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An access network is a type of
telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
s
network Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics ...
which connects subscribers to their immediate
service provider A service provider (SP) is an organization that provides services, such as consulting, legal, real estate, communications, storage, and processing services, to other organizations. Although a service provider can be a sub-unit of the organization t ...
. It is contrasted with the
core network A backbone or core network is a part of a computer network which interconnects networks, providing a path for the exchange of information between different LANs or subnetworks. A backbone can tie together diverse networks in the same building ...
, which connects local providers to one another. The access network may be further divided between feeder plant or distribution network, and drop plant or edge network.


Telephone heritage

An access network, also referred to as an
outside plant In telecommunication, the term outside plant has the following meanings: *In civilian telecommunications, outside plant refers to all of the physical cabling and supporting infrastructure (such as conduit, cabinets, tower or poles), and any associ ...
, refers to the series of wires, cables and equipment lying between a consumer/business telephone termination point (the point at which a telephone connection reaches the customer) and the local
telephone exchange A telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital syst ...
. The local exchange contains banks of automated switching equipment which direct a call or connection to the consumer. The access network is perhaps one of the oldest assets a telecoms operator would own. In 2007–2008 many telecommunication operators experienced increasing problems maintaining the quality of the records which describe the network. In 2006, according to an independent
Yankee Group Yankee Group was an independent technology research and consulting firm, founded in 1970 by Howard Anderson. The firm "was one of the analyst industry’s most prestigious boutiques through the dot.com boom, with 70 analysts on the payroll in 2006 ...
report, globally operators experience profit leakage in excess of $17 billion each year. The access network is also perhaps the most valuable asset an operator owns since this is what physically allows them to offer a service. Access networks consist largely of pairs of copper wires, each traveling in a direct path between the exchange and the customer. In some instances, these wires may even consist of
aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
, which was commonly used in the 1960s and 1970s following a massive increase in the cost of copper. The price increase was temporary, but the effects of this decision are still felt today as
electromigration Electromigration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms. The effect is important in applications where high direc ...
within the aluminum wires can cause an increase in on-state resistance. This resistance causes degradation which can eventually lead to the complete failure of the wire to transport data. Access is essential to the future profitability of operators who are experiencing massive reductions in revenue from
plain old telephone service Plain old telephone service (POTS), or plain ordinary telephone system, is a retronym for voice-grade telephone service employing analog signal transmission over copper loops. POTS was the standard service offering from telephone companies from 1 ...
s, due in part to the opening of historically nationalized companies to competition, and in part to increased use of
mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
s and
voice over IP Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of speech, voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms In ...
(VoIP) services. Operators offered additional services such as
xDSL 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 ...
based broadband and IPTV (
Internet Protocol television Internet Protocol television (IPTV) is the delivery of television content over Internet Protocol (IP) networks. This is in contrast to delivery through traditional terrestrial, satellite, and cable television formats. Unlike downloaded media, ...
) to guarantee profit. The access network is again the main barrier to achieving these profits since operators worldwide have accurate records of only 40% to 60% of the network. Without understanding or even knowing the characteristics of these enormous copper spider webs, it is very difficult, and expensive to 'provision' (connect) new customers and assure the data rates required to receive next-generation services. Access networks around the world evolved to include more and more optical fiber technology. Optical fiber already makes up the majority of core networks and will start to creep closer and closer to the customer, until a full transition is achieved, delivering value-added services over
fiber to the home 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 opt ...
(FTTH).


Access process

The process of communicating with a network begins with an access attempt, in which one or more users interact with a communications system to enable initiation of user information transfer. An access attempt itself begins with issuance of an access request by an access originator. An access attempt ends either in successful access or in access failure - an unsuccessful access that results in termination of the attempt in any manner other than initiation of
user Ancient Egyptian roles * User (ancient Egyptian official), an ancient Egyptian nomarch (governor) of the Eighth Dynasty * Useramen, an ancient Egyptian vizier also called "User" Other uses * User (computing), a person (or software) using an ...
information transfer In telecommunications, information transfer is the process of moving messages containing user information from a source to a sink via a communication channel. In this sense, information transfer is equivalent to data transmission which highlights ...
between the intended source and destination (
sink A sink is a bowl-shaped plumbing fixture for washing hands, dishwashing, and other purposes. Sinks have a tap (faucet) that supply hot and cold water and may include a spray feature to be used for faster rinsing. They also include a drain to ...
) within the specified maximum access time. Access time is the time delay or latency between a requested access attempt and successful access being completed. In a
telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
s system, access time values are measured only on access attempts that result in successful access. Access failure can be the result of access outage, user
block Block or blocked may refer to: Arts, entertainment and media Broadcasting * Block programming, the result of a programming strategy in broadcasting * W242BX, a radio station licensed to Greenville, South Carolina, United States known as ''96.3 ...
ing, incorrect access, or access denial. Access denial (system blocking) can include: *Access failure caused by the issuing of a system blocking signal by a
communications system A communications system or communication system is a collection of individual telecommunications networks, transmission systems, relay stations, tributary stations, and terminal equipment usually capable of interconnection and interoperati ...
that does not have a
camp-on busy signal In telecommunication, the term camp-on busy signal has the following meanings: *A signal that informs a busy telephone user that another call originator is waiting for a connection. Synonym: ''call waiting'' *A teleprinter exchange Exchange m ...
feature. *Access failure caused by exceeding the maximum
access time Access time is the time delay or latency between a request to an electronic system, and the access being completed or the requested data returned * In a computer, it is the time interval between the instant at which an instruction control uni ...
and nominal system access time fraction during an access attempt.


