Editing Internet access (section)

===Hardwired broadband access<span class="anchor" id="Hardwired broadband"></span>===

The term ''[[broadband]]'' includes a broad range of technologies, all of which provide higher data rate access to the Internet. The following technologies use wires or cables in contrast to wireless broadband described later.

====Integrated Services Digital Network====
[[Integrated Services Digital Network]] (ISDN) is a switched telephone service capable of transporting voice and digital data, and is one of the oldest Internet access methods. ISDN has been used for voice, video conferencing, and broadband data applications. ISDN was very popular in Europe, but less common in North America. Its use peaked in the late 1990s before the availability of DSL and cable modem technologies.<ref>{{cite book |author=William Stallings |title=ISDN and Broadband ISDN with Frame Relay and ATM |edition=4th |publisher=Prentice Hall |year=1999 |page=542 |isbn=978-0139737442 |url=http://www.pearsonhighered.com/educator/product/ISDN-and-Broadband-ISDN-with-Frame-Relay-and-ATM-4E/9780139737442.page |url-status=live |archive-url=https://web.archive.org/web/20150924071103/http://www.pearsonhighered.com/educator/product/ISDN-and-Broadband-ISDN-with-Frame-Relay-and-ATM-4E/9780139737442.page |archive-date=2015-09-24 }}</ref>

Basic rate ISDN, known as ISDN-BRI, has two 64&nbsp;kbit/s "bearer" or "B" channels. These channels can be used separately for voice or data calls or bonded together to provide a 128&nbsp;kbit/s service. Multiple ISDN-BRI lines can be bonded together to provide data rates above 128&nbsp;kbit/s. Primary rate ISDN, known as ISDN-PRI, has 23 bearer channels (64&nbsp;kbit/s each) for a combined data rate of 1.5&nbsp;Mbit/s (US standard). An ISDN E1 (European standard) line has 30 bearer channels and a combined data rate of 1.9&nbsp;Mbit/s. ISDN has been replaced by DSL technology,<ref>{{cite web | url=https://www.ciscopress.com/articles/article.asp?p=2832405&seqNum=5 | title=Selecting a WAN Technology (1.2) > WAN Concepts &#124; Cisco Press }}</ref> and it required special telephone switches at the service provider.<ref>{{cite web | url=https://books.google.com/books?id=pxcEAAAAMBAJ&dq=isdn+adsl&pg=PA68 | title=Network World | date=23–30 December 1996 }}</ref>

====Leased lines====
[[Leased line]]s are dedicated lines used primarily by ISPs, business, and other large enterprises to connect LANs and campus networks to the Internet using the existing infrastructure of the [[Public switched telephone network|public telephone network]] or other providers. Delivered using wire, [[optical fiber]], and [[radio]], leased lines are used to provide Internet access directly as well as the building blocks from which several other forms of Internet access are created.<ref name="Horak">[http://www.wiley.com/WileyCDA/WileyTitle/productCd-0470396075.html ''Telecommunications and Data Communications Handbook''] {{webarchive|url=https://web.archive.org/web/20130308075758/http://www.wiley.com/WileyCDA/WileyTitle/productCd-0470396075.html |date=2013-03-08 }}, Ray Horak, 2nd edition, Wiley-Interscience, 2008, 791 p., {{ISBN|0-470-39607-5}}</ref>

