- FTTB, FTTC, FTTH, FTTK, FTTN, and FTTP all redirect here. For airports with those ICAO codes, see List of airports in Chad.
Fiber to the x (FTTx) is a generic term for any broadband network architecture using optical fiber to replace all or part of the usual metal local loop used for last mile telecommunications. The generic term was initially a generalization for several configurations of fiber deployment (FTTN, FTTC, FTTB, FTTH...), all starting by FTT but differentiated by the last letter, which is substituted by an x in the generalization.
A schematic illustrating how FTTx architectures vary — with regard to the distance between the
optical fiber and the
end-user. The building on the left is the
central office; the building on the right is one of the buildings served by the central office. Dotted rectangles represent separate living or office spaces within the same building.
The telecommunications industry differentiates between several distinct configurations. The terms in most widespread use today are:
- FTTN - Fiber-to-the-node - fiber is terminated in a street cabinet up to several kilometers away from the customer premises, with the final connection being copper. Fiber-to-the-node is often seen as an interim step towards full FTTH and is currently used by telecoms service providers like AT&T, Deutsche Telekom, Telekom Austria, Belgacom and Swisscom to deliver advanced triple-play services.
- FTTC - Fiber-to-the-curb / Fiber to the cabinet - this is very similar to FTTN, but the street cabinet or pole is closer to the user's premises; typically within 300m, within range for high-bandwidth copper technologies such as wired Ethernet and IEEE P1901 powerline networking, and wireless Wi-Fi technology.
- FTTB - Fiber-to-the-building or Fiber-to-the-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/pole technologies, but also possibly shorter range technology like Thunderbolt.
- FTTH - Fiber-to-the-home - fiber reaches the boundary of the living space, such as a box on the outside wall of a home. It is currently used by Telefonica in the Spain's biggest cities, with speeds of up to 100 Mbit/s (megabits per seconds).
- FTTP - Fiber-to-the premises - this term is used in several contexts: as a blanket term for both FTTH and FTTB, or where the fiber network includes both homes and small businesses.
- FTTD - Fiber-to-the-desk - fiber connection is installed from the main computer room to a terminal or fiber media converter near the user's desk.
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,[1] with an update in 2009.[2] The FTTH Councils do not have formal definitions for FTTC and FTTN.
To some, fiber to the telecom enclosure (FTTE) is not considered to be part of the FTTx group of technologies, despite the similarity in name. FTTE is a form of structured cabling typically used in the enterprise local area network, where fiber is used to link the main computer equipment room to an enclosure close to the desk or workstation.[3] Passive optical networks and Point-to-Point Ethernet are architectures that deliver triple-play services over FTTH networks directly from an operator‘s central office.[4][5]
BT is deploying a FTTC (fiber to the cabinet) system in the UK, as part of its NextGen Access scheme (NGA). Speeds of up to 80 Mbit/s (megabits per second) for downloads to the user, and 20 Mbit/s uploads from the user are possible, according to profile 17a (UK only)
The speeds of fiber optic and copper cables are both limited by length, but copper is much more sharply limited in this respect. For example, the common form of Gigabit Ethernet runs over relatively economical category 5e, category 6, or augmented category 6 unshielded twisted pair copper cabling but only to 100 meters. However, over the right kind of fiber, Gigabit Ethernet can easily reach tens of kilometers.
Even in the commercial world, most computers have copper communication cables. But these cables are short, typically tens of meters. Most metropolitan network links (e.g., those based on telephone or cable television services) are several kilometers long, in the range where fiber significantly outperforms copper. Replacing at least part of these links with fiber shortens the remaining copper segments and allows them to run much faster.
Fiber configurations that bring fiber right into the building can offer the highest speeds since the remaining segments can use standard Ethernet or coaxial cable. Fiber configurations that transition to copper in a street cabinet are generally too far from the users for standard Ethernet configurations over existing copper cabling. They generally use very high bitrate digital subscriber line (VDSL) at downstream rates of several tens of megabits per second.
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 at least some 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 high gigabit connections.
