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Fiber to the ''x'' (FTTX; also spelled "fibre") or fiber in the loop is a generic term for any
broadband In telecommunications, broadband is wide bandwidth data transmission which transports multiple signals at a wide range of frequencies and Internet traffic types, that enables messages to be sent simultaneously, used in fast internet connections. ...
network architecture using
optical fiber An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means t ...
to provide all or part of the
local loop In telephony, the local loop (also referred to as the local tail, subscriber line, or in the aggregate as the last mile) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the common ...
used for
last mile Last mile may refer to: * Last mile (telecommunications), the final leg of the telecommunications networks that deliver services to retail end-users * Last mile (transportation) Last mile in supply chain management and transportation planning is ...
telecommunications. As fiber optic cables are able to carry much more data than copper cables, especially over long distances, copper telephone networks built in the 20th century are being replaced by fiber. FTTX is a generalization for several configurations of fiber deployment, arranged into two groups: FTTP/FTTH/FTTB (Fiber laid all the way to the premises/home/building) and FTTC/N (fiber laid to the cabinet/node, with copper wires completing the connection). Residential areas already served by balanced pair distribution plant call for a trade-off between cost and capacity. The closer the fiber head, the higher the cost of construction and the higher the channel capacity. In places not served by metallic facilities, little cost is saved by not running fiber to the home. Fiber to the ''x'' is the key method used to drive next-generation access (NGA), which describes a significant upgrade to the broadband available by making a step change in speed and quality of the service. This is typically thought of as asymmetrical with a download speed of 24 Mbit/s plus and a fast upload speed. Ofcom have defined super-fast broadband as "broadband products that provide a maximum download speed that is greater than 24 Mbit/s - this threshold is commonly considered to be the maximum speed that can be supported on current generation (copper-based) networks." A similar network called a
hybrid fiber-coaxial Hybrid fiber-coaxial (HFC) is a telecommunications industry term for a broadband network that combines optical fiber and coaxial cable. It has been commonly employed globally by cable television operators since the early 1990s. In a hybrid fib ...
(HFC) network is used by
cable television Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with broadc ...
operators but is usually not synonymous with "fiber In the loop", although similar advanced services are provided by the HFC networks.
Fixed wireless Fixed wireless is the operation of wireless communication devices or systems used to connect two fixed locations (e.g., building to building or tower to building) with a radio or other wireless link, such as laser bridge. Usually, fixed wireles ...
and mobile wireless technologies such as Wi-Fi,
WiMAX Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options. The WiMA ...
and
3GPP Long Term Evolution In telecommunications, long-term evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/ EDGE and UMTS/ HSPA standards. It improves on those standards' capacity and speed by ...
(LTE) are an alternative for providing
Internet access Internet access is the ability of individuals and organizations to connect to the Internet using computer terminals, computers, and other devices; and to access services such as email and the World Wide Web. Internet access is sold by Internet ...
.


