Fiber to the x

Depending on the conditions of use, the telecommunications industry distinguishes between several separate FTTX configurations:

• FTTN (Fiber to the Node) - fiber to the network node. Fiber optic ends in a street communication cabinet, possibly 1-2 km from the end user, with further copper laying - it can be xDSL or hybrid fiber-coaxial lines. ^[2] FTTN is often an intermediate step to full FTTB and is typically used to deliver an extended Triple Play telecommunications service package.
• FTTC / FTTK (Fiber to the Curb / Fiber to the kerb) - fiber to the neighborhood, block or group of houses. The option is very similar to FTTN, but a street cabinet or pillar is closer to the client’s premises and is usually within 300 meters — distances for broadband copper cables like wired Ethernet or IEEE 1901 power lines or Wi-Fi wireless technology. Sometimes FTTC is ambiguously called FTTP (fiber-to-the-pole, optics to the pillar), which causes confusion with the "Fiber to the premises system" (optics to the room system).
• FTTDP (Fiber To The Distribution Point) - fiber to the distribution point. It also looks like FTTC / FTTN, but one step closer. The fiber terminates a few meters from the end-user boundary and the last cable connection occurs in a junction box called a distribution point, which allows subscribers to provide speeds close to 1 gigabit . ^[3]
• FTTP (Fiber to the premises) - fiber to the premises. This abbreviation generalizes the terms FTTH and FTTB or is used in cases where the optical fiber is brought to where there are both houses and small businesses.
  • FTTB (Fiber to the Building) - the fiber reaches the boundary of the building, such as the foundation of an apartment building, basement or technical floor with the final connection of each living room using other methods as in FTTN or FTTP configurations.
  • FTTH (Fiber to the Home) - fiber to an apartment or a private house. The cable is brought to the border of the living area, for example, a communication box on the wall of the housing. Further, the operator’s services are provided to the subscriber via PON and PPPoE technology via FTTH networks. ^{[4] [5]}
• FTTD / FTTS (Fiber to the desktop, Fiber to the Subscriber) - an optical connection comes to the main computer room in the terminal or to the media converter near the client’s desktop.

• FTTE / FTTZ (Fiber to the telecom enclosure, fiber to the zone) is a type of cable system commonly used in a local area network when an optical connection is used from the server room to the workstation. These species are not included in the FTTX technology group, despite the similarity in names. ^[6]

To ensure coherence, especially when comparing FTTH penetration between countries, the three FTTH Councils - Europe, North America and Asia Pacific in 2006 agreed ^[7] on the definitions of FTTH and FTTB, and also clarified them in 2009 ^[8] , 2011 ^[9] and in February 2015. ^[10] The FTTH Council did not establish formal definitions for FTTC and FTTN.

FTTN

In this embodiment, the fiber-optic cable is connected to the network node and, therefore, can sometimes be confused with the FTTC connection when the optics are brought to an outdoor distribution cabinet or a pole carrying the cable, with further wiring in the neighborhood or nearby houses. ^[11] To end users, as a rule, further from such a cabinet are separate connections via coaxial cable or twisted pair . The territory served from one street distribution cabinet is usually located within a radius of less than 1.5 km and may include several hundred telematic service subscribers. If an area with a radius of less than 300 meters is served from the distribution cabinet, then this connection will apply to FTTC / FTTK. ^[12]

FTTN allows you to provide broadband communications services, such as high-speed Internet access. High-speed data transfer protocols similar to those used when working on broadband communication cables (usually DOCSIS ) or some types of xDSL are used from the end of the fiber to the consumer of services. The data transfer speed varies depending on the protocol used and how close the subscriber is to the distribution cabinet.

Unlike FTTP, the FTTN infrastructure often uses a coax cable or twisted pair cable to provide the last mile , which makes this option less expensive to deploy. However, in the long run, the potential bandwidth with this option will be very limited relative to the option with the end of the fiber closer to the subscriber.

A technical variation of this option is the hybrid optical-coax communication system used by cable television operators. Such a connection is also sometimes called FTTLA (Fiber to the last amplifier, optics to the last amplifier), when replacing the last amplifier with this connection in front of the subscriber (or group of subscribers).

