FTT technology. FTTx from Rostelecom: technology features

In our reviews, we have already managed to consider dozens and hundreds of tariffs for Internet access. We covered almost all Russian regions and large cities. We talked about access technologies, but did not cover this topic 100%. In this review, we correct the situation by talking about FTTx. Rostelecom's FTTx technology is high speed connection to the Internet via optical fiber. Let's see how it works and what opportunities it promises to subscribers.

Legacy technologies

Rostelecom has been promoting ADSL technology for a long time. After a slow Dial-Up with a busy voice line, ADSL was a breath of fresh air. The technology allowed and still allows you to get speeds up to 24 Mbps. But this is only for downloads - the return from ADSL is weak and does not exceed 0.3 Mbps. Although when using some standards, indicators up to 3.5 Mbps are achieved. In practice, this is almost invisible.

ADSL requires the simplest telephone line with a resistance of not more than 900 ohms. That is, the length of the conductors plays a decisive role. The line must be good, with a resistance between the cores of at least 100 MΩ. There are also requirements for the capacity of the entire telephone loop. Such ideal lines exist, but they are few. That's why maximum speed will be only for those who live in the immediate vicinity of the telephone exchange. A distance of 5-6 km for a telephone line with ADSL is considered the limit, the access speed drops to 2-3 Mbps.

What has changed with the advent of optics

FTTB technology and FTTx technology are almost the same thing. The Latin letter B stands for Building (building). Full decoding of the abbreviation FTTB - Fiber-To-The-Building. That is, an optical cable to the building. In the case of FTTx, it is an optical cable to point X. Where X can be a building, an entrance, a local communication center.

Optical cable is an ideal means of communication. Losses in it are minimal, the speed is up to several Gbit / s. Today, there are technologies that allow fiber optics to be installed in every home. But the result is a high connection cost. The situation was corrected by technology from Rostelecom GPON - passive optics in each apartment. It is capable of providing speeds up to 1 Gbps for each subscriber.

Let's get back to Rostelecom FTTB (aka FTTx). The scheme for building a network in this case is as follows:

A high-speed optical cable reaches the house communication center installed in the basement or in the attic (upper floor).
A twisted pair cable is being laid along the entrance - it is possible to bring it into each apartment.
The twisted pair is connected directly to the subscriber equipment - this is a computer or a router.

If the ports on the home communication node are gigabit, each subscriber will be able to receive speeds up to 1 Gbps. In practice, the numbers are many times less, Rostelecom's tariffs do not give more than 200-250 Mbps. The final values depend on the connection region.

There is information that for some subscribers Rostelecom can offer individual tariffs with speeds up to 1 Gb / s - this point needs to be clarified at the offices.

In fact, the same 100 Mbps on FTTx is enough for the eyes. Movies are downloaded in 15-20 minutes - during this time you can warm up tea or order pizza. Smaller files are downloaded in seconds. The technology does not require any modem. Rostelecom specialists will connect the cable to network card your PC, and you're done - you have broadband internet at home. If the Internet is needed on several devices, use a router (router).

Setting up the connection

Setting up a Rostelecom FTTx router consists in creating a PPPoE connection. The subscriber is issued a card with a login and password - these data will be required for authorization. Next, go to the router settings, create a PPPoE connection, give it an arbitrary name, enter a username and password. We reboot the router, watch the Internet indicator - it should light up and blink. Now we connect home devices to the router and enjoy network access.

FTTx technology involves connecting to the home data network (CGL) via twisted pair. This is such a copper cable for eight cores. You can run it behind skirting boards or under the ceiling. We recommend that you immediately purchase at least the simplest router. Suitable model is TP-LINK TL-WR840N. Its cost is from 900 rubles. The device connects to the SPD of Rostelecom via FTTx and organizes a wireless access point within a radius of 10-15 meters - just within the apartment for 2-3 rooms.

In the private sector, Rostelecom's optics can go directly into the house, without any house communication centers. It's not called FTTx, it's called FTTB. The speeds are about the same. Instead of a communication node, a media converter is installed, and a router is connected to it.