Definitions

The telecommunications industry differentiates between several distinct FTTX configurations. The terms in most widespread use today are: *FTTP (fiber-to-the-premises): This term is used either as a blanket term for both FTTH and FTTB, or where the fiber network includes both homes and small businesses **FTTH (fiber-to-the-home): Fiber reaches the boundary of the living space, such as a box on the outside wall of a home. Passive optical networks and point-to-point Ethernet are architectures that are capable of delivering triple-play services over FTTH networks directly from an operator's central office. Typically providing between 1 and 10 Gbit/s **FTTB (fiber-to-the-building, -business, or -basement): Fiber reaches the boundary of the building, such as the basement in a multi-dwelling unit, with the final connection to the individual living space being made via alternative means, similar to the curb or pole technologies **FTTD can mean two different things: ***(fiber-to-the-desktop or -desk): In an office, fiber connection is installed from the main computer room to a desk or
fiber media converter A fiber media converter is a simple networking device that makes it possible to connect two dissimilar media types such as twisted pair with fiber optic cabling. They were introduced to the industry in the 1990s, and are important in interco ...
near the user's desk ***(fiber-to-the-door): Fiber reaches outside the flat **FTTR can mean two different things: ***(fiber-to-the-radio): Fiber runs to the transceivers of base stations ***(fiber-to-the-router): Fiber connection is installed from the router to the ISP's fiber network **FTTO (fiber-to-the-office): Fiber connection is installed from the main computer room/core switch to a special mini-switch (called FTTO Switch) located at the user's workstation or service points. This mini-switch provides Ethernet services to end user devices via standard
twisted pair Twisted pair cabling is a type of wiring used for communications in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted ba ...
patch cords. The switches are located decentrally all over the building, but managed from one central point **FTTF can mean five different things: ***(fiber-to-the-factory): fiber runs to factory buildings ***(fiber-to-the-farm): fiber runs to agricultural farms ***(fiber-to-the-feeder): a synonym of FTTN ***(fiber-to-the-floor): fiber reaches a junction box at a floor of a building ***(fiber-to-the-frontage): This is very similar to FTTB. In a fiber to the front yard scenario, each fiber node serves a single subscriber. This allows for multi-gigabit speeds using XG-fast technology. The fiber node may be reverse-powered by the subscriber modem **FTTM can mean four different things: ***(fiber-to-the-machine): In a factory, fiber runs to machines ***(fiber-to-the-mast): Fiber runs to wireless masts ***(fiber-to-the-mobile): Fiber runs to base stations ***(fiber-to-the-multi-dwelling-unit): FTTP to apartment buildings **FTTT can mean two different things: ***(fiber-to-the-terminal): In an office, fiber runs to desktop equipment ***(fiber-to-the-tower): Fiber reaches base stations **FTTW (fiber-to-the-wall or -workgroup): In an office, fiber runs to small switches near a group of users *FTTA can mean two different things: **(fiber-to-the-amplifier): Fiber runs to street cabinets **(fiber-to-the-antenna): Fiber runs up antenna towers *FTTCS (fiber-to-the-cell-site): fiber reaches the base station site *FTTE / FTTZ ( fiber-to-the-telecom-enclosure or fiber-to-the-zone): is a form of
structured cabling In telecommunications, structured cabling is building or campus cabling infrastructure that consists of a number of standardized smaller elements (hence structured) called subsystems. Structured cabling components include twisted pair and op ...
typically used in enterprise local area networks, where fiber is used to link the main computer equipment room to an enclosure close to the desk or workstation. FTTE and FTTZ are not considered part of the FTTX group of technologies, despite the similarity in name. *FTTdp (fiber-to-the-distribution-point): This is very similar to FTTC / FTTN but is one-step closer again moving the end of the fiber to within meters of the boundary of the customers premises in last junction possible junction box known as the "distribution point" this allows for near-gigabit speeds *FTTL (fiber-to-the-loop): general term *FTTN / FTTLA (fiber-to-the-node, -neighborhood, or -last-amplifier): Fiber is terminated in a street cabinet, possibly miles away from the customer premises, with the final connections being copper. FTTN is often an interim step toward full FTTH (fiber-to-the-home) and is typically used to deliver 'advanced' triple-play telecommunications services *FTTC / FTTK (fiber-to-the-curb/kerb, -closet, or -cabinet): This is very similar to FTTN, but the street cabinet or pole is closer to the user's premises, typically within , within range for high-bandwidth copper technologies such as wired ethernet or
IEEE 1901 The IEEE Std 1901-2010 is a standard for high speed (up to 500 Mbit/s at the physical layer) communication devices via electric power lines, often called broadband over power lines (BPL). The standard uses transmission frequencies below 100&nbs ...
power line networking and wireless Wi-Fi technology. FTTC is occasionally ambiguously called FTTP (fiber-to-the-pole), leading to confusion with the distinct fiber-to-the-premises system. Typically providing up to 100 Mbit/s *FTTS can mean three different things: ** (fiber-to-the-screen or -seat): On an airplane, fiber reaches the IFE screens ** (fiber-to-the-street): The customer is connected using copper to the fiber passing near the building, up to away. This is a compromise between FTTB and FTTC. Typically providing up to 500 Mbit/s ** (fiber-to-the-subscriber): This is a synonym for FTTP To promote consistency, especially when comparing FTTH penetration rates between countries, the three FTTH Councils of Europe, North America, and Asia-Pacific agreed upon definitions for FTTH and FTTB in 2006, with an update in 2009, 2011 and another in 2015. The FTTH Councils do not have formal definitions for FTTC and FTTN.


