Access network
Encyclopedia
An access network is that part of a telecommunication
s network
which connects subscribers to their immediate service provider
. It is contrasted with the core network
, (for example the Network Switching Subsystem
in GSM) which connects local providers to each other. The access network may be further divided between feeder plant or distribution network, and drop plant or edge network.
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
. The local exchange contains banks of automated switching equipment to direct a call or connection to the consumer. The access network is perhaps one of the oldest assets a telecoms operator owns, and is constantly evolving, growing as new customers are connected, and as new services are offered. This makes the access network one of the most complex networks in the world to maintain and keep track of.
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
report, globally operators experience profit leakage in excess of €15 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 be aluminum, the use of which was common in the 1960s and 1970s following a massive increase in the cost of copper. As it happened, the price increase was temporary, but the effect of this decision is still felt today because the aluminum wires oxidize and lose their ability to carry large quantities of data.
Access is essential to the future profitability of operators who are experiencing massive reductions in revenue from plain old telephone service
s, due in part to the opening of historically nationalized companies to competition, and in part to increased use of mobile phone
s and voice over IP
(VoIP) services. Operators offered additional services such as xDSL based broadband and IPTV (Internet Protocol Television) to guarantee profit. The access network is again the main barrier to achieving these profits since operators world wide 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 fibre 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 (FTTH).
to enable initiation of user information transfer. An access attempt itself begins with an 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
information transfer
between the intended source and destination (sink
) within the specified maximum access time.
Access failure can be the result of access outage, user blocking
, incorrect access, or access denial
. Access denial (system blocking) can include:
for use of its local exchange facilities for a purpose such as the origination or termination of traffic
that is carried to or from a distant exchange by an interexchange carrier
.
Although some access charges are billed directly to local end users, a very large part of all access charges is paid by interexchange carriers.
distribution network (PON) uses single mode optical fibre in the outside plant
, optical splitter
s and optical distribution frame
s, duplexed so that both upstream and downstream signals share the same fibre 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 splitters creating a point to multipoint topology are also the same technology regardless of the type of PON system, making any PON network upgradable by changing the ONT and 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
, which bypasses any outside plant
splitter to achieve a dedicated link to the Central Office. Some PON networks use a "home run" topology where roadside cabinets only contain patch panel
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 utilisation.
"An Optical Distribution Network (ODN) being installed today will likely need to support four or more generations of PON over its expected 30 – 40 year life... The fibre should enable maximum flexibility to support any potential new PON technology, be protected with proven, reliable cabling making it easy to install and reliable, and be joined by advanced, low labor and low loss connectivity. The cost of the ODN materials (fibre, cable, and connectivity) at only about 8% comprises a surprisingly small portion of the total network cost."
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
s network
Telecommunications network
A telecommunications network is a collection of terminals, links and nodes which connect together to enable telecommunication between users of the terminals. Networks may use circuit switching or message switching. Each terminal in the network must have a unique address so messages or connections...
which connects subscribers to their immediate service provider
Service provider
A service provider is an entity that provides services to other entities. Usually, this refers to a business that provides subscription or web service to other businesses or individuals. Examples of these services include Internet access, Mobile phone operators, and web application hosting...
. It is contrasted with the core network
Core network
A core network, or network core, is the central part of a telecommunication network that provides various services to customers who are connected by the access network. One of the main functions is to route telephone calls across the PSTN....
, (for example the Network Switching Subsystem
Network Switching Subsystem
Network switching subsystem is the component of a GSM system that carries out call switching and mobility management functions for mobile phones roaming on the network of base stations...
in GSM) which connects local providers to each other. The access network may be further divided between feeder plant or distribution network, and drop plant or edge network.
Telephone heritage
An access network or outside plantOutside 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 , and any associated hardware located between a demarcation point in a switching facility and a demarcation...
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
Telephone exchange
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...
. The local exchange contains banks of automated switching equipment to direct a call or connection to the consumer. The access network is perhaps one of the oldest assets a telecoms operator owns, and is constantly evolving, growing as new customers are connected, and as new services are offered. This makes the access network one of the most complex networks in the world to maintain and keep track of.
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
Yankee Group, a Massachusetts company, sells advice and market-research information relating to information technology.-History:Founded in 1970, the Yankee Group emerged as the first independent technology research and consulting firm...
report, globally operators experience profit leakage in excess of €15 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 be aluminum, the use of which was common in the 1960s and 1970s following a massive increase in the cost of copper. As it happened, the price increase was temporary, but the effect of this decision is still felt today because the aluminum wires oxidize and lose their ability to carry large quantities of 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
Plain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in many parts of the world....
s, due in part to the opening of historically nationalized companies to competition, and in part to increased use of mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
s and voice over IP
Voice over IP
Voice over Internet Protocol is a family of technologies, methodologies, communication protocols, and transmission techniques for the delivery of voice communications and multimedia sessions over Internet Protocol networks, such as the Internet...
