Outside plant
Encyclopedia
In telecommunication
, the term outside plant has the following meanings:
The CATV industry divides its fixed assets between head end
or inside plant
, and outside plant. The electrical power industry also uses the term outside plant to refer to electric power distribution
systems.
Network connections between devices such as computers, printers, and phones require a physical infrastructure to carry and process signals. Typically, this infrastructure will consist of:
The portion of this infrastructure contained within a building is the inside plant
, and the portion of this infrastructure connecting buildings or facilities is the outside plant. Where these two plants meet in a given structure is the demarcation point
.
Outside plant cabling, whether copper or fiber, is generally installed as aerial cable between poles, in an underground conduit system, or by direct burial.
Hardware associated with the outside plant must be either protected from the elements (for example, distribution frame
s are generally protected by a street side cabinet) or constructed with materials suitable for exposure to the elements. Installation of the outside plant elements often require construction of significant physical infrastructure, such as underground vaults. In older large installations, cabling is sometimes protected by air pressure systems designed to prevent water infiltration. While this is not a modern approach, the cost of replacement of the older cabling with sealed cabling is often prohibitively expensive. The cabling used in the outside plant must also be protected from electrical disturbances caused by lightning or voltage surges due to electrical shorts or induction.
(also known as the local loop
) providing basic telephone or DSL
services typically consists of the following elements:
Active equipment (such as a POTS
or DSL
line circuit) can then be connected to the line in order to provide service, but this is not considered part of outside plant.
There are generally four operating environments or classes covering all outside plant (OSP) applications, including wireless facilities.
Electronic equipment located in one or more of these environmental class locations are designed to withstand various environmental operating conditions resulting from climatic conditions that may include rain, snow, sleet, high winds, ice, salt spray, and sand storms. Since outside temperatures can possibly range from -40°C (-40°F) to 46°C (115°F), with varying degrees of solar loading, along with humidity levels ranging from below 10% up to 100%, significant environmental stresses within the enclosure or facility can be produced.
Telcordia GR-3108, Generic Requirements for Network Equipment in the Outside Plant (OSP) contains the most recent industry data regarding each Class described above. It also discusses what is currently happening in ATIS
and Underwriters Laboratories (UL)
The document also includes
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...
, 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 associated hardware (such as repeaterRepeaterA repeater is an electronic device that receives asignal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances.-Description:...
s) located between a demarcation pointDemarcation pointIn telephony, the demarcation point is the point at which the public switched telephone network ends and connects with the customer's on-premises wiring. It is the dividing line which determines who is responsible for installation and maintenance of wiring and equipment -- customer/subscriber, or...
in a switchingSwitchingLAN switching is a form of packet switching used in local area networks. Switching technologies are crucial to network design, as they allow traffic to be sent only where it is needed in most cases, using fast, hardware-based methods.- Layer 2 switching :...
facility and a demarcation point in another switching center or customer premisesOn-premises wiringIn telecommunication, on-premises wiring is customer-owned communications transmission lines. It is also called customer premises wiring . The transmission lines can be metallic or optical fiber, and may be installed within or between buildings.Premises wiring may consist of horizontal wiring,...
.
- In the United States, the DODUnited States Department of DefenseThe United States Department of Defense is the U.S...
defines outside plant as the communications equipment located between a main distribution frameMain distribution frameIn telephony, a main distribution frame is a signal distribution frame for connecting equipment to cables and subscriber carrier equipment . The MDF is a termination point within the local telephone exchange where exchange equipment and terminations of local loops are connected by jumper wires...
(MDF) and a userUser (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....
end instrumentEnd instrumentIn telecommunications an end instrument is an equipment connected to the wires at the end of a telecommunications link. In most cases, this is a telephone. End instruments that relate to DTE include Printers, Computers, barcode readers, Automated Teller Machines and the console ports of routers....
.
The CATV industry divides its fixed assets between head end
Head end
Head end may refer to:* A cable television headend, a master facility for receiving television signals for processing and distribution over a cable television system* gateway...
or inside plant
Inside plant
In telecommunication, the term inside plant has the following meanings:*All the cabling and equipment installed in a telecommunications facility, including the main distribution frame and all the equipment extending inward therefrom, such as PABX or central office equipment, MDF heat coil...