Benefits

While fiber optic cables can carry data at high speeds over long distances, copper cables used in traditional telephone lines and
ADSL Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. ...
cannot. For example, the common form of Gigabit Ethernet (1Gbit/s) runs over relatively economical category 5e, category 6 or augmented category 6 unshielded twisted-pair copper cabling but only to . However, 1 Gbit/s Ethernet over fiber can easily reach tens of kilometers. Therefore, FTTP has been selected by every major communications provider in the world to carry data over long 1 Gbit/s symmetrical connections directly to consumer homes. FTTP configurations that bring fiber directly into the building can offer the highest speeds since the remaining segments can use standard Ethernet or coaxial cable. Fiber is often said to be "future-proof" because the data rate of the connection is usually limited by the terminal equipment rather than the fiber, permitting substantial speed improvements by equipment upgrades before the fiber itself must be upgraded. Still, the type and length of employed fibers chosen, e.g. multimode vs. single-mode, are critical for applicability for future connections of over 1 Gbit/s. With the rising popularity of high-definition, on-demand video streaming applications and devices such as YouTube, Netflix, Roku, and Facebook LIVE, the demand for reliable bandwidth is crucial as more and more people begin to utilize these services. FTTC (where fiber transitions to copper in a street cabinet) is generally too far from the users for standard ethernet configurations over existing copper cabling. They generally use
very-high-bit-rate digital subscriber line Very high-speed digital subscriber line (VDSL) and very high-speed digital subscriber line 2 (VDSL2) are digital subscriber line (DSL) technologies providing data transmission faster than the earlier standards of asymmetric digital subscriber line ...
(VDSL) at downstream rates of 80 Mbit/s, but this falls extremely quickly when the distance exceeds 100 meters.


Fiber to the premises

Fiber to the premises (FTTP) is a form of
fiber-optic communication Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is pref ...
delivery, in which an optical fiber is run in an
optical distribution network An access network is a type of telecommunications network which connects subscribers to their immediate service provider. It is contrasted with the core network, which connects local providers to one another. The access network may be fur ...
from the central office all the way to the premises occupied by the subscriber. The term "FTTP" has become ambiguous and may also refer to FTTC where the fiber terminates at a
utility pole A utility pole is a column or post typically made out of wood used to support overhead power lines and various other public utilities, such as electrical cable, optical fiber, fiber optic cable, and related equipment such as Distribution transfor ...
without reaching the premises. Fiber to the premises can be categorized according to where the optical fiber ends: *FTTH (fiber-to-the-home) is a form of fiber-optic communication delivery that reaches one living or working space. The fiber extends from the central office to the subscriber's living or working space. Once at the subscriber's living or working space, the signal may be conveyed throughout the space using any means, including
twisted pair Twisted pair cabling is a type of wiring used for communications in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted ba ...
,
coaxial cable Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulato ...
, wireless, power line communication, or
optical fiber An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means t ...
. *FTTB (fiber-to-the-building or -basement) is a form of fiber-optic communication delivery that necessarily applies only to those properties that contain multiple living or working spaces. The optical fiber terminates before actually reaching the subscribers living or working space itself, but does extend to the property containing that living or working space. The signal is conveyed the final distance using any non-optical means, including twisted pair, coaxial cable, wireless, or power line communication. An
apartment An apartment (American English), or flat (British English, Indian English, South African English), is a self-contained housing unit (a type of residential real estate) that occupies part of a building, generally on a single story. There are man ...
building may provide an example of the distinction between FTTH and FTTB. If a fiber is run to a panel inside each subscriber's apartment unit, it is FTTH. If instead, the fiber goes only as far as the apartment building's shared
electrical room An electrical room is a room or space in a building dedicated to electrical equipment. Its size is usually proportional to the size of the building; large buildings may have a main electrical room and subsidiary electrical rooms. Electrical equip ...
(either only to the
ground floor A storey (British English) or story (American English) is any level part of a building with a floor that could be used by people (for living, work, storage, recreation, etc.). Plurals for the word are ''storeys'' (UK) and ''stories'' (US). Th ...
or to each floor), it is FTTB.


