PON technology
PON (Passive Optical Network)— technology of passive optical networks.
One of the main challenges facing modern telecommunications access networks is the so-called "last mile" problem, providing as much bandwidth as possible to individual and corporate subscribers at minimal cost.
The essence of PON technology is that between the transceiver module of the central node OLT (Opterminal line) and remote subscriber nodes ONT (Optical network terminal) a completely passive optical network with a tree topology is created. Passive optical splitters (splitters) are placed in the intermediate nodes of the tree - compact devices that do not require power and maintenance. One transceiver module OLT allows you to transmit information to a plurality of ONT subscriber devices. The number of ONTs connected to one OLT can be as large as the power budget and the maximum speed of the transceiver equipment allow.
Rice. 1. PON network architecture
To transmit the forward and reverse channels, one optical fiber is used, the bandwidth of which is dynamically distributed between subscribers, or two fibers in case of redundancy. Downstream from the central node to subscribers is at a wavelength of 1490 nm and 1550 nm for video. Upstreams (upstream) from subscribers are at a wavelength of 1310 nm using the Protocol multiple access with time division (TDMA).
To build a PON, a point-to-multipoint topology is used, and the network itself has a tree structure. Each fiber segment connects to a single transceiver at the central site (as opposed to a point-to-point topology, which also results in significant savings in equipment cost. One fiber segment PON networks can cover up to 32 subscriber nodes within a radius of up to 20 km for EPON / BPON technologies and up to 128 nodes within a radius of up to 60 km for GPON technology. Each subscriber node is designed for an ordinary residential building or office building and in turn can cover hundreds of subscribers. All subscriber nodes are terminal, and the shutdown or failure of one or several subscriber nodes does not affect the operation of the others.
The central PON node can have ATM, SDH (STM-1), Gigabit Ethernet network interfaces for connecting to backbone networks. The subscriber node can provide service interfaces 10/100Base-TX, FXS (2, 4, 8 and 16 ports for connecting analog SLTs), E1, digital video, ATM (E3, DS3, STM-1c).
Fig.2. Technology Comparison
PON network testing
When testing a PON network, an operator usually has two main concerns:
- Real attenuation in optical line between the central node and the subscriber device (operating or preparing for connection).
- The location of the problem area, if the actual attenuation in the line turned out to be higher than expected (calculated or reference).
To answer the first question, it is enough to make simple measurements using an optical tester. The second question is more complex and requires the use of an optical reflectometer (OTDR), as well as some experience in reflectogram interpretation.
As a rule, it is desirable that all necessary measurements can be carried out on a working PON network without disconnecting subscribers (except possibly the one under test). Such testing is carried out at a non-operating wavelength using additional devices (DWDM wave multiplexers, filters) so that the radiation of the measuring equipment does not interfere with the useful signal. As already mentioned, in the PON network for the direct channel (from the center to subscribers) the wavelength is 1490 or 1550 nm (for video), for the reverse - 1310 nm. For PON network testing, a wavelength of 1625 nm is commonly used.
The radiation of the measuring equipment (tester, reflectometer) is injected into the fiber immediately after the OLT using a wave multiplexer (DWDM). This radiation can cause interference on the optical receiver of the subscriber device, so a filter must be installed in front of each ONT subscriber device. In order to be able to carry out testing without disconnecting the network, the wave multiplexer and filters must be permanently connected to the optical path, (see Fig. 3).
Rice. 3. Scheme of connecting the wave multiplexer and filters to PON
An optical tester at 1625 nm is used to measure the attenuation in the optical link between the OLT and ONT. The tester's transmitter is connected to the free end of the wave multiplexer on the OLT. The tester's receiver is connected to the free end of the fiber before the filter, (see Fig. 4).
Rice. 4. Attenuation measurement with disconnection of the subscriber device
It is possible to measure the attenuation without disconnecting the subscriber device. To do this, it is necessary to use not a filter on the ONT, but a wave multiplexer, as on the central node (see Fig. 5).