, and outside plant. The electrical power industry also uses the term outside plant to refer to electric power distribution
Electric power distribution
File:Electricity grid simple- North America.svg|thumb|380px|right|Simplified diagram of AC electricity distribution from generation stations to consumers...
systems.
Context
- Cables from wall outlets and jacks run to a communications closetsWiring closetA wiring closet is a small room commonly found in institutional buildings, such as schools and offices, where electrical connections are made. While they are used for many purposes, their most common use is for computer networking...
, sometimes referred to as station cable. - Cables connecting one communications closetWiring closetA wiring closet is a small room commonly found in institutional buildings, such as schools and offices, where electrical connections are made. While they are used for many purposes, their most common use is for computer networking...
to another, sometimes referred to as riser cable. - Racks containing telecommunications hardware, such as switchesNetwork switchA network switch or switching hub is a computer networking device that connects network segments.The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer of the OSI model...
, routers, and repeaterRepeaterA repeater is an electronic device that receives asignal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances.-Description:...
s. - Cables connecting one building to another.
- Exterior communications cabinets containing hardware outside of buildings.
- Radio transceivers used inside or outside buildings, such as wireless access pointWireless access pointIn computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards...
s, and hardware associated with them, such as antennas and towers.
The portion of this infrastructure contained within a building is the inside plant
Inside plant
In telecommunication, the term inside plant has the following meanings:*All the cabling and equipment installed in a telecommunications facility, including the main distribution frame and all the equipment extending inward therefrom, such as PABX or central office equipment, MDF heat coil...
, and the portion of this infrastructure connecting buildings or facilities is the outside plant. Where these two plants meet in a given structure is the demarcation point
Demarcation point
In telephony, the demarcation point is the point at which the public switched telephone network ends and connects with the customer's on-premises wiring. It is the dividing line which determines who is responsible for installation and maintenance of wiring and equipment -- customer/subscriber, or...
.
Outside plant cabling, whether copper or fiber, is generally installed as aerial cable between poles, in an underground conduit system, or by direct burial.
Hardware associated with the outside plant must be either protected from the elements (for example, 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 are generally protected by a street side cabinet) or constructed with materials suitable for exposure to the elements. Installation of the outside plant elements often require construction of significant physical infrastructure, such as underground vaults. In older large installations, cabling is sometimes protected by air pressure systems designed to prevent water infiltration. While this is not a modern approach, the cost of replacement of the older cabling with sealed cabling is often prohibitively expensive. The cabling used in the outside plant must also be protected from electrical disturbances caused by lightning or voltage surges due to electrical shorts or induction.
Example: Copper access network
In civilian telecommunications, the copper access networkAccess network
An access network is that part of a telecommunications network which connects subscribers to their immediate service provider. It is contrasted with the core network, which connects local providers to each other...
(also known as the local loop
Local loop
In telephony, the local loop is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the carrier or telecommunications service provider's network...
) providing basic telephone or DSL
Digital Subscriber Line
Digital subscriber line is a family of technologies that provides digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop. In telecommunications marketing, the term DSL is widely understood to mean Asymmetric Digital Subscriber Line ,...
services typically consists of the following elements:
- In-house wiring that connects customer premises equipment to the demarcation pointDemarcation pointIn telephony, the demarcation point is the point at which the public switched telephone network ends and connects with the customer's on-premises wiring. It is the dividing line which determines who is responsible for installation and maintenance of wiring and equipment -- customer/subscriber, or...
, usually in residential installations contained in a weather protected box. - One or more twisted pairTwisted pairTwisted pair cabling is a type of wiring in which two conductors are twisted together for the purposes of canceling out electromagnetic interference from external sources; for instance, electromagnetic radiation from unshielded twisted pair cables, and crosstalk between neighboring pairs...
s, called a drop wire. The drop wires typically connect to a splice case, located in line for aerial cables, or in a small weather protected case for underground wiring, where the local cabling is connected to a secondary feeder line. These cables contain fifty or more twisted pairs. - Secondary feeder lines run to a streetside cabinet containing a distribution frameDistribution frameIn 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...
called a Serving Area InterfaceServing area interfaceThe serving area interface or service area interface often called B-box, cross-connect box, cross box, ped , or access point is an outdoor telecommunications cabinet usually mounted on the ground on cable right-of-ways, but sometimes also on telephone poles...
