Differences between EPON and GPON

PON is the abbreviation of passive optical network, which only uses fiber and passive components like fiber splitter and combiner. EPON (Ethernet PON) and GPON (Gigabit PON) are the most important versions of passive optical networks, widely used for Internet access, voice over Internet protocol (VoIP), and digital TV delivery in metropolitan areas. Today we are going to talk about the differences between EPON and GPON.
Technology Comparison of EPON and GPON
EPON is based on the Ethernet standard 802.3 that can support the speed of 1.25 Gbit/s in both the downstream and upstream directions. It is well-known as the solution for the “first mile” optical access network. While GPON, based on Gigabit technology, is designated as ITU-T G.983 which can provide for 622 Mbit/s downstream and 155 Mbit/s upstream. GPON is an important approach to enable full service access network. Its requirements were set force by the Full Service Access Network (FASN) group, which was later adopted by ITU-T as the G.984.x standards–an addition to ITU-T recommendation, G.983, which details broadband PON (BPON).
As the parts of PON, they have something in common. For example, they both can be accepted as international standards, cover the same network topology methods and FTTx applications, and use WDM (wavelength-division multiplexing) with the same optical frequencies as each other with a third party wavelength; and provide triple-play, Internet Protocol TV (IPTV) and cable TV (CATV) video services.
Costs Comparison
No matter in a GPON or in an EPON, the optical line terminal (OLT), optical network unit (ONU) and optical distribution network (ODN) are the indispensable parts, which are the decisive factor of the costs of GPON and EPON deployments.
The cost of OLT and ONT is influenced by the ASIC (application specific integrated circuit) and optic module. Recently, the chipsets of GPON are mostly based on FPGA (field-programmable gate array), which is more expensive than the EPON MAC layer ASIC. On the other hand, the optic module’s price of GPON is also higher than EPON’s. When GPON reaches deployment stage, the estimated cost of a GPON OLT is 1.5 to 2 times higher than an EPON OLT, and the estimated cost of a GPON ONT will be 1.2 to 1.5 times higher than an EPON ONT.
We all know that the ODN is made up of fiber cable, cabinet, optical splitter, connector, and etc. In the case of transmitting signals to the same number of users, the cost of EPON and GPON would be the same.
Summary
Nowadays, since many experts have different opinions on EPON and GPON. Thus, there is no absolute answer to determine which is better. But one thing is clear: PON, which possesses the low cost of passive components, has made great strides driven by the growing demand for faster Internet service and more video. Also, fiber deployments will continue expanding at the expense of copper, as consumer demands for “triple-play” (video, voice and data) grow.

Choosing correct fiber optic cable and installation issues

by http://www.fiber-mart.com

When designing optical fiber network choosing correct fiber optic cable is critical for success of the project.
First, it is important to match ratings between equipment and cabling. In other, words choose 800 nm cable if using 800 nm equipment. It is especially important to check correct cables, in case you plan to use sophisticated DWDM muxes, some cheaper optical cables might have big attenuation at wavelength windows you will need.
The locale of the cable is also very important. Inside cable would perform poorly when installed outside, since it is lacking the protection features necessary, for outside use. Important to remember safety of personnel – un-terminated cable should not be touched with bare hands because of the danger of glass slivers, and should not be looked at directly – it could harm human vision。
In order to avoid any unnecessary danger for people, fiber-optic cable is typically terminated in some kind of enclosure.
One of the options for enclosure is patch panel. It gets multiple fiber-optic cables as input and allows interconnect them inside enclosure with short interconnect cables. Another option for optical enclosure is the fiber distribution panel.
It allows interconnections the same way as fiber patch panel. The difference is in connectors – they are more permanent. It is commonly used for splitting multi-fiber cables into individual cables.
There are several important factors affecting the performance and might decrease quality of the signal. First of them is attenuation or loss of data carrying  signal power. Attenuation is measured in dBs. More dBs represent higher signal loss (3dB equals 50% signal power loss). Cables with high attenuation specification are having shorter maximum transmittance distances. Things like dirty fiber end faces, imperfection of fiber, excessive bending, poor installation, and excessive stretching affect attenuation directly.
Another factor affecting performance is the acceptance angle – an angle at which laser could transmit signal through fiber successfully. Greater acceptance angle between two or more signals in multimode fiber result in negative performance of cable.
Characteristics like Numerical Aperture, Modal Dispersion and Bandwidth, and Chromatic Dispersion result from acceptance angle and affect overall performance. They are related to refractive specifications of the core, transmission delays and fiber bandwidth, and wavelength distribution respectively.
Specifically, for FTTx networks, choosing a cable is important, since you will usualy need transmit 3 wavelengths, lik

Introduction to Passive Optical Network (PON)

Seen from the entire network structures,the Passive Optical Network (PON) market is in a high-growth period due to the ongoing deployments of Fiber to the Home (FTTH) networks

Seen from the entire network structures,the Passive Optical Network (PON) market is in a high-growth period due to the ongoing deployments of Fiber to the Home (FTTH) networks.today, we mainly Introduce Passive Optical Network (PON).