Point-to-Point Protocol over Ethernet is a common way of delivering triple (and quad) play (voice, video, data and mobile) services over both fiber and hybrid fiber coax [HFC] networks. Active Ethernet Point-to-Point 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 a node, to ensure the highest possible 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, Telus, for example) and Europe's Fastweb, Telecom Italia, Telekom Austria and Deutsche Telecom, for example]. Search specialist Google has also looked into this approach, amongst others, as a way to deliver multiple services over open-access networks in the United States.[6]
Fiber to the node (FTTN), also called fiber to the neighborhood or fiber to the cabinet (FTTCab),[7] 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 or twisted pair wiring. The area served by the cabinet is usually less than 1,500 m in radius and can contain several hundred customers. (If the cabinet serves an area of less than 300 m in radius then the architecture is typically called fiber to the curb.)[8]
Fiber to the node allows delivery of broadband services such as high speed Internet. High speed communications protocols such as broadband cable access (typically DOCSIS) or some form of digital subscriber line (DSL) are used between the cabinet and the customers. The data rates vary according to the exact protocol used and according to how close the customer is to the cabinet.
Unlike the competing fiber to the premises technology, fiber to the node often uses the existing coaxial or twisted pair infrastructure to provide last mile service. For this reason, fiber to the node is less costly to deploy. In the long-term, however, its bandwidth potential is limited relative to implementations which bring the fiber still closer to the subscriber.
A variant of this technique for cable television providers is used in a hybrid fiber-coaxial (HFC) system. It is sometimes given the acronym FTTN for Fiber To The Last Amplifier when it replaces analog amplifiers up to the last one before the customer (or neighborhood of customers).
Fiber to the curb (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 or twisted pair. 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 300m of the customer premises equipment would be described as an FTTC deployment.
Fiber to the curb allows delivery of broadband services such as high speed internet. Usually existing wire is used with communications protocols such as broadband cable access (typically DOCSIS) 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 100 megabit or 1000 megabit connection. Even using relatively cheap outdoor category5 copper over several hundred meters, all Ethernet protocols including Power over Ethernet are supported. Most fixed wireless technologies rely on PoE including Motorola Canopy which has low-power radios capable of running on a 12VDC power supply fed over > 100 meters of cable.
Powerline networking deployments also rely on FTTC: Using the IEEE P1901 protocol (or its predecessor HomePlug AV) existing electric service cables move up to a gigabit of data per second 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.
FTTC is subtly distinct from FTTN or FTTP (all are versions of Fiber in the Loop). The main difference is the placement of the cabinet. FTTC will be placed near the "curb" which differs from FTTN which is placed far from the customer and FTTP which is placed right at the serving location.
Unlike the competing fiber to the premises (FTTP) technology, fiber to the curb can use the existing coaxial, twisted pair or AC power line infrastructure to provide last mile service. The G.hn and IEEE P1905 efforts were attempts to unify these existing cables under one management protocol.
By avoiding new cable and its cost and liabilities, fiber to the curb costs less to deploy. However, it also has historically had lower bandwidth potential than fiber to the premises. In practice, the relative advantage of fiber depends on the bandwidth available for backhaul, usage-based billing restrictions that prevent full use of last mile capabilities, and customer premises equipment and maintenance restrictions, and the cost of running fiber which can vary widely with geography and building type.
In the United States of America and Canada, the largest deployment of FTTC was carried out by BellSouth Telecommunications. With the acquisition of BellSouth by AT&T, 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.[9] 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 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 bandwidth required for advanced metering infrastructure. However, the largest gigabit deployment in the US, in Chattanooga, TN, despite being conducted by a power utility [1], was FTTH not FTTC, and reached every single subscriber in a 600 square mile area. Pricing, US$350 for 1000 megabits, reflected this generally high cost of deployment [2]
Historically, both telephone and cable companies avoided hybrid networks using several different transports 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 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 fiber to homes, with special advantages for smart appliances and electric vehicles that rely on PLC use already.
Fiber to the premises is a form of fiber-optic communication delivery in which an optical fiber is run in a distribution network from the central office all the way to the premises occupied by the subscriber. Fiber to the premises is often abbreviated with the acronym FTTP. However, this acronym has become ambiguous and may instead refer to a form of fiber to the curb where the fiber terminates at a utility pole 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.[2] Once at the subscriber's living or working space, the signal may be conveyed throughout the space using any means, including twisted pair, coaxial cable, wireless, power line communication, or optical fiber.
- FTTB (fiber to the building, also called fiber to the basement) is a form of fiber optic communication delivery that necessarily applies only to those properties which 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.[2]
An apartment building may provide an example of the distinction between FTTH and FTTB. If a fiber is run to a panel at each subscriber's apartment, this is FTTH. If instead the fiber goes only as far as the apartment building's shared electrical room, then this is FTTB.
- INDIA - Beam Telecom PVT LTD became the first service provider to deliver triple play serives on FTTH in 2010 in three major township of Hyderabad and making developers and builders understand the benefits of FTTH and partnered with developers to execute FTTH More then 20,000 Homes.