Fiber to the curb/cabinet/node

Fiber to the curb/cabinet (FTTC) is a telecommunications system based on fiber-optic cables run to a platform that serves several customers. Each of these customers has a connection to this platform via
coaxial cable Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulato ...
or
twisted pair Twisted pair cabling is a type of wiring used for communications in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted ba ...
. The "curb" is an abstraction and can just as easily mean a pole-mounted device or communications closet or shed. Typically any system terminating fiber within of the customer premises equipment would be described as FTTC. Fiber to the node or neighborhood (FTTN), sometimes identified with and sometimes distinguished from fiber to the cabinet (FTTC), is a telecommunication architecture based on fiber-optic cables run to a cabinet serving a neighborhood. Customers typically connect to this cabinet using traditional
coaxial cable Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulato ...
or
twisted pair Twisted pair cabling is a type of wiring used for communications in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted ba ...
wiring. The area served by the cabinet is usually less than one mile in radius and can contain several hundred customers. (If the cabinet serves an area of less than in radius, the architecture is typically called FTTC/FTTK.) FTTN allows delivery of broadband services such as high-speed internet. High-speed
communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchron ...
s such as broadband cable access (typically
DOCSIS Data Over Cable Service Interface Specification (DOCSIS) is an international telecommunications standard that permits the addition of high-bandwidth data transfer to an existing cable television (CATV) system. It is used by many cable televisio ...
) or some form of
digital subscriber line Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric d ...
(DSL) are used between the cabinet and the customers. Data rates vary according to the exact protocol used and according to how close the customer is to the cabinet. Unlike FTTP, FTTN often uses existing coaxial or twisted-pair infrastructure to provide
last mile Last mile may refer to: * Last mile (telecommunications), the final leg of the telecommunications networks that deliver services to retail end-users * Last mile (transportation) Last mile in supply chain management and transportation planning is ...
service and is thus less costly to deploy. In the long term, however, its bandwidth potential is limited relative to implementations that bring the fiber still closer to the subscriber. A variant of this technique for
cable television Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with broadc ...
providers is used in a
hybrid fiber-coaxial Hybrid fiber-coaxial (HFC) is a telecommunications industry term for a broadband network that combines optical fiber and coaxial cable. It has been commonly employed globally by cable television operators since the early 1990s. In a hybrid fib ...
(HFC) system. It is sometimes given the acronym FTTLA (fiber-to-the-last-amplifier) when it replaces analog amplifiers up to the last one before the customer (or neighborhood of customers). FTTC allows delivery of broadband services such as high-speed internet. Usually, existing wire is used with
communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchron ...
s such as broadband cable access (typically
DOCSIS Data Over Cable Service Interface Specification (DOCSIS) is an international telecommunications standard that permits the addition of high-bandwidth data transfer to an existing cable television (CATV) system. It is used by many cable televisio ...
) or some form of DSL connecting the curb/cabinet and the customers. In these protocols, the data rates vary according to the exact protocol used and according to how close the customer is to the cabinet. Where it is feasible to run new cable, both fiber and copper ethernet are capable of connecting the "curb" with a full 100Mbit/s or 1Gbit/s connection. Even using relatively cheap outdoor category 5 copper over thousands of feet, all ethernet protocols including power over Ethernet (PoE) are supported. Most fixed wireless technologies rely on PoE, including
Motorola Canopy Cambium Networks is a wireless infrastructure provider that offers fixed wireless and Wi-Fi to broadband service providers and enterprises to provide Internet access. An American telecommunications infrastructure company, it provides wireless tec ...
, which has low-power radios capable of running on a 12VDC power supply fed over several hundred feet of cable. Power line networking deployments also rely on FTTC. Using the