[[T-carrier]] technology<ref name="lightwaveonline.com">{{cite web | url=https://www.lightwaveonline.com/fttx/pon-systems/article/16649783/fiber-optics-among-carrier-ethernets-multiple-access-technologies | title=Fiber optics among Carrier Ethernet's multiple access technologies | date=July 2009 }}</ref> dates to 1957 and provides data rates that range from 56 and {{val|64|u=kbit/s}} ([[Digital Signal 0|DS0]]) to {{val|1.5|u=Mbit/s}} ([[Digital Signal 1|DS1]] or T1), to {{val|45|u=Mbit/s}} ([[Digital Signal 3|DS3]] or T3).<ref name="auto">{{cite journal | url=https://ieeexplore.ieee.org/document/774937 | doi=10.1109/6294.774937 | title=Emerging high-speed access technologies | year=1999 | last1=Cuffie | first1=D. | last2=Biesecker | first2=K. | last3=Kain | first3=C. | last4=Charleston | first4=G. | last5=Ma | first5=J. | journal=IT Professional | volume=1 | issue=2 | pages=20–28 | url-access=subscription }}</ref> A T1 line carries 24 voice or data channels (24 DS0s), so customers may use some channels for data and others for voice traffic or use all 24 channels for clear channel data. A DS3 (T3) line carries 28 DS1 (T1) channels. Fractional T1 lines are also available in multiples of a DS0 to provide data rates between 56 and {{val|1,500|u=kbit/s}}. T-carrier lines require special termination equipment such as [[Data service unit]]s<ref>{{cite book | url=https://books.google.com/books?id=VZ0vDwAAQBAJ&dq=data+service+unit+t1&pg=PA375 | title=Transmission Systems Design Handbook for Wireless Networks | isbn=978-1-58053-243-3 | last1=Lehpamer | first1=Harvey | date=2002 | publisher=Artech House }}</ref><ref>{{cite book | url=https://books.google.com/books?id=SQ2WAAAAQBAJ&dq=data+service+unit+t1&pg=PT89 | title=A Practical Guide to Advanced Networking | isbn=978-0-13-335400-3 | last1=Beasley | first1=Jeffrey S. | last2=Nilkaew | first2=Piyasat | date=5 November 2012 | publisher=Pearson Education }}</ref><ref>{{cite book | url=https://books.google.com/books?id=YSzMBQAAQBAJ&dq=data+service+unit+t1&pg=PA52 | title=Practical Network Design Techniques: A Complete Guide for WANs and LANs | isbn=978-0-203-50745-2 | last1=Held | first1=Gilbert | last2=Ravi Jagannathan | first2=S. | date=11 June 2004 | publisher=CRC Press }}</ref> that may be separate from or integrated into a router or switch and which may be purchased or leased from an ISP.<ref>{{cite book|last=Dean|first=Tamara|title=Network+ Guide to Networks|edition=5th|publisher=Course Technology, Cengage Learning|year=2009|url=http://www.cengage.com/search/productOverview.do?N=0&Ntk=P_Isbn13&Ntt=9781423902454|isbn=978-1-4239-0245-4|url-status=dead|archive-url=https://web.archive.org/web/20130420223256/http://www.cengage.com/search/productOverview.do?N=0&Ntk=P_Isbn13&Ntt=9781423902454|archive-date=2013-04-20}} pp 312–315.</ref> In Japan the equivalent standard is J1/J3. In Europe, a slightly different standard, [[E-carrier]], provides 32 user channels ({{val|64|u=kbit/s}}) on an E1 ({{val|2.0|u=Mbit/s}}) and 512 user channels or 16 E1s on an E3 ({{val|34.4|u=Mbit/s}}).