The deployment of an FTTH network meant Fastweb was the first telecom operator to deliver true triple-play services to its subscribers. This contributed to its ARPU [Average Revenue Per User] being amongst the highest in the industry for a number of years during the early 2000s. Its FTTH network also puts it at the forefront of advanced connected home services.
- Fiber for Italy - The Fiber For Italy[11] Initiative has the stated goal of offering 100Mbit/s symmetrical connections to 10 million Italian subscribers across 15 cities by [2018] and up to 1GBps for business customers.[12] It involves operators Wind, Tele2, Vodafone and Fastweb. An ongoing pilot project in the Italian capital Rome delivers symmetrical speeds of up to 100Mbit/s to small businesses. Italian state operator Telecom Italia is not a participant in the Fiber For Italy program, but has independently committed to provide ultra-high speed broadband up to 100Mbit/s symmetrical connections to 50 percent of the country’s population (138 cities) by 2018.[13]
Both Fiber for Italy participants and Telecom Italia are working with Advanced Digital Broadcast to provide residential gateway technology with embedded fiber termination.
Since 2006, Television Sierre SA deploys a FTTH network in most municipalities in the district of Sierre in Switzerland. Triple Play services are offered to the public under the brand Vario.
In October 2011, British operator Hyperoptic launched a 1Gbit/sec FTTH service in London.[14]
In 2011, Mexican operator Telmex launched the FTTH service for its costumers in Mexico City, and in other major cities in Mexico.
FTTN, or Fiber-to-the-node, is currently used by a number of multiple-service operators to deliver advanced triple play services to consumers, including AT&T in the United States for its U-Verse service, Deutsche Telekom in Germany, Swisscom and Canadian operators Telus and Bell Canada. It is seen as an interim step towards full FTTH and in many cases services triple play services delivered using this approach has been proven to grow subscriber numbers and ARPU considerably.[15][16]
The simplest optical distribution network can be called direct fiber. In this architecture, each fiber leaving the central office goes to exactly one customer. Such networks can provide excellent bandwidth since each customer gets their own dedicated fiber extending all the way to the central office. However, this approach is about 10% more costly due to the amount of fiber and central office machinery required.[17]
The approach is generally favored by new entrants and competitive operators. A benefit of this approach is that it doesn't exclude any layer 2 networking technologies, be they Passive optical network, Active Optical Network, etc. From a regulatory point of view it leads to least implications as any form of regulatory remedy is still possible using this topology.[18]
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. There are two competing optical distribution network architectures which achieve this split: active optical networks (AONs) and passive optical networks (PONs).
Comparison showing how a typical active optical network handles downstream traffic differently than a typical
passive optical network. The type of active optical network shown is a
star network capable of
multicasting. The type of passive optical network shown is a star network having multiple splitters housed in the same cabinet.
Active optical networks rely on some sort of electrically powered equipment in Optical Distribution Network(ODN) to distribute the signal, such as a switch or router. Normally, optical signals need O-E-O transformation in ODN. Each signal leaving the central office is directed only to the customer for which it is intended.
Incoming signals from the customers avoid colliding at the intersection because the powered equipment there provides buffering. As of 2007, the most common type of active optical networks are called active Ethernet, a type of Ethernet in the first mile (EFM). Active Ethernet uses optical Ethernet switches to distribute the signal, thus incorporating the customers' premises and the central office into one giant switched Ethernet network.
Such networks are identical to the 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 campus. Each switching cabinet can handle up to 1,000 customers, although 400-500 is more typical.
This neighborhood equipment performs layer 2/layer 3 switching and routing, offloading full layer 3 routing to the carrier's central office. The IEEE 802.3ah standard enables service providers to deliver up to 100 Mbit/s full-duplex over one single-mode optical fiber to the premises depending on the provider. Speeds of 1Gbit/s are becoming commercially available.
A passive optical network (PON) is a point-to-multipoint, fiber to the premises network architecture in which unpowered optical splitters are used to enable a single optical fiber to serve multiple premises, typically 32-128. A PON configuration reduces the amount of fiber and central office equipment required compared with point to point architectures.
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). The OLTs "range" the ONUs in order to provide time slot assignments for upstream communication.
Once on private property, the signal typically travels the final distance to the end user's equipment using an electrical format.
