10G-PON
Encyclopedia
10G-PON is a 2010 computer network
ing standard for data links, capable of delivering shared Internet access
rates up to 10 Gbit/s (gigabits per second) over existing passive optics. Passive optical network
(PON) architecture has become a cost effective way to meet performance demands in access networks. Optical fibre is shared by many subscribers in a network known as FTTx
, often displacing the copper lines.
This is the ITU-T
's next generation standard following on from G-PON or Gigabit-capable PON. Fibre-to-the-home or Fibre-to-the-premise networks are used for last mile
telecommunications with splitters that connect each central transmitter to many subscribers. The 10 Gbit/s capacity is shared by all users connected to the same PON, and different multiplexing techniques prevent data frames from interfering with each other. Users have a network device that converts optical signals to the signals used in building wiring, such as Ethernet
and wired analogue plain old telephone service
. 10G-PON connections may also find uses in combining multiple fibre nodes within multi-tenant units and apartment
buildings.
completed parts of the standard in 2010.
services over IP of video, data and voice are often cited as driving user demand for heavier usage of broadband
that justifies PON investment. While RF overlay has been popular in some countries and minimises congestion caused by usage of video services, the convergence of HDTV and IPTV
could create demand for bandwidth that exceeds the capacity of gigabit services in future. Teleworking and video conferencing are other applications sometimes demanding such triple play capabilities.
Other bandwidth-intensive applications include video-conferencing, interactive video, online interactive gaming, peer-to-peer networking, karaoke-on-demand, IP video surveillance, and cloud applications where remote storage and computing resources provide online service on demand to users with thin-client local systems. Cloud applications could take advantage of local content hosting but 10GPON may encourage explosive development of innovative services that become feasible as users connect at faster speeds.
Business continuity
systems may also take advantage of 10GPON to enable cost effective real-time backup/replication of critical business systems, which may themselves be centralised services that support multiple sites. Other businesses may just need to connect several sites as a virtual private network
, effectively a virtual office, or may have e-commerce services that require business partners to have sufficient connectivity for constant database access.
Many of these applications are already growing in both popularity and demand for bandwidth.
G.987 is the standard for 10G-PON.
Asymmetric 10G-PON is specified as XG-PON1: 10 Gbit/s downstream and 2.5 Gbit/s upstream (nominal line rate of 9.95328 Gbit/s downstream and 2.48832 Gbit/s upstream).
Symmetric 10G-PON is also proposed as XG-PON2 with 10 Gbit/s upstream, but would require more expensive burst-mode laser
s on ONTs to deliver the upstream transmission speed.
Framing is "G-PON like" but uses different wavelengths from G-PON (using a WDM to separate them
) so that G-PON subscribers can be upgraded to 10G-PON incrementally while GPON users continue on the original OLT. The G-PON standard is G.984
. This compares to the IEEE 802.3av standard for 10G-EPON
based on Ethernet
, which has standardised upstream rates of both 1Gbps and 10Gbps. The 10 Gigabit PON wavelengths (1577 nm down / 1270 nm up) differ from GPON and EPON (1490 nm down /1310 nm up), allowing it to coexist on the same fibre with either of the Gigabit PONs.
Recommendation G.987 is a family that defines this access network standard (referred to as XG-PON). It comprises four recommendations:
(ONU) supplies network services from the PON to customer premises
, connecting customer-premises equipment
such as a home gateway or office firewall. An optical network terminal (ONT) is an ONU that functions as a demarcation point
that only services a single subscriber; e.g., a dwelling or office. ONU devices will supply Ethernet
to the building, and possibly POTS
, CATV signals to buildings wired for RF, and some may even be compatible with the emerging G.hn
home networking standard.