[[Synchronous Optical Networking]] (SONET, in the U.S. and Canada) and Synchronous Digital Hierarchy (SDH, in the rest of the world)<ref name="lightwaveonline.com"/> are the standard multiplexing protocols used to carry high-data-rate digital bit-streams over optical fiber using [[lasers]] or highly [[coherent light]] from [[light-emitting diodes]] (LEDs). At lower transmission rates data can also be transferred via an electrical interface. The basic unit of framing is an [[OC-3c]] (optical) or [[Synchronous optical networking#The basic unit of transmission|STS-3]]c (electrical) which carries {{val|155.520|u=Mbit/s}}. Thus an OC-3c will carry three [[Optical Carrier#OC-1|OC-1]] (51.84&nbsp;Mbit/s) payloads each of which has enough capacity to include a full DS3. Higher data rates are delivered in OC-3c multiples of four providing [[OC-12]]c ({{val|622.080|u=Mbit/s}}), [[OC-48]]c ({{val|2.488|u=Gbit/s}}), [[OC-192]]c ({{val|9.953|u=Gbit/s}}), and [[OC-768]]c ({{val|39.813|u=Gbit/s}}). The "c" at the end of the OC labels stands for "concatenated" and indicates a single data stream rather than several multiplexed data streams.<ref name="Horak" /> [[Optical transport network]] (OTN) may be used instead of SONET<ref>{{cite book | url=https://books.google.com/books?id=EisDEAAAQBAJ&dq=otn+replaces+sonet&pg=PA613 | title=Springer Handbook of Optical Networks | isbn=978-3-030-16250-4 | last1=Mukherjee | first1=Biswanath | last2=Tomkos | first2=Ioannis | last3=Tornatore | first3=Massimo | last4=Winzer | first4=Peter | last5=Zhao | first5=Yongli | date=15 October 2020 | publisher=Springer }}</ref> for higher data transmission speeds of up to {{val|400|u=Gbit/s}} per OTN channel.

The [[Gigabit Ethernet|1]], [[10 Gigabit Ethernet|10]], [[100 Gigabit Ethernet|40, and 100 Gigabit Ethernet]] [[IEEE 802.3|IEEE standards (802.3)]] allow digital data to be delivered over copper wiring at distances to 100&nbsp;m and over optical fiber at distances to {{val|40|u=km}}.<ref>[http://www.ieee802.org/3/ "IEEE 802.3 Ethernet Working Group"] {{webarchive|url=https://web.archive.org/web/20141012182235/http://www.ieee802.org/3/ |date=2014-10-12 }}, web page, IEEE 802 LAN/MAN Standards Committee, accessed 8 May 2012</ref>

====Cable Internet access====
{{main|Cable Internet access}}
Cable Internet provides access using a [[cable modem]] on [[Hybrid fibre-coaxial|hybrid fiber coaxial]] (HFC) wiring originally developed to carry television signals. Either fiber-optic or coaxial copper cable may connect a node to a customer's location at a connection known as a cable drop. Using a [[cable modem termination system]], all nodes for cable subscribers in a neighborhood connect to a cable company's central office, known as the "head end." The cable company then connects to the Internet using a variety of means – usually fiber optic cable or digital satellite and microwave transmissions.<ref name="Dean322">{{cite book|last=Dean|first=Tamara|title=Network+ Guide to Networks|edition=5th|publisher=Course Technology, Cengage Learning|year=2009|url=http://www.cengage.com/search/productOverview.do?N=0&Ntk=P_Isbn13&Ntt=9781423902454|isbn=978-1-4239-0245-4|url-status=dead|archive-url=https://web.archive.org/web/20130420223256/http://www.cengage.com/search/productOverview.do?N=0&Ntk=P_Isbn13&Ntt=9781423902454|archive-date=2013-04-20}} p 322.</ref> Like DSL, broadband cable provides a continuous connection with an ISP.

[[Downstream (computer science)|Downstream]], the direction toward the user, bit rates can be as much as 1000&nbsp;[[Mbit/s]] in some countries, with the use of [[DOCSIS]] 3.1. Upstream traffic, originating at the user, ranges from 384&nbsp;kbit/s to more than 50&nbsp;Mbit/s. DOCSIS 4.0 promises up to {{val|10|u=Gbit/s}} downstream and {{val|6|u=Gbit/s}} upstream, however this technology is yet to have been implemented in real-world usage. Broadband cable access tends to service fewer business customers because existing television cable networks tend to service residential buildings; commercial buildings do not always include wiring for coaxial cable networks.<ref>{{cite book|last=Dean|first=Tamara|title=Network+ Guide to Networks|edition=5th|publisher=Course Technology, Cengage Learning|year=2009|url=http://www.cengage.com/search/productOverview.do?N=0&Ntk=P_Isbn13&Ntt=9781423902454|isbn=978-1-4239-0245-4|url-status=dead|archive-url=https://web.archive.org/web/20130420223256/http://www.cengage.com/search/productOverview.do?N=0&Ntk=P_Isbn13&Ntt=9781423902454|archive-date=2013-04-20}} p 323.</ref> In addition, because broadband cable subscribers share the same local line, communications may be intercepted by neighboring subscribers. Cable networks regularly provide encryption schemes for data traveling to and from customers, but these schemes may be thwarted.<ref name="Dean322"/>