A device called an Optical Network Terminal (ONT), also called an Optical Network Unit (ONU), converts the optical signal into an electrical signal. (ONT is an ITU-T term, whereas ONU is an IEEE term, but the two terms mean exactly the same thing.) Optical network terminals require electrical power for their operation, so some providers connect them to back-up batteries in case of power outages. Optical network units use thin film filter technology to convert between optical and electrical signals.
For fiber to the home and for some forms of fiber to the building, it is common for the building's existing phone systems, local area networks, and cable TV systems to connect directly to the ONT.
If all three systems cannot directly reach the ONT, it is possible to combine signals and transport them over a common medium. Once closer to the end-user, equipment such as a router, modem, and/or network interface controller can separate the signals and convert them into the appropriate protocol. For example, one solution for apartment buildings uses VDSL to combine data (and / or video) with voice.
With this approach, the combined signal travels through the building over the existing telephone wiring until it reaches the end-user's living space. Once there, a VDSL modem copies the data and video signals and converts them into Ethernet protocol. These are then sent over the end user's category 5 cable. A network interface module can then separate out the video signal and convert it into an RF signal that is sent over the end-user's coaxial cable.
The voice signal continues to travel over the phone wiring and is sent through DSL filters to remove the video and data signals. An alternative strategy allows data and / or voice to be transmitted over coaxial cable. In yet another strategy, some office buildings dispense with the telephone wiring altogether, instead using voice over Internet Protocol phones that can plug directly into the local area network.
General:
- ^ "FTTH Council - Definition of Terms". FTTH Council. August 11, 2006. http://www.ftthcouncil.org/sites/default/files/FTTH_definitions.pdf. Retrieved September 1, 2011.
- ^ a b c "FTTH Council - Definition of Terms". FTTH Council. January 9, 2009. http://ftthcouncil.eu/documents/Reports/FTTH-Definitions-Revision_January_2009.pdf. Retrieved September 1, 2011.
- ^ All multimode fiber is not created equal
- ^ http://www.telecompaper.com/research/ftth-networking-active-ethernet-versus-passive-optical-networking-and-point-to-point-vs-point-to-multipoint
- ^ http://nxtcommnews.com/ethernet/news08/active-ethernet-pon/
- ^ http://www.lightwaveonline.com/fttx/featured-articles/Is-Active-Ethernet-best-FTTH-option-for-Google-85219312.html
- ^ da Silva, Henrique (March, 2005), Optical Access Networks, Instituto de Telecomunicações, p. 10. Retrieved on 2007-03-25.
- ^ McCullough, Don (August, 2005), "Flexibility is key to successful fiber to the premises deployments", Lightwave 22 (8). Retrieved on 2010-01-27.
- ^ Analyst: AT&T may replace some FTTC with FTTP
- ^ http://www.nannimagazine.it/articolo/5353/Pirelli-Broadband-Solutions-e-il-partner-tecnologico-di-Fastweb-per-la-nuova-rete-a-banda-larga
- ^ http://www.telecomseurope.net/content/italy-gets-fiber-back-track
- ^ http://www.freevoipcallsolution.com/2010/08/pirelli-broadband-solutions-technology.html
- ^ http://fibertothewhatever.com/wp/news/telecom-italia-rolls-out-100-mbps-ftth-services-in-catania
- ^ http://www.pcpro.co.uk/news/broadband/370603/1gbit-sec-broadband-lands-in-london
- ^ http://ar2010.telekomaustria.com/en/facts_and_figures_2010.html
- ^ http://2010.swisscom-report.ch/en/financial-year-2010 [page 22]
- ^ The Economics of Next Generation Access
- ^ Developments In Fibre Technologies And Investment
- Portugal Brings Fibre To The Home - E&T Megazine, March 2011, J Baeta & N Mendes
- Fiber to the Home Council: Asia & The Pacific
- Fiber to the Home Council: Europe
- Fiber to the Home Council: Northern America
- Fiber to the Home Conference: Europe
- Fiber Optics LAN Section of the Telecommunications Industry Association
- Telephony Magazine — FTTH One-Stop news, metrics, technology, regulatory information and industry commentary
- Kingfisher International Application Notes Fiber Optic Testing information about FTTH backbone Terminology.
- Can You Say FTTN? Annie Lindstrom, Telephony Online, January 22, 2001
- SBC clarifies FTTN, FTTP plans Ed Gubbins, Telephony Online, November 12, 2004
- Network intelligence — optical networks of new generation August 2008
- FTTx Primer, July 2008
- Developments in Fibre Technologies and Investment, [OECD], 2008
- San Francisco Draft Fiber Study
- UOC University article
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