEEE 802.14 effort was a failure. For its work, it received a half-baked consolation prize from MCNS and very little vendor and provider support. The group had good intentions and its specification was undoubtedly a better technological than that developed by MCNS. However, with all that we do, timing is everything and the if the group had one downfall, it was its inability to develop a spec in a short amount of time.
IEEE 802.14 Draft 2 Revision 2
Minutes from select IEEE 802.14 meetings
An Update on the Activities of IEEE 802.14 Working Group Contributed by Robert Russell & Roger Durand (12/98)
DAVIC/DVB (EuroModem)
The DVB-RCCL/DAVIC specification was developed by a combination of standards bodies including DAVIC, IEEE 802.14, and the ATM Forum. The specification has been recognized as the preferred technology by the ECCA, a consortium of European MSOs. As a result, it represents the only technology that rivals DOCSIS as a standard for international deployments.
Vendor support for the specification has been outstanding considering the emergence of DOCSIS as an ITU endorsed standard. To date, the following vendors have declared an intention to build to the spec: Alcatel, Cisco, DiviCom, Hughes Network Systems, Nokia Multimedia Network Terminals, Sagem, The
Industree, Thomson Broadcast Systems (a subsidiary of Thomson Multimedia), and Thomson Multimedia.
The leading cable modem suppliers have not committed to the specification. They are holding out under the belief that a Euro-modified version of DOCSIS will prevail in Europe. The jury is still out on this market. While many of the European MSOs have committed to DVB-RCCL/DAVIC, other big providers have already chosen to deploy DOCSIS technology. Many providers are expected to stick with proprietary gear.
Select DVB-RCCL/DAVIC specs:
(the following has been provided courtesy of Cisco)
A cable modem is in DAVIC terminology called a "Set-top box" (STB).
DAVIC specifies the following types of cable modems:
stand-alone modem with Ethernet if (IEEE 802.3)
stand-alone modem with FireWire if (IEEE 1394)
internal PC adapter
DAVIC specifies the following tools to be used for cable modems:
Passband bi-directional PHY on coax
Passband unidirectional PHY on coax
The "Passband unidirectional PHY on coax" tool DAVIC 1.3 part 7,
section 7, specifies the downstream physical layer and framing
(QAM-modulation, MPEG-frames and
ATM-frames). Downstream bit rates are upto 56 Mbps, which can be
achieved when using 8 MHz carriers and 256QAM modulation. The usage of a
QAM carrier for
downstream is called In-band signaling (IB).
The "Passband bi-directional PHY on coax" tool, DAVIC 1.3 part 7,
section 8, specifies the upstream and downstream physical layer, framing
and MAC-layer protocols, The
upstream physical layer protocol describes QPSK modulation with ATM
cells. Upstream bit-rate is up-to 3 Mbps. Downstream physical layer is also
QPSK with bit-rates of
upto 3 Mbps. The usage of QPSK modulation for downstream is called
Out-of-band (OOB) signaling.
The higher level protocols specifies ATM framing (UNI-format ITU-T
I.361) using LLC/SNAP (RFC 1483) and AAL5 (ITU-T I.363.5) to encapsulate IP
(RFC 791) packets.
ATM signaling can be done with either UNI (ITU-T Q.2931) or by
proxy using DSM-CC (Digital Storage Media Configuration and Control,
ISO/IEC 13818-6).
For network management SNMP is specified.
DVB (Digital Video Broadcasting) has with minor modifications
defined the lower layers for CATV networks:
DVB-RCC is identical to DAVIC "Passband bi-directional PHY on
coax" with minor modifications. DVB-RCC is available as
ETSI standard ETS 300 800, title: "Digital Video Broadcasting
(DVB); Interaction channel for Cable TV distribution systems
(CATV)"
DVB-C is identical to DAVIC "Passband unidirectional PHY on
coax" with minor modifications. DVB-C is available as ETSI
standard ETS 300 429, title: "Digital Video Broadcasting (DVB);
Framing structure, channel coding and modulation
for cable systems"
DVB/DAVIC Consortium
ECCA
EuroCableLabs
DVB DAVIC SPECS
IPCDN (IP over Cable Data Network)
The IPCDN is working on definitions of how IP will be supported by cable networks. The effort is ongoing.
Mailing List : ipcdn-request@terayon.com
The ATM Forum Residential Broadband Working Group
The ATM Forum is resolving the VPI and VCI multiplexing and concentration,
traffic management support, UNI signaling termination, service model
definition, voice
telephony over ATM support and interface to 802.14.
PacketCable
PacketCable is an effort led by a consortium of MSOs and CableLabs to develop a specification for supporting fax and voice over IP over a cable network.