FTTC

Fiber to a microdistrict, quarter or group of houses is a communication system, the essence of which is to launch a platform based on fiber-optic communication lines serving several subscribers. Each of these subscribers is connected to the platform with a coaxial cable or twisted pair. This can be an installed external device or a communication cabinet or a canopy. Typically, communication systems in which the fiber terminates less than 300 meters from the equipment installed in the user's premises are referred to as FTTC.

In this option, from the end of the fiber to the subscriber, as well as in FTTN, DOCSIS or xDSL is used.

Whenever possible, when laying a new cable, optical and copper ethernet cables are carried out immediately. The latter connects the regional communication center with the subscriber at speeds of 100 Mbit / s or 1 Gbit / s.

The development of power line communications is also referred to as FTTC. Using the IEEE 1901 protocol (or its predecessor, HomePlug AV ) allows you to transfer data from existing remote wiring closets to any AC outlet in your home over existing power grids at speeds up to 1 Gbit / s - network coverage is equivalent to Wi-Fi with the added advantage of one cables for power and data transmission.

The subtle but the main difference between FTTC and FTTN or FTTP will be the location of the wiring closet. In the FTTC connection option, for example, switching occurs from a cable-carrying pillar on the side of the road near the client’s house, while with FTTN the switching cabinet is far from the subscriber, and with FTTP, switching is directly in the customer service area.

Unlike FTTP, in the FTTC version, existing coaxial cables, twisted pair cable or power line communication can be used to create the last mile. An attempt to combine such existing cables under a single control protocol was the development of G.hn and IEEE P1905 standards .

Moving away from laying new cables and the associated costs, FTTC deployment costs are lower. However, this network option has historically had lower bandwidth potential than FTTP. In practice, the relative advantage of using optical fiber depends on the bandwidth available for the transport communication network , on billing restrictions that prevent the full load of the last mile throughput, on subscriber equipment, on the limitations of service and the cost of operating the optical fiber. All of these parameters can vary widely based on geographical location and type of structure.

FTTB (fiber to the building) - optical fiber to the building. In this architecture, the fiber reaches the switching equipment of the operator, located mainly on the border of the territory, which includes houses or enterprises. A single terminal is installed with the equipment, and from it either a copper cable is connected to the room or a wireless connection is used - in the room itself there is basically only one cable that connects to the computer. ^[13] FTTB architecture is most prevalent ^{[ where? ]} , since when building FTTx networks based on Ethernet , this is often the only technically feasible scheme. In addition, the difference between the FTTC and FTTB options is relatively small in the structure of the costs of creating an FTTx network, while the operating costs of operating the FTTB network are lower and the throughput is higher. FTTB architecture prevails in newly built houses and large telecom operators, while FTTH will be in demand only in new low-rise construction. This is primarily due to the significantly higher cost of its implementation compared to the cost of the FTTC / FTTB network.

FTTH (fiber to the home) - optical fiber to the home. A terminal is installed in the dwelling, and a cable from the terminal to the computer. This definition excludes those network architectures in which the optical fiber ends before reaching residential premises or office space and the line continues with a different physical environment than the optical one. ^[13]

Motorola experts were in favor of FTTH solutions. ^[1] They compare the life cycle of investments in any access technology and the correlated increase in access bandwidth requirements. The analysis shows that if the technical solutions that form the basis of the network access segment in 2005-2008 are unable to provide a speed of 100 Mbit / s in 2013 - 2015 , then obsolescence of the equipment will occur before the end of the investment cycle. The operator must take this data into account, otherwise he risks becoming vulnerable in the face of competitors as users strive to receive services of an increasingly higher class.

Alcatel-Lucent experts list the following benefits of the FTTH architecture:

• of all FTTx options, it provides the highest bandwidth;
• This is a fully standardized and most promising option;
• FTTH solutions provide mass customer service at a distance of up to 20 km from the communication center;
• they can significantly reduce operating costs - by reducing the area of ​​technical premises (necessary for equipment placement), reducing energy consumption and actually the costs of technical support. ^[one]

The simplest optical network architecture is direct fiber . With this method, each fiber in the cable from the premises of the telecom operator goes to one client. Such networks can provide excellent data transfer speeds, but they are significantly more expensive due to the irrational use of fibers and equipment serving the communication line. ^[14]

Straight fibers are typically provided to large corporate clients or government entities. The advantage is the ability to use the 2nd level of network technology, regardless of whether it is an active, passive or hybrid optical network.