====Digital subscriber line (DSL, ADSL, SDSL, and VDSL)====
[[Digital subscriber line]] (DSL) service provides a connection to the Internet through the telephone network. Unlike dial-up, DSL can operate using a single phone line without preventing normal use of the telephone line for voice phone calls. DSL uses the high frequencies, while the low (audible) frequencies of the line are left free for [[Plain old telephone service|regular telephone]] communication.<ref name="howstuffworks" /> These frequency bands are subsequently separated by filters installed at the customer's premises.

DSL originally stood for "digital subscriber loop". In telecommunications marketing, the term digital subscriber line is widely understood to mean [[asymmetric digital subscriber line]] (ADSL), the most commonly installed variety of DSL. The data throughput of consumer DSL services typically ranges from 256&nbsp;kbit/s to 20&nbsp;Mbit/s in the direction to the customer (downstream), depending on DSL technology, line conditions, and service-level implementation. In ADSL, the data throughput in the upstream direction, (i.e., in the direction to the service provider) is lower than that in the downstream direction (i.e. to the customer), hence the designation of asymmetric.<ref>[http://whirlpool.net.au/wiki/?tag=ADSL_Theory "ADSL Theory"] {{webarchive|url=https://web.archive.org/web/20100724040222/http://whirlpool.net.au/wiki/?tag=ADSL_Theory |date=2010-07-24 }}, Australian broadband news and information, Whirlpool, accessed 3 May 2012</ref> With a [[symmetric digital subscriber line]] (SDSL), the downstream and upstream data rates are equal.<ref>[http://docwiki.cisco.com/wiki/Digital_Subscriber_Line#SDSL "SDSL"] {{webarchive|url=https://web.archive.org/web/20120418172858/http://docwiki.cisco.com/wiki/Digital_Subscriber_Line |date=2012-04-18 }}, ''Internetworking Technology Handbook'', Cisco DocWiki, 17 December 2009, accessed 3 May 2012</ref>

[[Very-high-bit-rate digital subscriber line]] (VDSL or VHDSL, ITU G.993.1)<ref>{{cite web|url=http://www.kpn.com/artikel.htm?contentid=2895 |publisher=[[KPN]] |title=KPN starts VDSL trials |url-status=dead |archive-url=https://web.archive.org/web/20080504192232/http://www.kpn.com/Artikel.htm?contentid=2895 |archive-date=2008-05-04 }}</ref> is a digital subscriber line (DSL) standard approved in 2001 that provides data rates up to 52&nbsp;Mbit/s downstream and 16&nbsp;Mbit/s upstream over copper wires<ref>{{cite web |url=http://computer.howstuffworks.com/vdsl2.htm |publisher=[[HowStuffWorks]] |title=VDSL Speed |url-status=live |archive-url=https://web.archive.org/web/20100312075145/http://computer.howstuffworks.com/vdsl2.htm |archive-date=2010-03-12 |date=2001-05-21 }}</ref> and up to 85&nbsp;Mbit/s down- and upstream on coaxial cable.<ref>{{cite web |url=http://www.etherwan.com/Product/ViewProduct.asp?View=64 |archive-url=https://web.archive.org/web/20110710203152/http://www.etherwan.com/Product/ViewProduct.asp?View=64 |url-status=dead |archive-date=2011-07-10 |publisher=EtherWAN |title=Industrial VDSL Ethernet Extender Over Coaxial Cable, ED3331 }}</ref> VDSL is capable of supporting applications such as high-definition television, as well as telephone services ([[voice over IP]]) and general Internet access, over a single physical connection.