The ONU receives the downstream data, and also uses time slots allocated by the OLT to send the upstream traffic in burst-mode. TDMA
time slots prevent collisions with upstream traffic from other users on the same PON.
fibre-to-the-cellsite is another emerging application, but has extra synchronisation requirements. A specialised Cellular Backhaul Unit (CBU) would provide PON access for cellular network
s.
uplinks, allocates time slots for ONUs and ONTs to transmit upstream data, and transmits shared downstream data in broadcast-mode over the PON to users. Since 10GPON is designed to coexist with GPON devices, migration to a 10GPON capability could be done by upgrading the OLT and then migrating individual ONUs as needed.
Normally the OLT is on a card that slots into a chassis at the Central Office (CO), which uses special uplink cards for Ethernet
backhaul to the telecommunications provider's network and internet. Uplink cards on access equipment will likely use multiple Ethernet interfaces, although it remains to be seen what uplink speeds manufacturers will offer to support 10GPON access. Locating OLTs in outside plant
cabinets may be an option for reach extension as a way to minimise the number of central offices covering low population density areas.
ITU and IEEE are planning for convergence of their specifications at the physical layer in 10G that would allow for the shared chips, optics and hardware platforms, thus driving cost reductions for hardware manufacturers.
, optical splitter
s and optical distribution frame
s, duplexed so that both upstream and downstream share the same fibre on separate wavelengths. 10G-PON is no exception with similar reach to previous standards but supporting a higher split ratio of 128 users per PON, or more using reach extenders/amplifiers. Optical splitters creating a point to multipoint topology are also the same technology as those used by other PON systems. This means any PON network should be upgradable by changing the ONT and OLT terminals at each end, with no change to the fibre itself unless different connectors are chosen.
"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."
In an effort to extend the reach with support for 128 splits, the standard supports a range of optical budgets from 29 dB to 31 dB. A draft update to the standard is expected to further extend this to 33 dB and 35 dB budget classifications. A PON with a 35 dB optical budget could span 25 km or more and be shared/split among 128 subscribers.
Some ONTs can receive a broad range of optical spectrum from 1480 nm to 1580 nm, so making the 10G-PON downstream signal visible to G-PON receivers. As a result, ONTs must block the unwanted downstream signals with a wavelength blocking filter (WBF), a small passive optical device.
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
ing standard for data links, capable of delivering shared Internet access
Internet access
Many technologies and service plans for Internet access allow customers to connect to the Internet.Consumer use first became popular through dial-up connections in the 20th century....
rates up to 10 Gbit/s (gigabits per second) over existing passive optics. Passive optical network
Passive 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...
(PON) architecture has become a cost effective way to meet performance demands in access networks. Optical fibre is shared by many subscribers in a network known as FTTx
FTTX
Fiber to the x is a generic term for any broadband network architecture using optical fiber to replace all or part of the usual metal local loop used for last mile telecommunications...
, often displacing the copper lines.
This is the ITU-T
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
's next generation standard following on from G-PON or Gigabit-capable PON. Fibre-to-the-home or Fibre-to-the-premise networks are used for last mile
Last mile
The "last mile" or "last kilometer" is the final leg of delivering connectivity from a communications provider to a customer. The phrase is therefore often used by the telecommunications and cable television industries. The actual distance of this leg may be considerably more than a mile,...
telecommunications with splitters that connect each central transmitter to many subscribers. The 10 Gbit/s capacity is shared by all users connected to the same PON, and different multiplexing techniques prevent data frames from interfering with each other. Users have a network device that converts optical signals to the signals used in building wiring, 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....
and wired analogue 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....
. 10G-PON connections may also find uses in combining multiple fibre nodes within multi-tenant units and apartment
Multi-family residential
Multi-family residential is a classification of housing where multiple separate housing units for residential inhabitants are contained within one building or several buildings within one complex. A common form is an apartment building...
buildings.
Demand
As demand for network speed continues to grow, so new and faster technologies are spawned from the existing standards. 10G-PON is the next generation ultra-fast capability for G-PON providers, designed to coexist with installed G-PON user equipment on the same network, an example of Nielsen's law predicting demand for data downloads to double every year. The ITU-TITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
completed parts of the standard in 2010.