What does Passive Optical Network (PON)mean?

A passive optical network (PON) is a cabling system that uses optical fibers and optical splitters to deliver services to multiple access points. A PON system can be fiber-to-the-curb (FTTC), fiber-to-the-building (FTTB) or fiber-to-the-home (FTTH). A PON system consists of optical line termination (OLT) at the communication provider’s end and a number of optical network units (ONUs) at the user’s end. The term “passive” simply means that there are no power requirements while the network is up and running.

 

A PON consists of an optical line terminal (OLT) at the service provider’s central office (hub) and a number of optical network units (ONUs) or optical network terminals (ONTs), near end users. A PON reduces the amount of fiber and central office equipment required compared with point-to-point architectures. A passive optical network is a form of fiber-optic access network.In most cases, downstream signals are broadcast to all premises sharing multiple fibers. Encryption can prevent eavesdropping.upstream signals are combined using a multiple access protocol, usually time division multiple access (TDMA).

What is PON 2.jpg.png

 

Feature

A PON takes advantage of wavelength division multiplexing (WDM), using one wavelength for downstream traffic and another for upstream traffic on a single mode fiber (ITU-T G.652). BPON, EPON, GEPON, and GPON have the same basic wavelength plan and use the 1490 nanometer (nm) wavelength for downstream traffic and 1310 nm wavelength for upstream traffic. most common is 28 dB of loss budget for both BPON and GPON, but products have been announced using less expensive optics as well. 28 dB corresponds to about 20 km with a 32-way split. Forward error correction (FEC) may provide for another 2–3 dB of loss budget on GPON systems. As optics improve, the 28 dB budget will likely increase. Although both the GPON and EPON protocols permit large split ratios (up to 128 subscribers for GPON, up to 32,768 for EPON), in practice most PONs are deployed with a split ratio of 1:32 or smaller.

A PON consists of a central office node, called an optical line terminal (OLT), one or more user nodes, called optical network units (ONUs) or optical network terminals (ONTs), and the fibers and splitters between them, called the optical distribution network (ODN). “ONT” is an ITU-T term to describe a single-tenant ONU. In multiple-tenant units, the ONU may be bridged to a customer premises device within the individual dwelling unit using technologies such as Ethernet over twisted pair, G.hn (a high-speed ITU-T standard that can operate over any existing home wiring – power lines, phone lines and coaxial cables) or DSL. An ONU is a device that terminates the PON and presents customer service interfaces to the user. Some ONUs implement a separate subscriber unit to provide services such as telephony, Ethernet data, or video.

An OLT provides the interface between a PON and a service provider′s core network. These typically include:

  • IP traffic over Fast Ethernet, gigabit Ethernet, or 10 Gigabit Ethernet;
  • Standard TDM interfaces such as SDH/SONET;
  • ATM UNI at 155–622 Mbit/s.

functions are separated into two parts:

  • The ONU, which terminates the PON and presents a converged interface—such as DSL, coaxial cable, or multiservice Ethernet—toward the user;
  • Network termination equipment (NTE), which inputs the converged interface and outputs native service interfaces to the user, such as Ethernet and POTS.

 

The Benefits of PON

As early as before, PONs began appearing in corporate networks. Users were adopting these networks because they were cheaper, faster, lower in power consumption, easier to provision for voice, data and video, and easier to manage, since they were originally designed to connect millions of homes for telephone, Internet and TV services.Passive Optical Networks (PON) provide high-speed, high-bandwidth and secure voice, video and data service delivery over a combined fiber network.

The main benefits of PON as below:

  • Lower network operational costs
  • Elimination of Ethernet switches in the network
  • Elimination of recurring costs associated with a fabric of Ethernet switches in the network
  • Lower installation (CapEx) costs for a new or upgraded network (min 200 users)
  • Lower network energy (OpEx) costs
  • Less network infrastructure
  • You can reclaim wiring closet (IDF) real estate
  • Large bundles of copper cable are replaced with small single mode optical fiber cable
  • PON provides increased distance between data center and desktop (>20 kilometers)
  • Network maintenance is easier and less expensive

 

Conclusion

According to the above article, you may have a understanding of the passive optical network.A PON network eliminates the need for switches and a wiring closet, which means fewer points of failure. Fiber-Mart manufactures and offers customized services. any question pls welcome to visit www.fiber-mart.com or contact us.E-mail: service@fiber-mart.com

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