IEEE P1901 The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering Electronics engineering is a sub-discipline of electrical engineering which emerged in the early 20th century a ...
protocol (or its predecessor HomePlug AV) existing electric service cables move up to 1Gbit/s from the curb/pole/cabinet into every AC electrical outlet in the home—coverage equivalent to a robust Wi-Fi implementation, with the added advantage of a single cable for power and data. By avoiding new cable and its cost and liabilities, FTTC costs less to deploy. However, it also has historically had lower bandwidth potential than FTTP. In practice, the relative advantage of fiber depends on the bandwidth available for backhaul,
usage-based billing A data cap, often erroneously referred to as a bandwidth cap, is an artificial restriction imposed on the transfer of data over a network. In particular, it refers to policies imposed by an internet service provider in order to limit customers' u ...
restrictions that prevent full use of last-mile capabilities, and customer premises equipment and maintenance restrictions, and the cost of running fiber that can vary widely with geography and building type. In the United States and Canada, the largest deployment of FTTC was carried out by
BellSouth Telecommunications BellSouth Telecommunications, LLC was an operating company of AT&T that served the southeastern United States. It consisted of the operations of Southern Bell and South Central Bell. BellSouth Telecommunications was a subsidiary of BellSout ...
. With the acquisition of BellSouth by
AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile te ...
, deployment of FTTC will end. Future deployments will be based on either FTTN or FTTP. Existing FTTC plant may be removed and replaced with FTTP. Verizon, meanwhile, announced in March 2010 they were winding down Verizon FiOS expansion, concentrating on completing their network in areas that already had FiOS franchises but were not deploying to new areas, suggesting that FTTH was uneconomic beyond these areas. Verizon also announced (at CES 2010) its entry into the
smart home Smart or SMART may refer to: Arts and entertainment * ''Smart'' (Hey! Say! JUMP album), 2014 * Smart (Hotels.com), former mascot of Hotels.com * ''Smart'' (Sleeper album), 1995 debut album by Sleeper * '' SMart'', a children's television se ...
and power utility data management arenas, indicating it was considering using P1901-based FTTC or some other existing-wire approach to reach into homes, and access additional revenues from the secure
AES-128 The Advanced Encryption Standard (AES), also known by its original name Rijndael (), is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001. AES is a variant ...
bandwidth required for
advanced metering infrastructure A smart meter is an electronic device that records information such as consumption of electric energy, voltage levels, current, and power factor. Smart meters communicate the information to the consumer for greater clarity of consumption beh ...
. However, the largest 1Gbit/s deployment in the United States, in
Chattanooga Chattanooga ( ) is a city in and the county seat of Hamilton County, Tennessee, United States. Located along the Tennessee River bordering Georgia, it also extends into Marion County on its western end. With a population of 181,099 in 2020, ...
, Tennessee, despite being conducted by power utility
EPB EPB of Chattanooga, formerly known as the Electric Power Board of Chattanooga, is an American electric power distribution and telecommunications company owned by the city of Chattanooga, Tennessee. EPB serves nearly 180,000 homes and businesses ...
, was FTTH rather than FTTC, reaching every subscriber in a 600-square-mile area. Monthly pricing of $350 reflected this generally high cost of deployment. However, Chattanooga EPB has reduced the monthly pricing to $70/month. Historically, both telephone and cable companies avoided hybrid networks using several different modes of transport from their point of presence into customer premises. The increased competitive cost pressure, availability of three different existing wire solutions, smart grid deployment requirements (as in Chattanooga), and better hybrid networking tools (with major vendors like
Alcatel-Lucent Alcatel–Lucent S.A. () was a French–American global telecommunications equipment company, headquartered in Boulogne-Billancourt, France. It was formed in 2006 by the merger of France-based Alcatel and U.S.-based Lucent, the latter being a su ...
and Qualcomm Atheros, and Wi-Fi solutions for edge networks, IEEE 1905 and IEEE 802.21 protocol efforts and SNMP improvements) all make FTTC deployments more likely in areas uneconomic to serve with FTTP/FTTH. In effect FTTC serves as a halfway measure between fixed wireless and FTTH, with special advantages for smart appliances and electric vehicles that rely on PLC use already.