User Applications
Triple playTriple Play
A triple play is a baseball play in which three outs are made as a result of continuous action without any intervening errors between outs.Triple play may also refer to:...
services over IP of video, data and voice are often cited as driving user demand for heavier usage of broadband
Broadband
The term broadband refers to a telecommunications signal or device of greater bandwidth, in some sense, than another standard or usual signal or device . Different criteria for "broad" have been applied in different contexts and at different times...
that justifies PON investment. While RF overlay has been popular in some countries and minimises congestion caused by usage of video services, the convergence of HDTV and IPTV
IPTV
Internet Protocol television is a system through which television services are delivered using the Internet protocol suite over a packet-switched network such as the Internet, instead of being delivered through traditional terrestrial, satellite signal, and cable television formats.IPTV services...
could create demand for bandwidth that exceeds the capacity of gigabit services in future. Teleworking and video conferencing are other applications sometimes demanding such triple play capabilities.
Other bandwidth-intensive applications include video-conferencing, interactive video, online interactive gaming, peer-to-peer networking, karaoke-on-demand, IP video surveillance, and cloud applications where remote storage and computing resources provide online service on demand to users with thin-client local systems. Cloud applications could take advantage of local content hosting but 10GPON may encourage explosive development of innovative services that become feasible as users connect at faster speeds.
Business continuity
Business continuity
Business continuity is the activity performed by an organization to ensure that critical business functions will be available to customers, suppliers, regulators, and other entities that must have access to those functions. These activities include many daily chores such as project management,...
systems may also take advantage of 10GPON to enable cost effective real-time backup/replication of critical business systems, which may themselves be centralised services that support multiple sites. Other businesses may just need to connect several sites as a virtual private network
Virtual private network
A virtual private network is a network that uses primarily public telecommunication infrastructure, such as the Internet, to provide remote offices or traveling users access to a central organizational network....
, effectively a virtual office, or may have e-commerce services that require business partners to have sufficient connectivity for constant database access.
Many of these applications are already growing in both popularity and demand for bandwidth.
Standards
ITU-TITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
G.987 is the standard for 10G-PON.
Asymmetric 10G-PON is specified as XG-PON1: 10 Gbit/s downstream and 2.5 Gbit/s upstream (nominal line rate of 9.95328 Gbit/s downstream and 2.48832 Gbit/s upstream).
Symmetric 10G-PON is also proposed as XG-PON2 with 10 Gbit/s upstream, but would require more expensive burst-mode laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
s on ONTs to deliver the upstream transmission speed.
Framing is "G-PON like" but uses different wavelengths from G-PON (using a WDM to separate them
Wavelength-division multiplexing
In fiber-optic communications, wavelength-division multiplexing is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths of laser light...
) so that G-PON subscribers can be upgraded to 10G-PON incrementally while GPON users continue on the original OLT. The G-PON standard is G.984
G.984
ITU-T Recommendation G.984 is a family of recommendations that defines gigabit passive optical networks for telecommunications access networks...
. This compares to the IEEE 802.3av standard for 10G-EPON
10G-EPON
The 10 Gbit/s Ethernet Passive Optical Network standard, better known as 10G-EPON allows computer network connections over telecommunication provider infrastructure...
based on 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 has standardised upstream rates of both 1Gbps and 10Gbps. The 10 Gigabit PON wavelengths (1577 nm down / 1270 nm up) differ from GPON and EPON (1490 nm down /1310 nm up), allowing it to coexist on the same fibre with either of the Gigabit PONs.
G.987
ITU-TITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
Recommendation G.987 is a family that defines this access network standard (referred to as XG-PON). It comprises four recommendations:
- G.987: 10-Gigabit-capable passive optical network (XG-PON) systems: Definitions, Abbreviations, and Acronyms, 2010.
