Editing Cable modem (section)

==History==
===MITRE Cablenet===
[[Internet Experiment Note|Internet Experiment Note (IEN)]] 96<ref name="IEN 96">[http://ftp.rfc-editor.org/in-notes/ien/ien96.txt IEN 96] - The [[MITRE]] Cablenet Project</ref> (1979) describes an early [[RF]] cable modem system. From pages 2 and 3 of IEN 96:
<blockquote>The Cable-Bus System

The MITRE/Washington Cablenet system is based on a technology developed at MITRE/Bedford. Similar cable-bus systems are in operation at a number of government sites, e.g. [[Walter Reed Army Hospital]], and the [[NASA]] [[Johnson Space Center]], but these are all standalone, local-only networks.

The system uses standard [[community antenna television]] (CATV) [[coaxial cable]] and microprocessor based Bus Interface Units (BIUs) to connect subscriber [[computer]]s and [[Terminal (telecommunication)|terminals]] to the cable. ... The cable bus consists of [[Four-wire circuit|two parallel]] coaxial cables, one inbound and the other outbound. The inbound cable and outbound cable are connected at one end, the [[Cable television headend|headend]], and [[Electrical termination|electrically terminated]] at their other ends. This architecture takes advantage of the well developed [[Simplex communication|unidirectional]] CATV [[Distribution amplifier|components]].<ref name="RF Micro Devices, Inc. Whitepaper Describing Historical CATV Components">{{cite web|url=http://www.piedmontscte.org/resources/CATV+Hybrid+Amplifier+Modules+Past$2C+Present$2C+FutureWP.pdf|title=RF Micro Devices, Inc. Whitepaper Describing Historical CATV Components|website=Piedmontscte.org|access-date=2016-08-03|quotation=Amplifiers are one of the common components used in CATV system}}</ref> The [[Network topology|topology]] is dendritic (i.e. [[Tree topology|branched like a tree]]).<br/>
...<br/>
The BIUs contain [[Radio Frequency]] (RF) modems which [[Modulation|modulate]] a [[carrier signal]] to transmit [[Digital signal (electronics)|digital]] [[Information theory|information]] using 1 [[MHz]] of the available [[Bandwidth (signal processing)|bandwidth]] in the 24&nbsp;MHz frequency range. The remainder of the 294&nbsp;MHz bandwidth can be used to carry other [[communication channel]]s, such as [[Terrestrial television|off-the-air]] [[NTSC|TV]], [[FM radio|FM]], [[Closed-circuit television|closed circuit TV]], or a [[Voice frequency|voice]] [[Digital Telephony|telephone system]], or, other digital channels. The [[Bit rate|data rate]] of our test-bed system is 307.2&nbsp;[[Kilobit per second|kbps]].</blockquote>

===IEEE 802.3b (10BROAD36)===
The [[IEEE]] [[IEEE 802|802 Committee]] defined [[10BROAD36]] in [[10BROAD36|802.3b-1985]]<ref name="IEEE 802.3b (10BROAD36) Standard">[http://standards.ieee.org/findstds/standard/802.3b-1985.html IEEE 802.3b-1985 (10BROAD36)] {{Webarchive|url=https://web.archive.org/web/20120225203804/http://standards.ieee.org/findstds/standard/802.3b-1985.html |date=2012-02-25 }} - Supplement to 802.3: Broadband Medium Attachment Unit and Broadband Medium Specifications, Type 10BROAD36 (Section 11)</ref> as a {{val|10|ul=Mbit/s}} [[IEEE 802.3]]/[[Ethernet]] broadband system to run up to {{convert|3600|m}} over CATV coax network cabling. The word ''[[broadband]]'' as used in the original IEEE 802.3 specifications implied operation in [[Multiplexing#Frequency-division multiplexing|frequency-division multiplexed]] ([[Frequency-division multiplexing|FDM]]) channel bands as opposed to digital ''[[baseband]]'' [[Square wave (waveform)|square-waveform]] [[modulation]]s (also known as [[line coding]]), which begin near zero [[Hz]] and [[Fourier series|theoretically]] consume [[Square wave (waveform)#Fourier Analysis|infinite]] [[frequency bandwidth]]. (In real-world systems, higher-order [[signal]] [[Square wave (waveform)#Fourier Analysis|components]] become indistinguishable from background [[Signal-to-noise ratio|noise]].) In the market [[10BROAD36]] equipment was not developed by many vendors nor deployed in many user networks as compared to equipment for IEEE 802.3/[[Ethernet]] [[Baseband#Baseband Ethernet|baseband]] standards such as [[10BASE5]] (1983), [[10BASE2]] (1985), [[10BASE-T]] (1990), etc.