[[VDSL2]] ([[ITU-T]] [[G.993.2]]) is a second-generation version and an enhancement of VDSL.<ref name="press">{{Cite news |title= New ITU Standard Delivers 10x ADSL Speeds: Vendors applaud landmark agreement on VDSL2 |date= 27 May 2005 |work= News release |publisher= International Telecommunication Union |url= http://www.itu.int/newsroom/press_releases/2005/06.html |access-date= 22 September 2011 |url-status= live |archive-url= https://web.archive.org/web/20160903203113/http://www.itu.int/newsroom/press_releases/2005/06.html |archive-date= 3 September 2016 }}</ref> Approved in February 2006, it is able to provide data rates exceeding 100&nbsp;Mbit/s simultaneously in both the upstream and downstream directions. However, the maximum data rate is achieved at a range of about 300 meters and performance degrades as distance and loop [[attenuation]] increases.

====DSL Rings====
[[DSL Rings]] (DSLR) or Bonded DSL Rings is a ring topology that uses DSL technology over existing copper telephone wires to provide data rates of up to 400&nbsp;Mbit/s.<ref name="financialpost">{{cite news
 |last        = Sturgeon
 |first       = Jamie
 |title       = A smarter route to high-speed Net
 |publisher   = [[National Post]]
 |work        = FP Entrepreneur
 |date        = October 18, 2010
 |url         = http://www.financialpost.com/entrepreneur/smarter+route+high+speed/3687154/story.html
 |access-date  = January 7, 2011
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20101023013214/http://www.financialpost.com/entrepreneur/smarter+route+high+speed/3687154/story.html
 |archive-date = October 23, 2010
 |df          = mdy-all
}}</ref>

====Fiber to the home====
[[Fiber to the x|Fiber-to-the-home]] (FTTH) is one member of the Fiber-to-the-x (FTTx) family that includes Fiber-to-the-building or basement (FTTB), Fiber-to-the-premises (FTTP), Fiber-to-the-desk (FTTD), Fiber-to-the-curb (FTTC), and Fiber-to-the-node (FTTN).<ref name="council">{{cite web |title= FTTH Council – Definition of Terms |date= January 9, 2009 |url= http://ftthcouncil.eu/documents/Reports/FTTH-Definitions-Revision_January_2009.pdf |publisher= FTTH Council |access-date= September 1, 2011 }}{{dead link|date=September 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> These methods all bring data closer to the end user on optical fibers. The differences between the methods have mostly to do with just how close to the end user the delivery on fiber comes. All of these delivery methods are similar in function and architecture to [[hybrid fiber-coaxial]] (HFC) systems used to provide cable Internet access. Fiber internet connections to customers are either AON ([[Active optical network]]) or more commonly PON ([[Passive optical network]]). Examples of fiber optic internet access standards are [[G.984]] (GPON, G-PON) and [[10G-PON]] (XG-PON). ISPs may instead use [[Metro Ethernet]] as a replacement for T1 and Frame Relay lines<ref>{{cite book | url=https://books.google.com/books?id=YKWfuGGSmXMC&dq=metro+ethernet&pg=PA336 | title=Top-down Network Design | isbn=978-1-58705-152-4 | last1=Oppenheimer | first1=Priscilla | date=2004 | publisher=Cisco Press }}</ref> for corporate and institutional customers,<ref>{{cite web | url=https://books.google.com/books?id=T1pBUCDWA5oC&dq=metro+ethernet&pg=PA35 | title=Computerworld | date=20 January 2003 }}</ref> or offer carrier-grade Ethernet.<ref>{{cite book | url=https://books.google.com/books?id=uCCMBgAAQBAJ&dq=metro+ethernet&pg=PA135 | title=Cable Networks, Services, and Management | isbn=978-1-118-83759-7 | last1=Toy | first1=Mehmet | date=2 February 2015 | publisher=John Wiley & Sons }}</ref> Dedicated internet access (DIA) in which the bandwidth is not shared among customers, can be offered over PON fiber optic networks.<ref>https://www.ispreview.co.uk/index.php/2025/05/its-technology-claims-first-live-uk-biz-customer-trial-of-50gbps-pon.html</ref>