In other cases (mass connections of subscribers), each fiber coming from the telecom operator serves many clients. It is called " shared fiber " ( English shared fiber ). In this case, the optics are brought as close as possible to the client, after which it is connected to the individual fiber going to the final consumer. In this connection, both active and passive optical networks are used.

Depending on the method of construction, optical networks are divided ^[15] into:

• active optical networks - with active active network equipment for signal amplification and transmission;
• passive optical networks - with splitters of optical signals;
• hybrid optical networks - using active and passive components at the same time.

Active Optical Network

It is based on the transmission of an optical signal by network electrical equipment that receives, amplifies and transmits these signals. It can be a switch , a router , a media converter - as a rule, optical signals in an active optical network are converted into electrical and vice versa. Each optical signal from the centralized equipment of a telecom operator goes only to that end user for which it is intended.

The incoming signals from the subscribers avoid collisions in a single fiber, as the electrical equipment provides buffering. Active ETTH equipment, which includes optical network switches with optics, and which serves to distribute the signal to subscribers, is used as the first mile from the operator’s equipment.

Such networks are identical to computer ethernet networks used in offices and educational institutions with the only exception that they are designed to connect houses and buildings to the central building of a telecom operator, and not to connect computers and printers in a limited space. Each distribution cabinet can serve up to 1000 subscribers, although it is usually limited to connecting 400-500 people.

Such nodal equipment provides switching of the second and third levels , as well as routing, thereby unloading the trunk router of the telecom operator and providing data transfer to its server room. The IEEE 802.3ah standard allows Internet service providers to provide speeds of up to 100 Mbit / s and full duplex over a single-mode optical fiber cable ( eng. Single-mode optical fiber ) connected via FTTH . 1 Gbit / s speeds are also becoming commercially available.

Passive Optical Network

A passive optical network is an FTTP network architecture with a point-to-multipoint connection based on non-volatile optical splitters (splitters) that allow up to 128 subscribers to be served on a single optical fiber. Compared to a straight- through connection, PON reduces the requirements for the optical cable and its provider's equipment. The downstream signal is transmitted from the equipment of the telecom operator to all subscribers sharing the communication line. Encryption is used to prevent traffic interception. Upstream signals from subscribers are combined into one stream using the multiple access protocol, as a rule, with time division of access .

Electrical equipment

When the communication line has already entered the client’s premises, the final distance to the client equipment, the signal, as a rule, already passes in the electric format.

This can be either a media converter or an optical network terminal (ONT, ITU-T term) or an optical network module (ONU, similar to the IEEE term), which converts an optical signal into an electric signal using a thin-film filter technology. These devices require electricity for their work, so they try to connect them to backup power sources to ensure uninterrupted operation in emergency cases and during power outages. Termination of an optical line by optical terminals or modules “directs” communication lines to allocate a time slot for the TDMA protocol and provide an upward communication stream (in the direction from the subscriber to the provider).

For the FTTH version and some types of FTTB, common to all connected buildings is the provision of telephone, LAN and cable television systems that connect to an optical network terminal or module. All three of these data transmission systems cannot be directly connected to the optical module, but it is possible to combine their signals and transmit in a single environment. Depending on which is closer to the user — a router, modem, or network card — the device can split the signal and convert it into a suitable protocol.

For example, when using VDSL technology, the combined signal is transmitted to the building via the existing wired connection and enters the living room, where the VDSL modem converts the data and video signal (television services) to the ethernet protocol, which is delivered to the terminal equipment via twisted pair cable . Next, the network interface module converts the video signal into a radio frequency signal transmitted to the terminal equipment via coaxial cable . The combined signal can also reach a telephone set connected via an ADSL splitter to separate the voice signal from the rest, or to an IP phone that can be connected to a local network.

• Internet access

• FTTx networks: building options
• Optics for the "first mile"