===IEEE 802.7===
The [[IEEE]] 802 Committee also specified a broadband CATV digital networking standard in 1989 with [[IEEE 802.7|802.7-1989]].<ref name="IEEE 802.7-1989 Standard">{{cite web|url=http://standards.ieee.org/findstds/standard/802.7-1989.html |archive-url=https://archive.today/20130415013437/http://standards.ieee.org/findstds/standard/802.7-1989.html |url-status=dead |archive-date=April 15, 2013 |title=IEEE SA - 802.7-1989 - Local Area Networks: IEEE Recommended Practice: Broadband Local Area Networks |website=[[IEEE]] |date=1990-03-09 |access-date=2016-08-03}}</ref> However, like [[10BROAD36]], 802.7-1989 saw little commercial success.

===Hybrid networks===
Hybrid Networks developed, demonstrated and patented the first high-speed, asymmetrical cable modem system in 1990. A key Hybrid Networks insight was that in the nascent days of the Internet, data downloading constitutes the majority of the data traffic, and this can be served adequately with a highly asymmetrical data network (i.e. a large downstream data pipe and many small upstream data pipes). This allowed CATV operators to offer high-speed data services immediately without first requiring an expensive system upgrade. Also key was that it saw that the upstream and downstream communications could be on the same or different communications media using different protocols working in each direction to establish a closed-loop communications system. The speeds and protocols used in each direction would be very different. The earliest systems used the [[public switched telephone network]] (PSTN) for the return path since very few cable systems were bi-directional. Later systems used CATV for the upstream as well as the downstream path. Hybrid's system architecture is used for most cable modem systems today.

===LANcity===
LANcity was an early pioneer in cable modems, developing a proprietary system that was widely deployed in the U.S. LANcity, which was led by the Iranian-American engineer [[Rouzbeh Yassini]], was then acquired by [[Bay Networks]].<ref>{{Cite web|url=https://www.cnet.com/news/bay-networks-to-acquire-lancity/|title=Bay Networks to acquire LANcity|last=staff|first=CNET News|website=CNET|language=en|access-date=2019-09-05}}</ref> Bay Networks was subsequently acquired by [[Nortel]].<ref>{{Cite web|url=https://www.sfgate.com/business/article/Telecom-Giants-To-Merge-Bay-Networks-bought-by-3003305.php|title=Telecom Giants To Merge / Bay Networks bought by Nortel for $7.2 billion|last1=Marshall|first1=Jonathan|last2=Writer|first2=Chronicle Staff|date=1998-06-16|website=SFGate|access-date=2019-09-05}}</ref> Nortel at the time had formed a joint-venture with [[Antec]] called [[ARRIS]] Interactive.<ref>{{Cite web|url=https://www.cnet.com/news/nortel-ups-stake-in-joint-venture-with-antec/|title=Nortel ups stake in joint venture with Antec|website=CNET|language=en|access-date=2019-09-05}}</ref> Because of contractual agreements with Antec involving this joint venture, Nortel spun the LANCity group out into the ARRIS Interactive joint-venture. ARRIS continues to make cable modems and [[cable modem termination system]] (CMTS) equipment compliant with the [[DOCSIS]] standard.