Charging for access

An access charge is a charge made by a local exchange carrier for use of its local exchange facilities for a purpose such as the origination or termination of network traffic that is carried to or from a distant exchange by an
interexchange carrier An interexchange carrier (IXC), in U.S. legal and regulatory terminology, is a type of telecommunication company, commonly called a long-distance telephone company. It is defined as any carrier that provides services across multiple local access ...
. Although some access charges are billed directly to interexchange carriers, a significant percentage of all access charges are paid by the local end users.


Mobile access networks

*
GERAN GERAN is an abbreviation for GSM EDGE Radio Access Network. The standards for GERAN are maintained by the 3GPP (Third Generation Partnership Project). GERAN is a key part of GSM, and also of combined UMTS/GSM networks. GERAN is the radio part of ...
*
UTRAN UTRAN (short for "UMTS Terrestrial Radio Access Network''") is a collective term for the network and equipment that connects mobile handsets to the public telephone network or the Internet. It contains the base stations, which are called Node B's ...
*
E-UTRAN E-UTRA is the air interface of 3rd Generation Partnership Project ( 3GPP) Long Term Evolution (LTE) upgrade path for mobile networks. It is an acronym for Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access, also r ...
*
CDMA2000 CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling data between mobile phones and cell sites. It is developed by 3GPP2 as a backwards-compatible ...
*
GSM The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation ( 2G) digital cellular networks used by mobile devices such ...
*
UMTS The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
* 1xEVDO *
voLTE Voice over LTE (VoLTE) is an LTE high-speed wireless communication standard for mobile phones and data terminals, including Internet of things (IoT) devices and wearables. VoLTE has up to three times more voice and data capacity than older 3G U ...
*
Wi-Fi Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio wave ...
in*
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 WiMAX ...


Optical distribution network

A passive optical distribution network (PON) uses
single-mode optical fiber In fiber-optic communication, a single-mode optical fiber (SMF), also known as fundamental- or mono-mode, is an optical fiber designed to carry only a single mode of light - the transverse mode. Modes are the possible solutions of the Helmholtz ...
in the
outside plant In telecommunication, the term outside plant has the following meanings: *In civilian telecommunications, outside plant refers to all of the physical cabling and supporting infrastructure (such as conduit, cabinets, tower or poles), and any associ ...
,
optical splitter A beam splitter or ''beamsplitter'' is an optical device that splits a beam of light into a transmitted and a reflected beam. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding wide ...
s and optical distribution frames, duplexed so that both upstream and downstream signals share the same fiber on separate wavelengths. Faster PON standards generally support a higher split ratio of users per PON, but may also use reach extenders/amplifiers where extra coverage is needed.
Optical splitter A beam splitter or ''beamsplitter'' is an optical device that splits a beam of light into a transmitted and a reflected beam. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding wide ...
s creating a
point to multipoint In telecommunications, point-to-multipoint communication (P2MP, PTMP or PMP) is communication which is accomplished via a distinct type of one-to-many connection, providing multiple paths from a single location to multiple locations. Point-to ...
topology are also the same technology regardless of the type of PON system, making any PON network upgradable by changing the optical network terminals (ONT) and optical line terminal (OLT) terminals at each end, with minimal change to the physical network. Access networks usually also must support point-to-point technologies such as
Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...
, which bypasses any
outside plant In telecommunication, the term outside plant has the following meanings: *In civilian telecommunications, outside plant refers to all of the physical cabling and supporting infrastructure (such as conduit, cabinets, tower or poles), and any associ ...
splitter to achieve a dedicated link to the
telephone exchange A telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital syst ...
. Some PON networks use a "home run" topology where roadside cabinets only contain
patch panel A patch panel is a device or unit featuring a number of jacks, usually of the same or similar type, for the use of connecting and routing circuits for monitoring, interconnecting, and testing circuits in a convenient, flexible manner. Patch ...
s so that all splitters are located centrally. While a 20% higher capital cost could be expected, home run networks may encourage a more competitive wholesale market since providers' equipment can achieve higher use.


See also

*
Edge device An edge device is a device that provides an entry point into enterprise or service provider core networks. Examples include routers, routing switches, integrated access devices (IADs), multiplexers, and a variety of metropolitan area network (MA ...
*
Hierarchical internetworking model The Hierarchical internetworking model is a three-layer model for network design first proposed by Cisco. It divides enterprise networks into three layers: core, distribution, and access layer. Access layer End-stations and servers connect to t ...
*
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 ...
*
IP connectivity access network IP-CAN (or IP connectivity access network) is an access network that provides Internet Protocol (IP) connectivity. The term is usually used in cellular context and usually refers to 3GPP access networks such as GPRS or EDGE, but can be also used t ...
*
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 ...
*
Passive Optical Network A passive optical network (PON) is a fiber-optic telecommunications technology for delivering broadband network access to end-customers. Its architecture implements a point-to-multipoint topology in which a single optical fiber serves multiple en ...


References


External links

* {{cite web, title=The Network Story , publisher=British Telecom , url=http://www.btplc.com/Thegroup/Networkstory/html/slide.aspx_slide=1.html , year=2005 , url-status=dead , archive-url=https://web.archive.org/web/20100505215237/http://www.btplc.com/Thegroup/Networkstory/html/slide.aspx_slide%3D1.html , archive-date=5 May 2010 Interactive presentation introducing the technology and design of access networks Telecommunications infrastructure Network access Fiber to the premises