14.6. Access technologies on optical communication lines

14.6.1. Technologies of the FTTx group

FTTx Technology Group (Fiber To The x - optical fiber up to ...)is designed to be used in conjunction with ADSL and VDSL technologies and allows more efficient use of the bandwidth of these technologies due to the reduction in the length of copper-cable communication lines. There are several options for implementing FTTx, of which the main ones can be distinguished:

FTTH - Fiber To The Home (bringing fiber to the apartment);

FTTB - Fiber To The Building (bringing fiber to the building).

Options, in fact, duplicating FTTH and FTTB with minor changes:

FTTN (Fiber to the Node) - fiber to the network node;

FTTO - Fiber To The Office (bringing fiber to the office);

FTTC - Fiber To The Curb (bringing the fiber to the cable closet);

FTTCab - Fiber To The Cabinet (similar to FTTC);

FTTR - Fiber To The Remote (bringing the fiber to a remote module, hub);

FTTOpt - Fiber To The Optimum (bringing the fiber to the optimal point);

FTTP - Fiber To The Premises (bringing the fiber to the client's point of presence).

Separately, it should be noted the concept

FITB (Fiber In The Building) is the organization of a distribution network inside a building.

The above technologies differ mainly in how close the optical cable comes to the user terminal (Figure 14.29).

Figure 14.29 - FTTx optical access technologies

On the this moment there is a growing interest in the deployment of optical access networks with cabling to the building (FTTB), as well as directly to the subscriber (FTTH). To a large extent, this situation is explained by the constant growth of requirements for bandwidth communication channels, since there is now a boom in the development of "heavy" Internet applications, including online video, online games and other services.

At the same time, the planned set of services and the bandwidth required to provide them have the most direct impact on the choice of FTTx technology. Therefore, the higher the access speed and the larger the set of services provided to the subscriber, the closer the optical fiber should come to the subscriber terminal, i.e. you need to use FTTH technologies. In the case where the priority is to preserve the existing network infrastructure and equipment, FTTB will be the best choice.

If we talk about today's realities, the FTTB architecture prevails in new buildings and large telecom operators, while FTTH is in demand in the new low-rise construction(for example, in cottage townships in the vicinity of large cities).

Consider the features of the implementation and application of the most common technologies.

FTTN technology It is mainly used as a budget and quickly implemented solution where there is a distribution "copper" infrastructure and laying optics is unprofitable. Everyone knows the difficulties associated with this solution: the low quality of the services provided, due to the specific problems of copper cables lying in the sewer, a significant limitation on the speed and number of connections in one cable.

FTTC technology- This is an improved version of FTTN, devoid of some of its shortcomings. The FTTC architecture is primarily intended for operators already using xDSL or PON technologies and cable television operators. The implementation of the FTTC architecture will allow them to increase the number of users served and the bandwidth allocated to each of them at a lower cost. In Russia, this type of connection is often used by small Ethernet network operators. This is due to the lower cost of copper solutions and the fact that the installation of an optical cable requires a highly qualified performer.

FTTB Technologysuggests bringing the fiber to the building, and is most widely used, since in the construction of FTTx networks based on Ethernet, this is often the only technically possible scheme for building a network. In addition, in terms of cost structure for building an Ethernet network, the difference between the FTTC and FTTB options is relatively small. Also, we should not forget that the operating costs of operating the FTTB network are lower, and the throughput is higher.

FTTB technology is advisable to use in the case of network deployment in apartment buildings and business centers. Russian telecom operators are deploying FTTB networks so far only in major cities, but in the future it is planned to use this technology everywhere. In FTTB, there is no need to run expensive optical cable with a large number of fibers, as with FTTH.

In the case of FTTB, optical fiber is brought into the house, usually in the basement or attic, and connected to the ONU (Optical Network Unit). On the side of the telecom operator, an optical line terminal OLT (Optical Line Terminal) is installed. The OLT is the primary device and determines the traffic exchange parameters (for example, signal reception/transmission time intervals) with the ONU (or ONT, in the case of FTTH) subscriber devices. Further distribution of the network around the house occurs over the "twisted pair" (Fig. 14.30).