===Zenith homeworks===
[[Zenith Electronics|Zenith]] offered a cable modem technology using its own protocol which it introduced in 1993, being one of the first cable modem providers. The [[Zenith Cable Modem]] technology was used by several cable television systems in the United States and other countries, including Cox Communications San Diego, Knology in the Southeast United States, [[Ameritech]]'s Americast service (later to be sold off to [[Wide Open West]] after the SBC / Ameritech merger), Cogeco in Hamilton Ontario and Cablevision du Nord de Québec in Val-d'Or.<ref>{{cite news|title=Americast Places $1-Billion Order for Set-Top Boxes |newspaper=[[Los Angeles Times]]|author=Sallie Hofmeister|url=https://www.latimes.com/archives/la-xpm-1996-08-23-fi-36983-story.html|access-date=2010-08-28 | date=1996-08-23}}</ref> Zenith Homeworks used BPSK (Bi-Phase Shift Keyed) modulation to achieve 500&nbsp;Kbit/sec in 600&nbsp;kHz, or {{nowrap|4 Mbit/s}}ec in 6&nbsp;MHz.<ref>{{cite book|title=Network Design: Principles and Applications|author=Gilbert Held|year=2000|page=765|publisher=Auerbach Publications|url=https://books.google.com/books?id=06uBL8vGpoIC&q=zenith+cable+modem&pg=PA765|isbn=978-0-8493-0859-8}}</ref>

===Com21===
{{main|Com21}}
[[Com21]] was another early pioneer in cable modems, and quite successful until proprietary systems were made obsolete by the DOCSIS standardization. The Com21 system used a ''ComController'' as the central bridge in CATV network head-ends, the ComPort cable modem in various models and the NMAPS management system using [[HP OpenView]] as the platform. Later they also introduced a return path multiplexer to overcome noise problems when combining return path signals from multiple areas. The proprietary protocol was based on [[Asynchronous Transfer Mode]] (ATM). The central ComController switch was a modular system offering one downstream channel (transmitter) and one management module. The remaining slots could be used for upstream receivers (2 per card), dual Ethernet 10BaseT and later also [[Fast Ethernet]] and ATM interfaces. The ATM interface became the most popular, as it supported the increasing bandwidth demands and also supported [[VLAN]]s.
Com21 developed a DOCSIS modem, but the company filed for bankruptcy in 2003 and closed. The DOCSIS CMTS assets of COM21 were acquired by [[ARRIS]].

===CDLP===
CDLP was a proprietary system manufactured by [[Motorola]]. CDLP [[customer premises equipment]] (CPE) was capable of both [[PSTN|PSTN (telephone network)]] and radio frequency (cable) return paths. The PSTN-based service was considered 'one-way cable' and had many of the same drawbacks as [[satellite Internet]] service; as a result, it quickly gave way to "two-way cable." Cable modems that used the RF cable network for the return path were considered 'two-way cable', and were better able to compete with the bi-directional [[digital subscriber line]] (DSL) service. The standard is in little use now as new providers use, and existing providers having changed to, the DOCSIS standard. The Motorola CDLP proprietary CyberSURFR is an example of a device that was built to the CDLP standard, capable of a peak {{nowrap|10 Mbit/s}} downstream and {{nowrap|1.532 Mbit/s}} upstream. CDLP supported a maximum downstream bandwidth of {{nowrap|30 Mbit/s}} which could be reached by using several cable modems.

The [[Australia]]n ISP [[BigPond]] employed this system when it started cable modem tests in 1996. For a number of years [[cable Internet access]] was only available in [[Sydney]], [[Melbourne]] and [[Brisbane]] via CDLP. This network ran parallel to the newer DOCSIS system for several years. In 2004, the CDLP network was terminated and replaced by DOCSIS.

CDLP has also been rolled out at the French cable operator [[Numericable]] before upgrading its IP broadband network using DOCSIS.

===DVB/DAVIC===
[[Digital Video Broadcasting]] ([[DVB]]) and Digital Audio Visual Council (DAVIC) are European-formed organizations that developed some cable modem standards. However, these standards have not been as widely adopted as DOCSIS.