- G.987.1: General requirements of 10G-PON systems (approved 2010-01-13). Includes examples of services, user network interfaces (UNIs) and service node interfaces (SNIs), as well as the principal deployment configurations that are requested by network operators.
- G.987.2: Physical media dependent (PMD) layer specification (approved 2010-01-13, updated 2010-10-07). Describes a flexible optical fibre access network representing an evolutionary development from G.984.2, asymmetric only in the current version.
- G.987.3: Transmission convergence (TC) specifications (approved 2010-10-07).
G.988
There is also a companion ITU-T standard defining a management and control interface for administering optical network units, referred to by the G.987 recommendations.- G.988: ONU management and control interface (OMCI) specification (approved 2010-10-07).
ONU equipment
The optical network unitOptical Network Unit
An optical network unit is a device that transforms incoming optical signals into electronics at a customer's premises in order to provide telecommunications services over an optical fiber network.-Definition:...
(ONU) supplies network services from the PON to customer premises
On-premises wiring
In 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,...
, connecting customer-premises equipment
Customer-premises equipment
Customer-premises equipment or customer-provided equipment is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication channel at the demarcation point...
such as a home gateway or office firewall. An optical network terminal (ONT) is an ONU that functions as a 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...
that only services a single subscriber; e.g., a dwelling or office. ONU devices will supply 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....
to the building, and possibly 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....
, CATV signals to buildings wired for RF, and some may even be compatible with the emerging G.hn
G.hn
G.hn is the common name for a home network technology family of standards developed under the International Telecommunication Union's Standardization arm and promoted by the HomeGrid Forum...
home networking standard.
The ONU receives the downstream data, and also uses time slots allocated by the OLT to send the upstream traffic in burst-mode. TDMA
Time division multiple access
Time division multiple access is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot. This...
time slots prevent collisions with upstream traffic from other users on the same PON.
fibre-to-the-cellsite is another emerging application, but has extra synchronisation requirements. A specialised Cellular Backhaul Unit (CBU) would provide PON access for cellular network
Cellular network
A cellular network is a radio network distributed over land areas called cells, each served by at least one fixed-location transceiver known as a cell site or base station. When joined together these cells provide radio coverage over a wide geographic area...
s.
OLT and access nodes
The OLT (Optical Line Terminal) connects the PON to aggregated backhaulBackhaul (telecommunications)
In a hierarchical telecommunications network the backhaul portion of the network comprises the intermediate links between the core network, or backbone, of the network and the small subnetworks at the "edge" of the entire hierarchical network...
uplinks, allocates time slots for ONUs and ONTs to transmit upstream data, and transmits shared downstream data in broadcast-mode over the PON to users. Since 10GPON is designed to coexist with GPON devices, migration to a 10GPON capability could be done by upgrading the OLT and then migrating individual ONUs as needed.
Normally the OLT is on a card that slots into a chassis at the Central Office (CO), which uses special uplink cards for 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....
backhaul to the telecommunications provider's network and internet. Uplink cards on access equipment will likely use multiple Ethernet interfaces, although it remains to be seen what uplink speeds manufacturers will offer to support 10GPON access. Locating OLTs in 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...
cabinets may be an option for reach extension as a way to minimise the number of central offices covering low population density areas.
ITU and IEEE are planning for convergence of their specifications at the physical layer in 10G that would allow for the shared chips, optics and hardware platforms, thus driving cost reductions for hardware manufacturers.
Optical distribution network
PON Optical Distribution Networks use single mode optical fibre in the 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...
, 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 share the same fibre on separate wavelengths. 10G-PON is no exception with similar reach to previous standards but supporting a higher split ratio of 128 users per PON, or more using reach extenders/amplifiers. Optical splitters creating a point to multipoint topology are also the same technology as those used by other PON systems. This means any PON network should be upgradable by changing the ONT and OLT terminals at each end, with no change to the fibre itself unless different connectors are chosen.
