Fiber to the x
Fiber to the x (FTTX; also spelled "fibre") or fiber in the loop is a generic term for any broadband network architecture using optical fiber to provide all or part of the local loop used for last mile 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.[1]
"Fiber broadband" redirects here. For the overhead version of data and internet transmission, see Broadband over power lines.
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.[2]
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."[3]
A similar network called a hybrid fiber-coaxial (HFC) network is used by cable television operators but is usually not synonymous with "fiber In the loop", although similar advanced services are provided by the HFC networks. Fixed wireless and mobile wireless technologies such as Wi-Fi, WiMAX and 3GPP Long Term Evolution (LTE) are an alternative for providing Internet access.
The telecommunications industry differentiates between several distinct FTTX configurations. The terms in most widespread use today are:
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,[9] with an update in 2009,[10] 2011[11] and another in 2015.[12] The FTTH Councils do not have formal definitions for FTTC and FTTN.
Benefits[edit]
While fiber optic cables can carry data at high speeds over long distances, copper cables used in traditional telephone lines and ADSL cannot. For example, the common form of Gigabit Ethernet (1 Gbit/s) runs over relatively economical category 5e, category 6 or 6A unshielded twisted-pair copper cabling but only to 100 m (330 ft). 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.[13]
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 (VDSL) at downstream rates of 80 Mbit/s, but this falls extremely quickly when the distance exceeds 100 meters.
Fiber to the premises (FTTP) is a form of fiber-optic communication delivery in which an optical fiber is run in an optical distribution network 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 without reaching the premises.
Fiber to the premises can be categorized according to where the optical fiber ends:
An apartment 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 (either only to the ground floor or to each floor), it is FTTB.
Optical distribution networks[edit]
Direct fiber[edit]
The simplest optical distribution network architecture is direct fiber: each fiber leaving the central office goes to exactly one customer. These networks can support a lot of bandwidth, but they cost more because of the fiber and the equipment in the central office.[31]
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.[32]
[edit]
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.