FTTH technology is the most expensive, but at the same time the most promising, among all types of FTTx access. FTTH involves bringing optical fiber to the user's apartment or private home. In this case, the optical fiber is brought into the house, usually in the basement or attic (which is more economically feasible) and connected to the ONU (Optical Network Unit). On the side of the telecom operator, an optical line terminal OLT (Optical Line Terminal) is installed. The OLT is the primary device and determines the traffic exchange parameters (for example, signal reception/transmission time intervals) with the ONU (or ONT, in the case of FTTH) subscriber devices. Further distribution of the network around the house occurs over the "twisted pair" (Fig. 14.31).

At first glance, building an FTTH network is a very time-consuming and expensive process, but experience suggests that the main cost of deploying an FTTH network is construction work, and the cost of the fiber optic cable itself is a relatively small part. This means that, if necessary, construction works the amount of fiber optic cable to be laid is no longer of great importance.

Moreover, although life cycle FTTH network and its electronic components is several years, fiber optic cable and optical distribution network have a longer service life (at least 30 years).

Deployed FTTH network architectures can be divided into three main categories:

- "Ring" of Ethernet switches.

- "Star" of Ethernet switches.

- "Tree" using PON passive optical network technologies.

FTTB Internet connection technology is currently the most widespread in the world. In the early 2000s, it made a revolution in the provision of provider services and remains the most popular due to its simplicity and reliability. But such a connection has limitations and disadvantages, which must also be taken into account when connecting to the network.

What does FTTB mean?

Provision by an Internet provider using FTTB technology implies always a connection apartment building. On the English language the abbreviation stands for “Fiber to the building” - literally “Optical fiber to the house”. This is one of the variations on the use of FTTx technology, where "X" can mean both a large distribution hub of an entire area, and a separate end device, such as a home computer.

If FTTB is mentioned when concluding an agreement with a provider, this means that a fiber optic cable is being run to the house. Then it is connected to a distribution node in the basement or on the roof of the building, and copper twisted pairs are already laid to the apartments, which are connected directly to a computer or to a router, which allows distributing Internet access to several devices at once.

Attention! Externally, the connection will look like a normal cable from the entrance to the apartment without installing a modem. Just a cord and that's it.

What gives the use of FTTx?

This technology is used by all providers providing services in apartment buildings: Beeline, Rostelecom, MTS, Zelenaya Tochka and others. The main distinguishing feature that FTTB will use is always beautiful sentences:

speed up to 100 Mbps, allowing you to download movies in minutes and participate in online conferences and play over the network;
unlimited Internet, no restrictions on the amount of traffic;
the ability to connect digital television and IP-telephony through 1 cable.

All these opportunities have appeared precisely due to the use of optical fiber using FTTB technology as the basis for providing access to the network.

What was before?

The connection scheme using FTTB technology has become widespread for a reason. Those who used the Internet in the last millennium remember that access was limited and the speed was very low. In addition, a cord was connected through the telephone, which created additional restrictions.

These are all signs of using ADSL (“Asymmetric Digital Subscriber Line”). From a technical point of view, the difference was in the materials for the cord, through which the signals are transmitted. Previously, instead of optical fiber, copper was used for this purpose. it good stuff, but it has a few significant limitations:

Signal transfer rate. Unlike today's fiber optic scheme, ADSL only provided traffic at speeds up to 24 Mbps. But this is in ideal conditions, but in fact - several times lower.
Asymmetric transmission of information. 24 Mbps is for downloading files. And downloading information to the network was 8 times slower.
Interference. Bad weather, radiation from equipment or power lines constantly led to interruptions in communication.
Single thread. It was impossible to use the phone and the Internet at the same time. Nobody thought about the possibility of watching TV shows.

An optical cable is free from these disadvantages and, moreover, is cheaper to manufacture. Therefore, he gradually supplanted his predecessor.

What are the limitations of fiber

Considering how different ADSL technologies and FTTB, it is not surprising that the move away from copper has provided more network access and has become the basis of growth for service provider firms.