The use of [[Fiber-optic communication|optical fiber]] offers much higher data rates over relatively longer distances. Most high-capacity Internet and cable television backbones already use fiber optic technology, with data switched to other technologies (DSL, cable, LTE) for final delivery to customers.<ref>[http://www.fiopt.com/primer.php "FTTx Primer"] {{webarchive|url=https://web.archive.org/web/20081011033903/http://www.fiopt.com/primer.php |date=2008-10-11 }}, Fiopt Communication Services (Calgary), July 2008</ref> Fiber optic is immune to electromagnetic interference.<ref>{{cite book | url=https://books.google.com/books?id=B810SYIAa4IC&dq=fiber+optic+advantages&pg=PA6 | isbn=978-0-07-137842-0 | title=Fiber Optic Installer's Field Manual | date=13 July 2000 | publisher=McGraw Hill Professional }}</ref>

In 2010, Australia began rolling out its [[National Broadband Network]] across the country using fiber-optic cables to 93 percent of Australian homes, schools, and businesses.<ref>[http://www.abc.net.au/news/2010-08-12/big-gig-nbn-to-be-10-times-faster/941408 "Big gig: NBN to be 10 times faster"] {{webarchive|url=https://web.archive.org/web/20120429192147/http://www.abc.net.au/news/2010-08-12/big-gig-nbn-to-be-10-times-faster/941408 |date=2012-04-29 }}, Emma Rodgers, ''ABC News'', Australian Broadcasting Corporation, 12 August 2010</ref> The project was abandoned by the subsequent LNP government, in favor of a hybrid FTTN design, which turned out to be more expensive and introduced delays. Similar efforts are underway in Italy, Canada, India, and many other countries (see Fiber to the premises by country).<ref>[http://www.telecomseurope.net/content/italy-gets-fiber-back-track "Italy gets fiber back on track"] {{webarchive|url=https://web.archive.org/web/20120322205235/http://www.telecomseurope.net/content/italy-gets-fiber-back-track |date=2012-03-22 }}, Michael Carroll, TelecomsEMEA.net, 20 September 2010</ref><ref>[http://www.freevoipcallsolution.com/2010/08/pirelli-broadband-solutions-technology.html "Pirelli Broadband Solutions, the technology partner of fastweb network Ngan"] {{webarchive|url=https://web.archive.org/web/20120328111850/http://www.freevoipcallsolution.com/2010/08/pirelli-broadband-solutions-technology.html |date=2012-03-28 }}, 2 August 2010</ref><ref>[http://www.fiercetelecom.com/story/telecom-italia-rolls-out-100-mbps-ftth-services-catania/2010-11-03 "Telecom Italia rolls out 100 Mbps FTTH services in Catania"] {{webarchive|url=https://web.archive.org/web/20101231123152/http://www.fiercetelecom.com/story/telecom-italia-rolls-out-100-mbps-ftth-services-catania/2010-11-03 |date=2010-12-31 }}, Sean Buckley, FierceTelecom, 3 November 2010</ref><ref>[http://www.sasktel.com/about-us/news/2011-news-releases/sasktel-announces-2011-network-investment-and-fiber-to-the-premises.html "SaskTel Announces 2011 Network Investment and Fiber to the Premises Program"] {{webarchive|url=https://archive.today/20120911184530/http://www.sasktel.com/about-us/news/2011-news-releases/sasktel-announces-2011-network-investment-and-fiber-to-the-premises.html |date=2012-09-11 }}, SaskTel, Saskatchewan Telecommunications Holding Corporation, 5 April 2011</ref>