Rice. 5. Attenuation measurement without disconnecting the subscriber device
The attenuation at a wavelength of 1625 nm is slightly higher than at 1550 and 1490 nm (by 10% on average). Therefore, attenuation testing at 1625 nm provides an upper estimate for attenuation at operating wavelengths. If this estimate is within the allowable budget (23 dB), then the attenuation at operating wavelengths certainly satisfies the budget requirements. If the attenuation at a wavelength of 1625 nm exceeds the allowable value, then in order to accurately determine the attenuation at operating wavelengths, it is necessary to recalculate based on the passport of the optical cable.
Measurement in PON using an optical tester allows you to get the real attenuation value in the section from OLT to ONT, but does not answer the question of where the problem area is if this attenuation turned out to be higher than expected (calculated or reference). To localize the problem area, a more complex device is used - an optical reflectometer (OTDR).
A scatterometer with a 1625 nm test module is connected to the free end of the wave multiplexer on the OLT, (see Fig. 6). The reflectometer radiation propagates along the PON tree and, due to reflection on obstacles and backscattering in the optical fiber, partially returns to the input of the reflectometer. Thus, the reflectogram of the PON tree is taken - a graph of attenuation in the line depending on the distance. Each attenuation peak or step in this graph corresponds to a specific network element or fiber event.
Rice. 6. Retrieval of the reflectogram of the PON tree
The technique for testing the PON network using a reflectometer is as follows. After each change in the network topology (connection of a new subscriber, replacement of a splitter, etc.), a reference (reference) reflectogram is taken, corresponding to the normal state of the network. If problems are detected in the network (for example, if the attenuation measured by the optical tester turned out to be higher than the calculated one), a new reflectogram is taken, which is compared with the reference one. New events on the trace locate the location of the problem area, (see Fig. 7).
Rice. 7. Analysis of new events on the reflectogram.
With the OTDR, you can monitor the PON network and detect fiber degradation before problems occur. To do this, it is necessary to regularly (for example, once a week) take a network trace and compare it with a reference trace. If any deviations and especially new events appear on the reflectogram, it is necessary to analyze them possible reasons and, if necessary, take appropriate preventive measures.
In economically developed countries, this technology has long been widespread. It began to develop intensively from the distant 90s.
The rapid adoption of the technology in Europe, as well as in Japan and the United States, has been greatly influenced by its high speed network transmission, reliability and low operating costs.
Today, in the cities of the Russian Federation, some providers also provide their subscribers with access to communication services through this progressive technology, thanks to which only one cable makes it possible to simultaneously use telephony, interactive television and high-speed Internet.
Technology Description
Answering the question: “What is GPON?”, Firstly, its capabilities should be noted.
The technology provides several services simultaneously via one communication channel, while ensuring a high speed of information exchange, which is especially important during the broadcast of sound and video.
Secondly, it would be advisable to familiarize yourself with the decoding of some abbreviations. The operation of a passive optical network, or "PON" (Passive Optical Network) for short, is to provide multi-access over a single fiber optic wire through the multiplexing of the receive-transmit paths.
PON technologies quickly improved and the Ethernet PON standard was developed to provide high-speed information transfer, and soon its upgraded version Gigabit EPON was released, which is now inferior only to gigabyte passive optical systems, that is, briefly “GPON”.
The decoding of this abbreviation in English language looks like this: Gigabit capable Passive Optical Network. 
Pros and cons
The technology involves the use of a light channel to transmit information via fiber optics.
It is this circumstance that imposes some disadvantages, although the advantages of the technology more than cover the accompanying disadvantages.
GPON provides for the laying of fiber directly into the subscriber's home and allows you to reach the speed of work on the world wide web up to 2.5 kbps.
To connect, the client needs to install an optical terminal or, in the original language, "Optical Network Terminal" - abbreviated as ONT. It is usually provided by the provider itself.
The terminal, or as it is used to be called in our country, the modem-ONT is already equipped with a Wi-Fi module, so there is no need to stretch the cords further from the device around the apartment.