Deployments

Operators Operator may refer to: Mathematics * A symbol indicating a mathematical operation * Logical operator or logical connective in mathematical logic * Operator (mathematics), mapping that acts on elements of a space to produce elements of another ...
around the world have been rolling out high-speed Internet access networks since the mid-2000s. Some used a network topology known as Active Ethernet Point-to-Point to deliver services from its central office directly into subscribers' homes. Fiber termination was handled by a residential gateway provided by
Advanced Digital Broadcast Advanced Digital Broadcast (ADB) is a company which provides software, system and services to pay-TV and telecommunication operators, content distributors and property owners around the world. The company specializes also in the development of dig ...
inside a subscriber's home to be shared with other
consumer electronics Consumer electronics or home electronics are electronic ( analog or digital) equipment intended for everyday use, typically in private homes. Consumer electronics include devices used for entertainment, communications and recreation. Usually ...
(CE) devices. Since 2007, Italian access providers Fastweb, Telecom Italia, Vodafone, and Wind participated in an initiative called Fiber for Italy, with the aim of creating a countrywide fiber-to-the-home network in Italy. The pilot taking place in the Italian capital, Rome, has seen symmetrical bandwidth of 100 Mbit/s. Telecom Italia, which refused to take part in the Fiber for Italy initiative, has an even more ambitious plan to bring fiber-to-the-home and fiber-to-the-business to 138 cities by 2018. By the end of December 2010, the total number of fiber-to-the-home enabled homes had passed 2.5 million, with more than 348,000 subscribers.) In September 2010, the European Commission published a new "Recommendation for Regulated Access to NGA Networks" along with a list of measures to promote deployment of fast broadband and next generation access networks. Portugal Telecom plans to complete its fiber-to-the-home nationwide roll out by 2020. Currently 200 mbs down, 100mbs up costs 22 euros per month. Between September 2017 and March 2019, the number of European FTTH and FTTB subscribers increased by nearly 16%. By 2025, the total number of premises passed by FTTH and FTTB infrastructure is expected to reach 187 million throughout Europe. Google Fiber provides speed of up to 1 Gbit/s. Active Line Access is an evolving standard for the provision of services over FTTP networks in the United Kingdom proposed by the regulator Ofcom and developed by the Network Interoperability Consultative Committee.


FTTP


FTTS, FTTH and FTTB

Most FTTH deployments follow one of four primary architecture types: centralized split, distributed split, star architecture, or daisy-chaining. Fiber network developers choose architectures based on a variety of factors, such as the physical geography of the local environment, number of anticipated subscribers, and labor force skill.