(SAI). - The SAIServing area interfaceThe serving area interface or service area interface often called B-box, cross-connect box, cross box, ped , or access point is an outdoor telecommunications cabinet usually mounted on the ground on cable right-of-ways, but sometimes also on telephone poles...
is connected to the main distribution frameMain distribution frameIn telephony, a main distribution frame is a signal distribution frame for connecting equipment to cables and subscriber carrier equipment . The MDF is a termination point within the local telephone exchange where exchange equipment and terminations of local loops are connected by jumper wires...
, located at a Telephone exchangeTelephone exchangeIn the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...
or other switching facility, by one or more primary feeder lines which contain hundreds of copper twisted pairs. An SAIServing area interfaceThe serving area interface or service area interface often called B-box, cross-connect box, cross box, ped , or access point is an outdoor telecommunications cabinet usually mounted on the ground on cable right-of-ways, but sometimes also on telephone poles...
may also contain a Digital subscriber line access multiplexerDigital subscriber line access multiplexerA digital subscriber line access multiplexer is a network device, located in the telephone exchanges of the telecommunications operators. It connects multiple customer digital subscriber line interfaces to a high-speed digital communications channel using multiplexing techniques...
(DSLAM) supporting DSLDigital Subscriber LineDigital subscriber line is a family of technologies that provides digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop. In telecommunications marketing, the term DSL is widely understood to mean Asymmetric Digital Subscriber Line ,...
service.
Active equipment (such as a POTS
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....
or DSL
Digital Subscriber Line
Digital subscriber line is a family of technologies that provides digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop. In telecommunications marketing, the term DSL is widely understood to mean Asymmetric Digital Subscriber Line ,...
line circuit) can then be connected to the line in order to provide service, but this is not considered part of outside plant.
Protecting Equipment in the Outside Plant
The environment can play a large role in the quality and lifespan of equipment used in the outside plant. It is critical that environmental testing criteria as well as design and performance requirements be defined for this type of equipment.There are generally four operating environments or classes covering all outside plant (OSP) applications, including wireless facilities.
- Class 1: Equipment in a Controlled Environment
- Class 2: Protected Equipment in Outside Environments
- Class 3: Protected Equipment in Severe Outside Environments
- Class 4: Products in an Unprotected Environment
Electronic equipment located in one or more of these environmental class locations are designed to withstand various environmental operating conditions resulting from climatic conditions that may include rain, snow, sleet, high winds, ice, salt spray, and sand storms. Since outside temperatures can possibly range from -40°C (-40°F) to 46°C (115°F), with varying degrees of solar loading, along with humidity levels ranging from below 10% up to 100%, significant environmental stresses within the enclosure or facility can be produced.
Telcordia GR-3108, Generic Requirements for Network Equipment in the Outside Plant (OSP) contains the most recent industry data regarding each Class described above. It also discusses what is currently happening in ATIS
Alliance for Telecommunications Industry Solutions
The Alliance for Telecommunications Industry Solutions is a standards organization that develops technical and operational standards for the telecommunication industry. ATIS is headquartered in Washington, D.C....
and Underwriters Laboratories (UL)
Underwriters Laboratories
Underwriters Laboratories Inc. is an independent product safety certification organization. Established in 1894, the company has its headquarters in Northbrook, Illinois. UL develops standards and test procedures for products, materials, components, assemblies, tools and equipment, chiefly dealing...
The document also includes
- environmental criteria such as operating temperatures, humidity, particulate contamination, pollution exposure, and heat dissipation
- mechanical criteria such as structural requirements, packaging, susceptibility to vibration, earthquake, and handling
- electrical protection and safety including protection from lightning surges, AC power induction and faults, and Electromagnetic Interference (EMI), and DC power influences