To transmit a light pulse through a special cable, it does not consume as much energy as to ensure the reception and transmission of data over a metal conductor.
It is quite difficult for attackers to intercept such a signal, and fiber optic cable is also not afraid of electromagnetic interference. This determines the reliability and quality of communication.
The GPON network allows you to provide the subscriber with high-quality telephone connection using an IP phone, several numbers on a single line, and also, if the client wishes, it is possible to save the number after changing the place of residence.
Of the main advantages, it should also be noted the high throughput and the simultaneous use of various services.
The word "passive" is not in vain used in the name of the technology. It implies operation without the use of intermediate equipment, that is, there are no switches and similar equipment on the line between the client and the station.
As you know, any device has a habit of breaking down and needs to be serviced periodically, not to mention the fact that it does not work without a power supply. These factors add up to the economic benefits of GPON.
Since there is no fiber Electric Energy, there is no danger for the subscriber to suffer from a current discharge, and also such a cable is absolutely indifferent to high humidity.
The user should be well aware of all the shortcomings of the technology. This will help him avoid unnecessary cash expenses and preserve personal psychological health, not only your own, but also of specialists from service center provider.
Optical fiber is very easy to damage by mechanical impact on it. Even minor local bends often lead to damage, therefore, in order to avoid such risks, it is recommended to install the modem as close as possible from the entry point to the gpon house.
Often, small cable crushing, for example, with a chair leg, led to a decrease in its throughput. Typically, devices are mounted right at the entrance to the living space.
The wire must be located out of reach of pets, as cats and especially dogs feel it is their primary duty to test the strength of the cable with their teeth.
Restoring a fiber or replacing it for a subscriber is an expensive procedure, and it is better to immediately stop all non-warranty cases in the bud.
The main disadvantage, which is indicated by engineers, relates to the economic issue of payback for the introduction of technology. The infrastructure of the appropriate equipment and cables pays off only if there are a large number of subscribers and the payback period is relatively long.
This leads to the introduction of GPON only in cities, and residents far from them have to continue to be content with the Internet using outdated transmission technology over copper wires, fortunately, telephone cables in Russia are laid almost everywhere.
GPON equipment
The equipment for connection is provided by the provider, for example, you can make an application to Rostelecom in many cities of the Russian Federation. Sometimes equipment is rented or purchased by the user with fiber optic connectivity.
Therefore, the nuances must first be clarified with the communication service provider. It will also help in the future to properly configure the connected subscriber devices (PC, TV, telephone, mobile gadgets, etc.).
A cable is laid in the client's house and installed gpon optical terminal, next to which there is an electrical outlet from which power will be supplied to the device.
This terminal is designed to convert the fiber optic interface to an Ethernet interface.
Terminal models have different functionality, so before installation, you should clarify the possibility of connecting devices via Wi-Fi channel, IPTV, telephony, etc.
How to connect?
Due to lack of awareness, users are often extremely surprised to learn that the connection procedure includes drilling a wall in an apartment (otherwise how to insert a cable into a room), installing equipment (technically ignorant subscribers ask a perplexed question: “Why is there a device and cabling in the house?” do you need wireless internet?” etc.).
In addition, if the client needs interactive TV, then a special set-top box must be connected. Some need to make it work landline phone and connect a security fire alarm, video surveillance.
Therefore, the instruction for resolving the issue of how to connect depends on each specific case and the wishes of the person who has entered into an agreement with the provider.
During the connection, the optical fiber from the customer's home to distribution equipment is laid in reliable boxes that protect fragile material. In the connection diagram, this is a key point.
Connection of ONT with PC (if Internet service is available) and ONT with IPTV set-top box (if interactive TV service is connected) is performed via twisted pair cable.
The only thing that is required from a person who decides to connect GPON is to choose a provider and, by visiting his website or by phone, contact him.