====Power-line Internet====
[[Power-line Internet]], also known as [[Broadband over power lines]] (BPL), carries Internet data on a conductor that is also used for [[electric power transmission]].<ref name="BERGU14">{{cite book|last1=Berger|first1=Lars T.|last2=Schwager|first2=Andreas|last3=Pagani|first3=Pascal|last4=Schneider|first4=Daniel M.|date=February 2014|title=MIMO Power Line Communications: Narrow and Broadband Standards, EMC, and Advanced Processing|publisher=CRC Press|series=Devices, Circuits, and Systems|isbn=9781466557529|doi=10.1201/b16540-1}}{{Dead link|date=January 2019 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Because of the extensive power line infrastructure already in place, this technology can provide people in rural and low population areas access to the Internet with little cost in terms of new transmission equipment, cables, or wires. Data rates are asymmetric and generally range from 256&nbsp;kbit/s to 2.7&nbsp;Mbit/s.<ref name="HSW-BPL">[http://computer.howstuffworks.com/bpl.htm "How Broadband Over Powerlines Works"] {{webarchive|url=https://web.archive.org/web/20120512090550/http://computer.howstuffworks.com/bpl.htm |date=2012-05-12 }}, Robert Valdes, ''How Stuff Works'', accessed 5 May 2012</ref>

Because these systems use parts of the radio spectrum allocated to other over-the-air communication services, interference between the services is a limiting factor in the introduction of power-line Internet systems. The [[IEEE P1901]] standard specifies that all power-line protocols must detect existing usage and avoid interfering with it.<ref name="HSW-BPL" />

Power-line Internet has developed faster in Europe than in the U.S. due to a historical difference in power system design philosophies. Data signals cannot pass through the step-down transformers used and so a repeater must be installed on each transformer.<ref name="HSW-BPL" /> In the U.S. a transformer serves a small cluster of from one to a few houses. In Europe, it is more common for a somewhat larger transformer to service larger clusters of from 10 to 100 houses. Thus a typical U.S. city requires an order of magnitude more repeaters than a comparable European city.<ref>[http://electrical-engineering-portal.com/north-american-versus-european-distribution-systems "North American versus European distribution systems"] {{webarchive|url=https://web.archive.org/web/20120507211603/http://electrical-engineering-portal.com/north-american-versus-european-distribution-systems |date=2012-05-07 }}, Edvard, Technical articles, Electrical Engineering Portal, 17 November 2011</ref>

====ATM and Frame Relay====
[[Asynchronous Transfer Mode]] (ATM) and [[Frame Relay]] are wide-area networking standards that can be used to provide Internet access directly<ref name="auto"/> or as building blocks of other access technologies. For example, many DSL implementations use an ATM layer over the low-level bitstream layer to enable a number of different technologies over the same link. Customer LANs are typically connected to an ATM switch or a Frame Relay node using leased lines at a wide range of data rates.<ref>[http://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-I.150-199902-I!!PDF-E&type=items ''B-ISDN asynchronous transfer mode functional characteristics''] {{webarchive|url=https://web.archive.org/web/20121012161801/http://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-I.150-199902-I!!PDF-E&type=items |date=2012-10-12 }}, ITU-T Recommendation I.150, February 1999, International Telecommunication Union</ref><ref>[http://searchenterprisewan.techtarget.com/definition/frame-relay "Frame Relay"] {{webarchive|url=https://web.archive.org/web/20120409171824/http://searchenterprisewan.techtarget.com/definition/frame-relay |date=2012-04-09 }}, Margaret Rouse, TechTarget, September 2005</ref>

While still widely used, with the advent of Ethernet over optical fiber, [[MPLS]], [[VPN]]s and broadband services such as cable modem and DSL, ATM and Frame Relay no longer play the prominent role they once did.