But the current system also has several drawbacks that limit its distribution:

Price. It costs money to run fiber optic cable to the house and install a distribution node. Therefore, the private sector and areas remote from the city center, as well as villages, remain without wired Internet.
Speed. Fiber is capable of transmitting information at a rate of 1 Gb / s, but the distribution of twisted pair cables reduces it by a factor of 10.
Threads. Internet, TV and telephony are the limit of FTTB connection technology. It is no longer possible to connect other systems to one cord and a separate line must be drawn.

Urban dwellers rarely find themselves inconvenienced by the shortcomings of FTTB technology. And all the advantages of such a connection allow the existing scheme to successfully compete with other types of communication, including wireless.

What will change in the future

At the moment, large providers are already offering consumers new services that are provided not thanks to FTTB, but through PON (“passive fiber optic network”) technology. The fundamental difference between these schemes is only in the rejection of the copper twisted pair. This allows you to get rid of the distribution node and lead the fiber directly to a separate house or apartment.

Important! PON and GPON are the same. The letter “G” only emphasizes the ability of fiber to transmit information at a speed of 1 Gb / s to attract customers.

When comparing FTTB and GPON connectivity, the difference is not only high speed. There are other important advantages of a passive fiber optic network:

The presence of a modem. If now, to repair the unit, it is required to open the shield located in the stairwell or in the basement, then new scheme allows you to carry out all the necessary procedures without leaving your home, consulting by phone with the support service.
Possibility of point connection. PON provides a real opportunity to spend quite cheaply wired Internet in the private sector.
Multithreading. Many more systems can be connected to a passive fiber network at the same time.

But all the possibilities of GPON are not yet so in demand by customers, and 100 Mbit / s is quite enough for the average user. Therefore, in the coming years, providers will continue to use FTTB technology to serve the population.

FTTX Technologies

Many companies began to gradually move to the use of FTTx technology as the main one for providing services in the field of Internet access. Now it is no longer as difficult and expensive as it was a few years ago. That is why the corresponding product is actively promoted on the market.

The use of FTTx technology involves the use of fiber-optic solutions for building broadband networks. It is worth describing what is meant by this new concept. FTTx is a term that describes a general approach to the formation of a cable network infrastructure, in which optics reach a specific place, designated as "x", from the communication node, and then, directly to the subscribers, a copper cable is laid. It is quite possible to lay optics directly to the subscriber device. By and large, the use of FTTx technology involves only the physical layer. But this concept also hides a large number of network and link-level technologies. Broadband access allows a huge number of new services to be provided.

At the moment, the main driver of the FTTx market is the massive demand for broadband access, and it is very difficult to provide if only ADSL is used. Optical solutions have become more and more actively implemented in large cities, and there is a clear trend towards the merger of small operators with larger ones that operate on a federal scale. FTTx technologies are very actively used in settlements where the infrastructure was originally built on the basis of an optical path.

The development of the FTTx market in the Russian territory depends not only on the demand for high-quality content, but also on the number of large construction projects, as well as increased competition among broadband access service providers. Through dynamic construction apartment buildings laying FTTx networks is becoming very fast and economically justified, and competition is making the cost of accessing the Internet ever lower. A few years ago, the attention of operators was directed to the corporate consumer, and now ordinary subscribers are increasingly being considered.

FTTx technology (Rostelecom) includes several types of architectures: - FTTN (Fiber to the Node) - optical fiber reaches the network node;

FTTC (Fiber to the Curb) - fiber reaches a microdistrict, block or several houses;

FTTB (Fiber to the Building) - fiber reaches the building;

FTTH (Fiber to the Home) - fiber reaches the home.