===IEEE 802.14===
In the mid-1990s the [[IEEE 802]] committee formed a subcommittee (802.14)<ref name="IEEE 802.14 WG Homepage">{{cite web|url=http://walkingdog.com/ |title=WalkingDog.com |access-date=2012-05-13 |url-status=bot: unknown |archive-url=https://web.archive.org/web/19961226193928/http://walkingdog.com/ |archive-date=1996-12-26 }} The IEEE 802.14 Working Group used WalkingDog.com as its web site.</ref> to develop a standard for cable modem systems. IEEE 802.14 developed a draft standard, which was [[Asynchronous Transfer Mode|ATM-based]]. However, the [[IEEE 802.14|802.14]] working group was disbanded when North American [[multiple system operator|multi system operators]] ([[multiple system operator|MSOs]]) instead backed the then-fledgling [[DOCSIS|DOCSIS 1.0]] specification, which generally used [[best-effort service]] and was [[Internet Protocol|IP-based]] (with extension [[Code point|codepoints]] to support [[Asynchronous Transfer Mode|ATM]]<ref name="DOCSIS RFI 1.0-I01">[http://www.cablelabs.com/specifications/SP-RFI-I01-970326.pdf DOCSIS RFI 1.0-I01 (March 26, 1997)] {{webarchive|url=https://web.archive.org/web/20110525094347/http://www.cablelabs.com/specifications/SP-RFI-I01-970326.pdf |date=May 25, 2011 }} (See section 6.2.3 for the DOCSIS [[Asynchronous Transfer Mode|ATM]] codepoint. See sections 6.1.2.3, 6.2.5.3, 6.4.7, 9, and 9.2.2 for DOCSIS 1.0 QoS mechanisms.)</ref> for [[Quality of service|QoS]] in the future). [[multiple system operator|MSOs]] were interested in quickly deploying service to compete for [[Internet access|broadband Internet access]] customers instead of waiting on the slower, iterative, and deliberative processes of standards development committees. Albert A. Azzam was Secretary of the IEEE 802.14 Working Group,<ref name="IEEE 802.14 WG Officers">{{cite web|url=http://www.walkingdog.com/catv/officers.htm |title=IEEE 802.14 WG Officers |access-date=2012-05-13 |url-status=bot: unknown |archive-url=https://web.archive.org/web/19970129161548/http://www.walkingdog.com/catv/officers.htm |archive-date=1997-01-29 }}</ref> and his book, ''High-Speed Cable Modems'',<ref name="Azzam - High Speed Cable Modems">{{cite book |last1=Azzam |first1=Albert A. |title=High speed cable modems : including IEEE 802.14 standards |date=1997 |publisher=New York : McGraw-Hill |location=New York, NY |isbn=978-0-07-006417-1 |url=https://archive.org/details/highspeedcablemo0000azza |access-date=7 April 2024}}</ref> describes many of the proposals submitted to 802.14.

===IETF===
Although the [[Internet Engineering Task Force]] (IETF) generally does not generate complete cable modem standards, the IETF chartered [[Working Groups]] ([[Working group|WGs]]) that produced various standards related to cable modem technologies (including 802.14, DOCSIS, [[PacketCable]], and others). In particular, the IETF WGs on IP over Cable Data Network (IPCDN)<ref name="IETF IPCDN WG">{{cite web|url=http://tools.ietf.org/wg/ipcdn/ |title=Ipcdn Status Pages |website=Tools.ietf.org |access-date=2016-08-03}}</ref> and IP over [[Digital Video Broadcasting]] (DVB)<ref name="IETF IPDVB WG">{{cite web|url=http://tools.ietf.org/wg/ipdvb/ |title=Ipdvb Status Pages |website=Tools.ietf.org |access-date=2016-08-03}}</ref> produced some standards applicable to cable modem systems, primarily in the areas of [[Simple Network Management Protocol]] (SNMP) [[Management information base|Management Information Bases]] ([[Management information base|MIBs]]) for cable modems and other networking equipment that operates over CATV [[Television network|networks]].

===DOCSIS===
{{main|DOCSIS}}
In the late 1990s, a consortium of US [[Multiple system operator|cable operators]], known as "MCNS" formed to quickly develop an open and interoperable cable modem specification. The group essentially combined technologies from the two dominant proprietary systems at the time, taking the [[physical layer]] from the [[Motorola]] [[#CDLP|CDLP]] system and the [[MAC layer]] from the LANcity system. When the initial specification had been drafted, the MCNS consortium handed over control of it to [[CableLabs]] which maintained the specification, promoted it in various standards organizations (notably [[SCTE]] and [[ITU]]), developed a certification testing program for cable modem equipment, and has since drafted multiple extensions to the original specification.