"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."
In an effort to extend the reach with support for 128 splits, the standard supports a range of optical budgets from 29 dB to 31 dB. A draft update to the standard is expected to further extend this to 33 dB and 35 dB budget classifications. A PON with a 35 dB optical budget could span 25 km or more and be shared/split among 128 subscribers.
Some ONTs can receive a broad range of optical spectrum from 1480 nm to 1580 nm, so making the 10G-PON downstream signal visible to G-PON receivers. As a result, ONTs must block the unwanted downstream signals with a wavelength blocking filter (WBF), a small passive optical device.
Field trials
- In October 2010, Portugal Telecom reported a successful field trial of 10G-PON, transmitting 3D-TV content using XG-PON1 capabilities .
- Verizon also successfully completed a field trial of the pre-standard XG-PON2 (synchronous 10G-PON) capable of delivering a 10 Gbit/s broadband connection both downstream and upstream. In October 2010, at a Verizon customer’s business in Taunton, Mass., the XG-PON2 trial used the same optical fibre that provides that business with its existing FiOS network connection and services.
See also
- G.984G.984ITU-T Recommendation G.984 is a family of recommendations that defines gigabit passive optical networks for telecommunications access networks...
- Broadband Internet accessBroadband Internet accessBroadband Internet access, often shortened to just "broadband", is a high data rate, low-latency connection to the Internet— typically contrasted with dial-up access using a 56 kbit/s modem or satellite Internet with inherently high latency....
- Fiber-optic communicationFiber-optic communicationFiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information...
- Fiber to the premises by countryFiber to the premises by countryThis article lists the deployment of fiber to the premises by country.-Kenya: broadband residential and SOHO packages 1Mbps, 4Mbit/s and 8Mbit/s currently available in Nairobi’s Kileleshwa, Kilimani and Lavington suburbs...
- Next generation accessNext generation accessNext-generation access is term used by British Telecommunications describing a significant upgrade to the telecommunication access network replacing some or all of the copper cable with optical fibre...
- Hybrid fiber-coaxial
- fibre to the x
- Passive Optical NetworkPassive optical networkA 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...
- Triple play (telecommunications)Triple play (telecommunications)In telecommunications, triple play service is a marketing term for the provisioning of two bandwidth-intensive services, high-speed Internet access and television, and a less bandwidth-demanding service, telephone, over a single broadband connection. Triple play focuses on a combined business...
- Cloud computingCloud computingCloud computing is the delivery of computing as a service rather than a product, whereby shared resources, software, and information are provided to computers and other devices as a utility over a network ....
- Business continuityBusiness continuityBusiness continuity is the activity performed by an organization to ensure that critical business functions will be available to customers, suppliers, regulators, and other entities that must have access to those functions. These activities include many daily chores such as project management,...
- Wavelength-division multiplexingWavelength-division multiplexingIn fiber-optic communications, wavelength-division multiplexing is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths of laser light...
External links
- 10G-PON Tutorial
- FTTH Council Europe - FTTH Business Guide (Updated 24 Aug 2011)
- FTTH Council Europe - FTTH Handbook, Fourth Edition (Updated 24 Aug 2011)
- ITU-T GPON Summary
- Benjamin Reboul, FTTH Council APAC, “A Global Overview of FTTH”, FTTH Council APAC Annual Conference, May 25 2010 (Retrieved 08 Nov 2010)
- http://conference.vde.com/ecoc-2009/programs/documents/sp_stefandahlfort_ng%20access.pdf
- http://www.chaffeefiberoptics.com/nwsltr/Municipal%20and%20Utlity%20Guidebook.pdf
- Technologies and applications of Passive Optical Networks (PON)- Yukio Nakano
- A Chip Off the Old Block: System Requirements, Challenges, and Standards for Next-Generation PON
- Redundancy in G-PON systems