The main difference is how close the optical cable comes to the user terminal. The first solutions to appear were FTTN and FTTC. The first solution is currently used exclusively as a quickly implemented and budget solution where there is a copper distribution infrastructure, and laying optics is simply unprofitable. The difficulties associated with such a solution are known to all: the low quality of the services provided, associated with the specific problems of copper cables located in the sewer, a significant limitation on the speed and number of connections in one cable. FTTC is an improved type of FTTN that does not have the disadvantages of the latter. In the case of FTTC, copper cables are laid only inside buildings, which means that they are not subject to destructive factors, and also do not have a long line length, the quality of the copper conductors used is also important. That is why it is possible to achieve greater speed in the area without fiber. This offer is valid when connecting using FTTx PON technology. This architecture is aimed at operators who are already actively using xDSL technology, as well as cable television operators. By implementing such an architecture, they can not only reduce costs, but also increase the number of connected users, as well as the bandwidth allocated to each of them. This type of connection in Russia is most often used by operators of small Ethernet networks, which is associated with the low cost of copper solutions, as well as the need for a highly qualified contractor to install an optical cable.

The intracity optical transport network is built according to the ring topology and organized on optical routers. A local network core is connected to it, which provides the necessary local communication services for subscribers, and subscriber access networks are also connected via an optical line or via an Ethernet cable, since the aggregation switch can be located on the PBX itself. Cables go from the aggregation switch to an optical cross, which is connected to the cable going to the houses. There are access switches in homes that have optical ports, most often with a data transfer rate of 1GE (Figure 13). This choice of data rate is due to the fact that at high speeds, dispersion strongly affects the length of the regeneration section.

Figure 13 FTTX Network Diagram

FTTX technology opens up great opportunities for broadband access. Cities are developing very quickly and there is competition between communication operators for each subscriber. And the one who provides better services at a reasonable price wins. But here comes an additional problem. In large cities, in order to provide users with high-quality broadband access, it is necessary to modernize the urban optical transport network, otherwise there will be no sense in the bandwidth of subscriber lines.

In townships, FTTX is a more appropriate technology. Weak attenuation in optical cables makes it possible to provide communication services to subscribers located at a great distance from the PBX (up to tens of kilometers). The use of copper-core cables in this case will not provide high speed and reliability, in addition, to install a line using DSL technology, it is necessary to build a cable duct, which leads to additional costs and loss of time. The advantage of FTTX technology is that an optical cable can be brought to the house through electric cables and this will not affect the bandwidth of the subscriber line in any way.

To save optical fibers and reliability, link aggregation (eng. Link aggregation, trunking) or IEEE 802.3ad is used - a technology for combining several physical channels into one logical one. This contributes not only to a significant increase in the throughput of the backbone channels switch-to-switch or switch-to-server, but also to increase their reliability. While the IEEE 802.3ad standard already exists, many companies still use proprietary or proprietary technologies for their products.

The main tasks of the aggregation layer are traffic monitoring and control with flow separation by service types and user requests. QoS multilayering and MPLS routing must be supported. The topology of the aggregation layer network usually provides for some redundancy, which allows redundant links through network reconfiguration. For this, equipment with increased fault tolerance is used that supports protection switching protocols. In small and medium carrier networks, the backbone layer and the aggregation layer are often presented together.

Other purposes of the aggregation level?-- connection to the operator network of various service departments(file or game servers, IPTV head stations) and organization of gateways to telephone networks. A properly designed aggregation layer allows you to create distributed services, which reduces the amount of intra-network traffic and increases the reliability of services.

The most capacious in terms of the number of devices level of the urban Ethernet network is the access level. It serves to connect subscribers, and the efficiency of the entire network of the telecom operator largely depends on it. With a large number of subscribers (for example, in the case of providing broadband access services individuals) at this level, intermediate aggregation is often used. The access layer infrastructure usually follows a star topology, but ring and mesh topologies are often used. The choice depends on the density and territorial distribution of subscribers.

Access equipment bears the main burden of implementing protection measures when connecting subscribers. These typically include the use of access control lists (ACLs) with binding to switch ports, static and dynamic assignment of a MAC address to a port, blocking unauthorized MAC addresses, 802.1x authorization, or binding an IP address to a specific MAC address. . At this level, support for quality of service mechanisms should be provided, which consists in traffic segmentation by priority queues.

In recent years, operators have required manufacturers to provide access equipment with multicasting capabilities. To do this, it implements the IGMP, DVMRP, MOSPF, PIM DM/SM protocols, etc. The choice of one or another protocol depends on the routing policy in the network of the telecom operator and on the topology of such a network.