Next, clarify the possibility of connection by providing the exact address and, if the outcome is positive, apply for connection. Further, having concluded an agreement with the provider, meet the installers at home, who, having installed the terminal, will set up communication services.
Then, if the subscriber wants to change services, they are adjusted remotely. 
Internet GPON
GPON technology is able to provide the user with Internet at a speed of up to 500 Mpbs, and this is with the simultaneous operation of several devices. Not on the network negative impact radio and magnetic interference.
Internet via Gigabit PON is reliable, since there is no active equipment on the Client-PBX line, which means that there is simply nothing to fail.
The throughput value reaches 1 Gpbs, however, routers that do not have enough power to transfer such a volume of virtual data often become a weak link in the chain.
Of course, the characteristics in numbers may not tell people anything, but even a value of 0.5 Gpbs is more than enough for the average user, for example, at such a speed, you can download a full-length movie in HD quality in a few minutes, and such files weigh about seven gigabytes .
Tariffs
The Russian Federation is a large country stretching for thousands of kilometers from west to east. It should be noted that the farther to the east, the more expensive the tariffs. It is more profitable to connect the services of Russian providers offering GPON tariffs in cities in the western part of the country, for example, in Moscow.
But the most expensive fiber-optic communication will cost citizens living on Far East. It is recommended to find out the latest prices on the official resource of the communication service provider.
A popular provider in the Russian Federation that provides Internet via fiber is RTK.
For example, for residents of cities in the central part of the country, on average, the provider will need to pay monthly services in the amount of 350 rubles, but this is at a minimum access speed. The billing by the provider is subject to the generally accepted formula: “The more the subscriber pays money per month, the cheaper each megabit costs”.
The billing already includes the cost of equipment provided to the client by the company. Given this fact, the prices of tariffs for users are justified.
So MGTS provides equipment to customers free of charge. The initial setup by the company's specialists is free of charge. 
Conclusion
The technology is attractive and versatile, however, in the absence of a sufficient customer base, it is unprofitable, therefore, it is used only in apartment buildings large cities.
If the user lives in the private sector, remote from optical communications, then it is not profitable for the provider to pull the infrastructure to him.
Of course, only if you do not agree with all the residents of the suburban village and connect to high-speed Internet collectively.
This is due to the requirements of new services and "heavy" applications that can fully function only with a PON connection from Rostelecom. That is why it was necessary to introduce fiber optic technologies that meet the requirements of high-speed Internet.
This article contains several items:
- What is PON technology
- Features of PON Internet
- Connection equipment
- Setting up modems
PON technology from Rostelecom
The most important advantage of this technology compared to other types of connection is the high data transfer and, as a result, the responsiveness of networks. Therefore, a PON connection is optimal for connecting large co-companies to the Internet.
Currently, Internet speed requirements reach 100 Mbps, and will approach 1 Gbps in the near future. Only optical cables can support such high performance. This is especially true for large distances, which, of course, exist between the provider and the user.
For service providers, FTTH (Fiber to the Home) bandwidth is already available, which is routed to the home. Thus, new buildings will serve as the basis of access networks and will be able to function for many years. The implementation of FTTH access networks is far from being a cheap process, which requires not only labor-intensive construction works but also significant financial costs.
However, the development of Wavelength Division Division (WDM) technology, which uses a single fiber for incoming and outgoing traffic, is to a large extent improved the situation. The first of the FTTH networks have already moved to a newer standard, where a single fiber is connected to a passive optical splitter, which in turn distributes the signal to several subscribers.
It was this standard that began to be called the PON technology, which Rostelecom is now actively using. With this technology, the network can support 1:64 signal splitting from a single fiber. In addition, Rostelecom's PON technologies allow subscribers to use without the use of IP set-top boxes.
Advantages of the Internet using PON technology from Rostelecom
The most significant advantage of PON Internet from Rostelecom is that with the help of inexpensive optical splitters, a common fiber provides a network for many users. But it should be remembered that such splitters maintain network responsiveness with up to 64 users. Thus, this technology is of interest not only to subscribers, but also to service providers who want to replace somewhat outdated copper networks.