FTTN and FTTC

FTTN/C is seen as an interim step towards full FTTH and in many cases triple-play services delivered using this approach to provide up to around 100 Mbit/s have been proven to grow subscriber numbers and ARPU considerably FTTN/C is currently used by a number of operators, including
AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile te ...
in the United States, Germany's
Deutsche Telekom Deutsche Telekom AG (; short form often just Telekom, DTAG or DT; stylised as ·T·) is a German telecommunications company that is headquartered in Bonn and is the largest telecommunications provider in Europe by revenue. Deutsche Telekom was ...
, Greece's OTE, Swisscom, TIM in Italy, Proximus in Belgium, nbn™ in Australia, and Canadian operators Telus,
Cogeco Cogeco Inc. is a Canadian telecommunications and media company. Its corporate offices are located at 1 Place Ville-Marie in Montreal, Quebec. The company is structured into three strategic business units (SBU); Cogeco Connexion, Breezeline ( ...
and
Bell Canada Bell Canada (commonly referred to as Bell) is a Canadian telecommunications company headquartered at 1 Carrefour Alexander-Graham-Bell in the borough of Verdun in Montreal, Quebec, Canada. It is an ILEC (incumbent local exchange carrier) in t ...
.


Optical distribution networks


Direct fiber

The simplest optical distribution network architecture is direct fiber: each fiber leaving the central office goes to exactly one customer. Such networks can provide excellent bandwidth but are more costly due to the fiber and central office machinery. South Africa and specifically in the city of Cape Town have one of the largest direct fiber networks in the world. Cape Town has been on the forefront of telecommunication and connectivity for many years, with a large amount of fiber in the ground and many competitive offerings. Their argument for direct fiber is that multiple operators can patch into the network easily, and troubleshooting made simple. Direct fiber is generally favored by new entrants and competitive operators. A benefit is that no layer 2 networking technologies are excluded, whether passive optical network (PON), active optical network (AON), or other. Any form of regulatory remedy is possible using this topology.


Shared fiber

More commonly, each fiber leaving the central office is actually shared by many customers. It is not until such a fiber gets relatively close to the customers that it is split into individual customer-specific fibers. AONs and PONs both achieve this split.


Active optical network

AONs rely on electrically powered network equipment to distribute the signal, such as a
switch In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of ...
or router. Normally, signals need an optical-electrical-optical transformation in the AON. Each signal leaving the central office is directed only to the customer for whom it is intended. Incoming signals from the customers avoid
colliding In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great fo ...
at the intersection because the powered equipment there provides buffering. Active Ethernet (a type of
ethernet in the first mile Ethernet in the first mile (EFM) refers to using one of the Ethernet family of computer network technologies between a telecommunications company and a customer's premises. From the customer's point of view, it is their first mile, although from th ...
) is a common AON, which uses optical ethernet switches to distribute the signal, incorporating the customers' premises and the central office into a large switched ethernet network. Such networks are identical to ethernet computer networks used in businesses and academic institutions, except that their purpose is to connect homes and buildings to a central office rather than to connect computers and printers within a location. Each switching cabinet can handle up to 1,000 customers, although 400–500 is more typical. This neighborhood equipment performs layer 2 switching or
layer 3 switching A multilayer switch (MLS) is a computer networking device that switches on OSI layer 2 like an ordinary network switch and provides extra functions on higher OSI layers. The MLS was invented by engineers at Digital Equipment Corporation. Switc ...
and routing, offloading full layer 3
routing Routing is the process of selecting a path for traffic in a network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone netw ...
to the carrier's central office. The IEEE 802.3ah standard enables service providers to deliver up to 1000 Mbit/s,
full-duplex A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow ...
, over one single-mode optical fiber FTTP, depending on the provider.


Passive optical network

A passive optical network (PON) is a point-to-multipoint FTTP network architecture in which unpowered optical splitters are used to enable a single optical fiber to serve up to 128 customers. A PON reduces the fiber and central office equipment required compared with point-to-point architecture. The downstream signal coming from the central office is broadcast to each customer premises sharing a fiber. Encryption is used to prevent eavesdropping. Upstream signals are combined using a multiple-access protocol, usually time-division multiple access (TDMA).