A good tool for implementing a flexible tariff policy is the bandwidth control of the subscriber port, which to a certain extent allows predicting the load of channels at the backbone level and traffic aggregation. If it is planned to provide services to corporate clients, access equipment must support QinQ layer 2, VPLS (Virtual Private LAN Service), E-Line and E-LAN technologies in accordance with the Metro Ethernet Forum specifications.

In the access network, it is desirable to use equipment with good remote control and diagnostic capabilities. This reduces the load on the technical and service support services of a distributed operator network. The possibility of increasing the subscriber capacity of access nodes is also important, for example, due to the stacking of switches. Now the vast majority of network subscribers are connected via copper lines, for which the 10/100 Base-T interface is used.

Using several Ethernet adapters in parallel looks like this. Let's say there are two Ethernet adapters: eth0 and eth1. They can be combined into an eth3 pseudo-Ethernet adapter. The system recognizes these aggregated adapters as one. All aggregated adapters are configured with the same MAC address, so they are treated as a single adapter by remote servers. eth3 can be configured to a single IP address like any Ethernet adapter. Because of this, programs refer to it as to the most common adapter, the speed of which is twice as high.

In most cases, in cities with a large population, infill development is being carried out. For wireline operators, this causes certain difficulties. Cables have already been laid in many areas of the city. Laying new optical cables is not always cost-effective, and in some cases simply impossible. It becomes relevant to use optical cables laid ten or more years ago in an existing cable duct for digitalization telephone networks communication, it is more economically justified, since it is only necessary to replace the network equipment. To provide communication services in residential apartment buildings, FTTB technology is used, since it is more rational use finance (twisted-pair cable is cheaper and not afraid of bends), the user's terminal equipment using twisted-pair is much cheaper. When using twisted pair, there is a length limit of one hundred meters. Inside a residential building, this length is usually not exceeded by half.

In the equipment already in use, the two-fiber (Figure 14) mode is mainly used to link the aggregation switch and the access switch.

Figure 14 Scheme of a two-fiber optical line between an aggregation switch and an access switch.

This method of dual-fiber mode in modern conditions is not rational.

To save optical fibers, telecom operators introduce a single-fiber mode using WDM SFP optical modules or selective optical Y-shaped splitters (Fig. 15). The cost of WDM SFP modules is much higher than usual and there is also a significant difference in cost between SFP modules with different wavelengths. An SFP module operating at a wavelength of 1310 nm is almost two times cheaper than one operating at a wavelength of 1550 nm. Selective Y-splitters save money on WDM SFP modules.

For greater cost savings and ease of connection, non-selective Y-splitters can be used.

Figure 15 Transmission line in single fiber mode between access switch and aggregation switch.

What it is?

The use of FTTx technology involves the use of fiber-optic solutions for building broadband networks. It is worth describing what is meant by this new concept.

FTTx is a term that describes a general approach to the formation of a cable in which optics reach a specific place, designated as "x", and then, directly to subscribers, a copper cable is laid. It is quite possible to lay optics directly to the subscriber device. By and large, the use of FTTx technology involves only the physical layer. But under this concept there is a large number and a channel level. Broadband access allows a huge number of new services to be provided.

Interest in such networks

Market prospects

The development of the FTTx market in the Russian territory depends not only on the demand for high-quality content, but also on the number of large construction projects, as well as increased competition among broadband access service providers. Thanks to the dynamic construction of apartment buildings, the installation of FTTx networks is becoming very fast and economically viable, and competition is making the cost of accessing the Internet ever lower. A few years ago, the attention of operators was directed to the corporate consumer, and now ordinary subscribers are increasingly being considered.

Construction feature

Until recently, FTTx technologies were used by operators that did not have their own old generation infrastructure, that is, they were made of copper, and this was due to the increased cost of forming structures from fiber optics. However, in the last few years, interest in new networks has been growing. Reasons for this include the expansion of services, the expansion of passive optical networks (PON) and the spread of Metro Ethernet, the reduction in the cost of fiber optic products, as well as the success of some operators in the field of building such networks.