Features of PON networks, which can also be called pluses, are:
- absence of electromagnetic interference, since there is no need to use active equipment directly in the access network;
- reduction of fiber and equipment in the central office.
Rostelecom's PON equipment provides greater throughput and supports dual distribution ratio. This means that with a 64-lane allocation, each user will get a fairly large connection bandwidth, about 35 Mbps. If the provider uses lower distribution factors, for example, 16 or 32, subscribers will receive even more bandwidth. Due to the efficient use of the bandwidth of the PON standard, subscribers are provided with a high data transfer rate. In addition, this technology makes it possible to use not only high speed internet, but also multi-services such as video, voice, data.
Which modems are suitable for connecting PON from Rostelecom
GPON technology is an industry-wide interchangeable standard. This indicates that PON modems of any manufacturer will work correctly with devices such as ONT.
This, in turn, affects the reduction in the cost of equipment and enables providers to offer subscribers the most favorable tariffs for services. Also, it is important to note that the updated technology based on XGPON standards increases network performance up to 10 Gbps, while maintaining backward compatibility with already deployed networks.
How to set up the equipment
As a rule, PON equipment from Rostelecom does not need to be carefully configured, since all the necessary parameters have already been entered by the provider. But in some models WiFi router with PON technology, configurations will need to be adjusted wireless network and set connection parameters. These parameters include the login and password of a PPPoE user type, which Rostelecom provides to the subscriber when concluding an agreement.
If, after correctly entering all the necessary parameters, the PON indicator on the equipment lights up red, we recommend that you contact the service with this problem. technical support Rostelecom clients.
If you have any questions about this technology, we recommend watching this video.
Rostelecom and PON technology in Vologda video
The speed required to ensure the smooth operation of applications must be 1Gbps or higher. Providers are soon expected to develop optical access infrastructure to provide a wide range of services. The latest trend right now is passive optical network technology, i.e. GPON.
This abbreviation stands for Gigabit Passive Optical Network or Gigabit Passive Optical Network. GPON is a kind of PON technology, so let's first explain what PON is.
The main office has an OLT (Optical line terminal) module, while subscribers have an ONT (Optical network terminal). The nodes are equipped with splitters that do not require maintenance. It turns out that the main module has the ability to send data to a large number of subscribers. The number of subscribers who connected to the transceiver module depends only on the power and top speed equipment.
Passive optical networks have many upgraded versions that cover a variety of tasks. Some are effective for mass use, others for corporations.
Now a little history. In 1980, British Telecom began developing PON technology. Later, tests were carried out, and the world's leading specialists in the field of communication began to develop a standard for PON technology. In 1998, the ATM PON (APON) specification was adopted and the construction of passive fiber networks began in America and Japan.
Every year PON technology develops. The first APON specification allowed data to be transferred bidirectionally at a rate of 155 Mbps. Later, a variety of PON appeared - BPON with speeds up to 622 Mb / s with access via Ethernet. In 2001, the development of EPON (Ethernet PON) based on MPCP (Point-to-Multipoint Control Protocol) started.
At the moment, APON, BPON, EPON technologies are outdated and should not be considered in detail. But the GPON (Gigabit PON) technology is by far the most promising. The standard was adopted in 2003. GPON provides bi-directional, high-speed transmission up to 2.5 Gbps. This network is highly reliable due to passive optical splitters in intermediate nodes. The technology saves fiber optics, since up to 128 subscribers can be connected on one cable and located at a distance of tens of kilometers. The level of network security is high due to encryption technologies and the isolation of each service. GPON allows you to choose at what speed you want to transfer data: the same or different. Even if we consider the most unfortunate traffic distribution, the bandwidth utilization is 93%, which is much higher than in previous versions of the technology. All of the above pluses of technology can be countered by only one minus - its increased complexity.