While deployed [[DOCSIS|DOCSIS RFI 1.0]] equipment generally only supported [[best-effort service]], the DOCSIS RFI 1.0 Interim-01 document discussed [[quality of service]] (QoS) extensions and mechanisms using [[IntServ]], [[Resource Reservation Protocol|RSVP]], [[Real-time Transport Protocol|RTP]], and Synchronous Transfer Mode (STM) [[telephony]] (as opposed to [[Asynchronous Transfer Mode|ATM]]).<ref name="DOCSIS RFI 1.0-I01"/> [[DOCSIS|DOCSIS RFI 1.1]]<ref name="DOCSIS RFI 1.1-I01">[https://web.archive.org/web/20200729172439/https://www.cablelabs.com/specifications/SP-RFIv1.1-I01-990311.pdf DOCSIS RFI 1.1-I01 (March 11, 1999)] (See section 8 and Appendix M.)</ref> later added more robust and standardized QoS mechanisms to DOCSIS. [[DOCSIS|DOCSIS 2.0]] added support for [[Synchronous Code Division Multiple Access|S-CDMA]] [[PHY]], while DOCSIS 3.0 added [[IPv6]] support and [[channel bonding]] to allow a single cable modem to use concurrently more than one upstream channel and more than one downstream channel in parallel.

Virtually all cable modems operating in the field today are compliant with one of the DOCSIS versions. Because of the differences in the European [[PAL]] and US's [[NTSC]] systems two main versions of DOCSIS exist, DOCSIS and EuroDOCSIS. The main differences are found in the width of RF-channels: 6&nbsp;MHz for the US and 8&nbsp;MHz for Europe. A third variant of DOCSIS was developed in [[Japan]] and has seen limited deployment in that country.

Although interoperability "was the whole point of the DOCSIS project,"<ref>{{cite web|url=http://stuff.mit.edu/afs/sipb.mit.edu/contrib/doc/DOCSIS/overview/certification/Certification_Overview.pdf |title=DOCSIS Modem Interoperability and Certification Overview |website=Stuff.mit.edu |access-date=2016-08-03}}</ref> most cable operators only approve a very restricted list of cable modems on their network,<ref>{{cite web |url=http://teksavvy.com/en/residential/internet/cable |title=Cable |website=TekSavvy.com |access-date=2016-08-03 |archive-url=https://web.archive.org/web/20160801135543/http://teksavvy.com/en/residential/internet/cable |archive-date=2016-08-01 |url-status=dead }}</ref><ref>{{cite web|url=http://www.vmedia.ca/en/internet/compatible-modems |title=Compatible Modems |website=vmedia.ca |access-date=2021-10-27}}</ref><ref>{{cite web |url=http://www.acanac.ca/Approved_Modems_Ontario.html |title=Unlimited Internet Plans Quebec &#124; Cable, Fibre Optic &#124; Acanac |website=Acanac.ca |access-date=2016-08-03 |archive-url=https://web.archive.org/web/20150512090341/http://www.acanac.ca/Approved_Modems_Ontario.html |archive-date=2015-05-12 |url-status=dead }}</ref><ref>{{Cite web|url=http://www.worldline.ca/services/high-speed-internet/cable/75/|title=Fast Unlimited Download High Speed Cable 75 Internet Plus Home Phone Bundle|website=www.worldline.ca|language=en|access-date=2018-04-23}}</ref> identifying the 'allowed' modems by their brand, models, sometimes firmware version and occasionally going as far as imposing a hardware version of the modem, instead of simply allowing a supported DOCSIS version.

=== Multimedia over Coax Alliance ===
{{main|Multimedia over Coax Alliance}}In 2004, the Multimedia over Coax Alliance (MoCA) was established to develop industry standards for the connected home using the existing coaxial cabling. Initially developed for in-home networking with MoCA 1.0/1.1, the MoCA standards have continued to develop with MoCA 2.0/2.1 in 2010 and MoCa 2.5 in 2016.

In 2017, Multimedia over Coax Alliance introduced MoCA Access specification, based on the MoCA 2.5 standard, suitable for addressing broadband network access in-building using coaxial cabling.<ref>{{Cite web|url=http://www.mocalliance.org/access/index.htm|title=MoCA Access™|last=KMCreative|website=www.mocalliance.org|language=en|access-date=2017-10-03}}</ref> MoCA Access extends MoCA 2.5 in-home networking to fit operators and ISPs that are installing fiber-to-the-basement/drop point (FTTB/FTTdp) and want to use the existing coax for connection to each apartment or house."