New content types

FTTx connectivity is becoming more and more popular as modern users are increasingly interested in new types of video and graphics content. High Quality. The main catalyst for the adoption of fiber optic systems has been the growing interest in video services. The shift in the center of gravity from group broadcasting to individual broadcasting means an increase in subscribers' demand for dedicated broadcasting, which will soon reach up to 100 megabits per second per household.

Sales of LCD high-definition televisions are growing at an ever-increasing rate, reflecting the need for customers to receive broadcast TV programming services. best quality than what it has to offer The use of IP-TV is seen by many experts as the most logical development. That is, the only way the user will be able to choose programs, movies, as well as the time they are viewed. That is why it is believed that with mass connection using FTTx xPON technologies, this will no longer be a matter of the next five years, but only a couple of years. Every Internet service provider now understands that investment in optics is an investment for several decades to come, the return on which will exceed the costs by dozens of times. This can explain the active buying up of optical lines, as well as a number of pilot projects, including the laying of optics directly to the subscriber equipment.

What are the risks?

In the coming years, the FTTx Internet will not be the only option that can guarantee the provision of services over broadband access, but fiber optic infrastructure has a high enough potential that allows you to be sure of the return on all investments. At the moment, a lot of activity is typical for the modernization of backbone networks, and the FTTx technology market is still at the stage of study, design and testing. However, now there is an interest of operators in WDM elements, as well as passive optical splitters. In addition, sales of high-capacity optical cross-connects, which are also used in FTTx solutions, are expected to grow.

Types of architectures

FTTx technology (Rostelecom) includes several types of architectures:

FTTN (Fiber to the Node) - fiber reaches the network node;

FTTC (Fiber to the Curb) - fiber reaches a microdistrict, block or several houses;

FTTB (Fiber to the Building) - fiber reaches the building;

FTTH (Fiber to the Home) - fiber reaches the home.

The main difference is how close it gets to the user terminal. The first solutions to appear were FTTN and FTTC. The first solution is currently used exclusively as a quickly implemented and budget solution where there is a copper distribution infrastructure, and laying optics is simply unprofitable. The difficulties associated with such a solution are known to all: the low quality of the services provided, associated with the specific problems of copper cables located in the sewer, a significant limitation on the speed and number of connections in one cable. FTTC is an improved type of FTTN that does not have the disadvantages of the latter. In the case of FTTC, copper cables are laid only inside buildings, which means that they are not subject to destructive factors, and also do not have a long line length, the quality of the copper conductors used is also important. That is why it is possible to achieve greater speed in the area without fiber. This offer is valid when connecting using FTTx PON technology. This architecture is aimed at operators who are already actively using xDSL technology, as well as cable television operators. By implementing such an architecture, they can not only reduce costs, but also increase the number of connected users, as well as the bandwidth allocated to each of them. This type of connection in Russia is most often used by operators of small Ethernet networks, which is associated with the low cost of copper solutions, as well as the need for a highly qualified contractor to install an optical cable.

Factors

The placement of equipment that terminates the optical component of the communication line using FTTx xPON technologies depends on a number of reasons:

The presence of alternative infrastructure or its absence;

Opportunities to place active equipment in the house;

Number of connected subscribers;

Experts say that there is a very specific classification of terminal FTTx devices, which is tied specifically to the “x” point. The set of services offered depends on the type and number of interfaces used in the end device, as well as the mechanism for traffic control. If it is necessary to preserve the existing infrastructure, it is worth focusing on FTTC / FTTB systems that have an optical uplink interface. Such systems are suitable for large enterprises, in residential complexes and business centers where there is an existing copper infrastructure.

conclusions

The organization of networks using FTTx technology is most economically justified in the case of a significant concentration of solvent customers or new construction, when the issues of organizing cable laying are still at the decision stage. It is desirable that the network be planned so that the point "x" is located as close as possible to the client, that is, the subscriber. When building new districts, it is best to bring it directly to the building, it will be convenient both at the initial stage and in the future. This offer is valid when connecting using FTTx xpon technologies.