(VoIP) services. Operators offered additional services such as xDSL based broadband and IPTV (Internet Protocol Television) to guarantee profit. The access network is again the main barrier to achieving these profits since operators world wide 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 fibre 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 (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 systemCommunications system
In telecommunication, a communications system is a collection of individual communications networks, transmission systems, relay stations, tributary stations, and data terminal equipment usually capable of interconnection and interoperation to form an integrated whole...
to enable initiation of user information transfer. An access attempt itself begins with an 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
User (telecommunications)
In telecommunications, a user is a person, organization, or other entity that employs the services provided by a telecommunication system, or by an information processing system, for transfer of information....
information transfer
Information transfer
In telecommunications, information transfer is the process of moving messages containing user information from a source to a sink.Note: The information transfer rate may or may not be equal to the transmission modulation rate.-See also:...
between the intended source and destination (sink
Sink
A sink is a bowl-shaped plumbing fixture used for washing hands, for dishwashing or other purposes. Sinks generally have taps that supply hot and cold water and may include a spray feature to be used for faster rinsing...
) within the specified maximum access time.
Access failure can be the result of access outage, user blocking
Blocking
Blocking may refer to:- Telecommunications and computing :*Block , a sequence of bytes or bits, having a nominal length*Block , technical measures to restrict users' access to certain internet resources...
, incorrect access, or access denial
Denial of request
Denial of request is the refusal of one party to grant the request of another. Some acts that can be considered denial may include the refusal of a person or a group of people representing a company, organization, or government agency to provide what a client or one seeking to be a client has...
. Access denial (system blocking) can include:
- Access failure caused by the issuing of a system blocking signal by a communications systemCommunications systemIn telecommunication, a communications system is a collection of individual communications networks, transmission systems, relay stations, tributary stations, and data terminal equipment usually capable of interconnection and interoperation to form an integrated whole...
that does not have a callSystem callIn computing, a system call is how a program requests a service from an operating system's kernel. This may include hardware related services , creating and executing new processes, and communicating with integral kernel services...
-originator camp-on feature. - Access failure caused by exceeding the maximum access timeAccess timeAccess time is the time delay or latency between a request to an electronic system, and the access being completed or the requested data returned....
and nominal system access time fraction during an access attempt.
Charging for access
An access charge is a charge made by a local exchange carrierLocal exchange carrier
Local Exchange Carrier is a regulatory term in telecommunications for the local telephone company.In the United States, wireline telephone companies are divided into two large categories: long distance and local...
for use of its local exchange facilities for a purpose such as the origination or termination of traffic
Network traffic
Network traffic is data in a network. In computer networks, the data is encapsulated in packets.*Network traffic control*Network traffic measurement*Network traffic simulation...
that is carried to or from a distant exchange by an interexchange carrier
Interexchange carrier
An Interexchange Carrier is a U.S. legal and regulatory term for a telecommunications company, commonly called a long-distance telephone company, such as MCI , Sprint and the former AT&T in the United States...
.
Although some access charges are billed directly to local end users, a very large part of all access charges is paid by interexchange carriers.
Mobile access networks
- GERANGERANGERAN is an abbreviation for GSM EDGE Radio Access Network. The standards for GERAN are maintained by the 3GPP...
- UTRANUtranUtran is a census town in Surat district in the Indian state of Gujarat.-Geography:Utran is located at . It has an average elevation of 12 metres .-Demographics:...
- CDMA2000CDMA2000CDMA2000 is a family of 3G mobile technology standards, which use CDMA channel access, to send voice, data, and signaling data between mobile phones and cell sites. The set of standards includes: CDMA2000 1X, CDMA2000 EV-DO Rev. 0, CDMA2000 EV-DO Rev. A, and CDMA2000 EV-DO Rev. B...
- GSM
- UMTS
- 1xEVDO
- Wi-FiWi-FiWi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
- WiMAXWiMAXWiMAX is a communication technology for wirelessly delivering high-speed Internet service to large geographical areas. The 2005 WiMAX revision provided bit rates up to 40 Mbit/s with the 2011 update up to 1 Gbit/s for fixed stations...
Optical distribution network
A passive opticalPassive optical network
A passive optical network 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 16-128. A PON consists of an optical line terminal at the service provider's central...
distribution network (PON) uses single mode optical fibre in the outside plant
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 , and any associated hardware located between a demarcation point in a switching facility and a demarcation...
, optical splitter
Beam splitter
A beam splitter is an optical device that splits a beam of light in two. It is the crucial part of most interferometers.In its most common form, a rectangle, it is made from two triangular glass prisms which are glued together at their base using Canada balsam...
s and optical distribution frame
Distribution frame
In telecommunications, a distribution frame is a passive device which terminates cables, allowing arbitrary interconnections to be made.For example, the Main Distribution Frame located at a telephone central office terminates the cables leading to subscribers on the one hand, and cables leading to...
s, duplexed so that both upstream and downstream signals share the same fibre 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 splitters creating a point to multipoint topology are also the same technology regardless of the type of PON system, making any PON network upgradable by changing the ONT and 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
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
, which bypasses any outside plant
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 , and any associated hardware located between a demarcation point in a switching facility and a demarcation...
splitter to achieve a dedicated link to the Central Office. Some PON networks use a "home run" topology where roadside cabinets only contain patch panel
Patch panel
A patch panel or patch bay is a panel, typically rackmounted, that houses cable connections. One typically shorter patch cable will plug into the front side, whereas the back holds the connection of a much longer and more permanent cable...
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 utilisation.
"An Optical Distribution Network (ODN) being installed today will likely need to support four or more generations of PON over its expected 30 – 40 year life... The fibre should enable maximum flexibility to support any potential new PON technology, be protected with proven, reliable cabling making it easy to install and reliable, and be joined by advanced, low labor and low loss connectivity. The cost of the ODN materials (fibre, cable, and connectivity) at only about 8% comprises a surprisingly small portion of the total network cost."