What is the future of passive optical networks? User needs are growing and soon existing networks will not be able to meet them, so manufacturers are developing the next generation of NG-PON passive optical networks. Developers are trying to increase
GPON - Gigabit-capable Passive Optical Networks - Gigabit passive optical network.
For the first time about technology pon started talking in the 1990s when several leading European operators, including British Telecom and France Telecom, formed a consortium to develop single fiber multiple access technology. Thus, the technology distinctive feature which is the use of passive optical splitters (splitters) for combining traffic that do not require power and maintenance.To date GPON(PON) allows you to run a fiber optic cable to the apartment and provide a bandwidth of up to 1 Gb / s, which is 100 times higher than the capabilities ADSL access. Technology Implementation GPON(PON) ensures the provision of Triple-Play services on one fiber: Internet, VoIP, IPTV; and the high bit rate allows you to view multiple channels HDTV simultaneously. The new network allows local phone calls by technology IP telephony.
How to connect GPON MGTS in Moscow and Moscow region?
To do this, you just need to leave online application to connect, fill out the form and select the GPON service and send a request, the MGTS operator will call you back in the near future.
What does GPON technology provide?
High-speed Internet at speeds up to 1 Gb / s. The latest interactive IP-TV, which will provide an opportunity not only to watch more than 60 satellite and terrestrial digital television channels, including 10 high-definition HDTV channels, but also to use interactive services: order a movie recording and watch it after the broadcast, watch a TV show, the broadcast of which has already taken place, order a film from the video library High-quality communication with the ability to connect both a regular and IP-telephone with an extended set of functions, an unlimited number of numbers on one line and keeping the number when moving. Using IP-telephony services, you can significantly save on calls to other cities.
Unlike other operators that provide an optical channel to the building, GPON(PON) technology involves a fiber optic channel directly to the subscriber's apartment. This allows not only to significantly improve the quality of signal transmission (data, video, voice), but also to increase the data transfer rate by dozens of times, to freely transmit several high-definition TV channels simultaneously over the network.
Benefits of GPON (PON)
Reliability- protected from unauthorized access, the fiber optic cable is resistant to electromagnetic influences;Speed- optical fiber has a huge bandwidth, so the speed and quality of transmission compares favorably with other technologies (both wired and wireless);
Additional services-possibility in the future, based on the technology used, connect the following services - remote video surveillance of any object (home, office); the possibility of uninterrupted operation of security systems;
Complexity - PON technology allows you to connect to 1 fiber 3 Internet services, digital television, telephone ;
Flexibility- GPON(PON) technology allows you to configure the equipment in accordance with the individual characteristics of the subscriber and provide exactly the level of service that the subscriber needs;
improvisation- allows you to use the most modern technologies data transmission;
Environmental friendliness- does not have e / magnetic radiation;
Perspective of use- with the constant growth of the requirements of the content transmitted over the network to the speed of information transfer, the technology solves this problem for several years to come.
Distinctive qualities of GPON for subscribers:
- a new standard for Internet access speeds - from 10 Mbps. up to 1 Gb/s;
- high quality connections without breaks and interference!
GPON technology provides for the laying of a fiber optic cable directly into the apartment, thereby guaranteeing a constant speed of Internet access.
The subscriber is provided with the entire resource of the optical cable, which is brought directly to his apartment, in contrast to home network operators, where the channel is allocated to the house and, accordingly, is equally divided between the connected users.
This connection method guarantees high-quality services, stable high speeds.
To connect to GPON technology, a subscriber is provided with a free modem - ONT (Optical Network Terminal), thanks to which all services are connected remotely and in one device, and it also has built-in Wi-Fi, through which you can work wirelessly from any device on the Internet .
New technology means new opportunities
At the time of connection, all clients have access to a multi-service package - the optimal set of services for the home, consisting of:
- Internet;
- digital home telephony;
- high-definition television (with HD support).
The technology provides for the constant replenishment of a number of additional services:
- telemetry;
- security and fire alarm.
GPON tariffs for MGTS subscribers
Explanation of abbreviations |
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