Ethernet point-to-point

Point-to-Point Protocol over Ethernet The Point-to-Point Protocol over Ethernet (PPPoE) is a network protocol for encapsulating Point-to-Point Protocol (PPP) frames inside Ethernet frames. It appeared in 1999, in the context of the boom of DSL as the solution for tunneling packet ...
(PPPoE) is a common way of delivering triple- and quad-play (voice, video, data, and mobile) services over both fiber and
hybrid fiber-coaxial Hybrid fiber-coaxial (HFC) is a telecommunications industry term for a broadband network that combines optical fiber and coaxial cable. It has been commonly employed globally by cable television operators since the early 1990s. In a hybrid fib ...
(HFC) networks. Active PPPoE uses dedicated fiber from an operator's central office all the way to the subscribers' homes, while hybrid networks (often FTTN) use it to transport data via fiber to an intermediate point to ensure sufficiently high throughput speeds over last-mile copper connections. This approach has become increasingly popular in recent years with telecoms service providers in both North America (
AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile te ...
, Telus, for example) and Europe's Fastweb, Telecom Italia,
Telekom Austria A1 Telekom Austria Group is a provider of a range of fixed-line, broadband Internet, multimedia services, data, and IT systems, wholesale as well as mobile payment services. It is a subsidiary of Mexican telecommunications conglomerate América M ...
and
Deutsche Telekom Deutsche Telekom AG (; short form often just Telekom, DTAG or DT; stylised as ·T·) is a German telecommunications company that is headquartered in Bonn and is the largest telecommunications provider in Europe by revenue. Deutsche Telekom was ...
, for example. Google has also looked into this approach, amongst others, as a way to deliver multiple services over open-access networks in the United States.Stephen Hardy
"Is Active Ethernet best FTTH option for Google?"
, ''Lightwave'', PennWell Corporation, 24 February 2010


Electrical network

Once on private property, the signal is typically converted into an electrical format. The optical network terminal (ONT, an ITU-T term) or unit (ONU, an identical IEEE term) converts the optical signal into an electrical signal using
thin film A thin film is a layer of material ranging from fractions of a nanometer (monolayer) to several micrometers in thickness. The controlled synthesis of materials as thin films (a process referred to as deposition) is a fundamental step in many a ...
filter technology. These units require electrical power for their operation, so some providers connect them to backup batteries in case of power outages to ensure emergency access to telecommunications. The
optical line termination {{unreferenced, date=April 2016 An optical line termination (OLT), also called an optical line terminal, is a device which serves as the service provider endpoint of a passive optical network. It provides two main functions: # to perform conversio ...
s "range" the optical network terminals or units in order to provide TDMA time slot assignments for upstream communication. For FTTH and for some forms of FTTB, it is common for the building's existing ethernet, phone, and cable TV systems to connect directly to the optical network terminal or unit. If all three systems cannot directly reach the unit, it is possible to combine signals and transport them over a common medium such as Ethernet. Once closer to the end user, equipment such as a router or network interface controller can separate the signals and convert them into the appropriate protocol. For FTTC and FTTN, the combined internet, video and telephone signal travels to the building over existing telephone or cable wiring until it reaches the end-user's living space, where a VDSL or DOCSIS modem converts data and video signals into ethernet protocol, which is sent over the end-user's
category 5 cable Category 5 cable (Cat 5) is a twisted pair cable for computer networks. Since 2001, the variant commonly in use is the Category 5e specification (Cat 5e). The cable standard provides performance of up to 100 MHz and is ...
.


See also

* National broadband plan


References


External links


Fiber to the Home Council: Asia-PacificFibre to the Home Council: EuropeFiber to the Home Council: North AmericaFiber to the Home Council: Latin America Chapter
{{Telecommunications Broadband Network architecture Fiber-optic communications Local loop Telephony Fiber to the premises de:Glasfasernetz de:Fiber In The Loop