How to quickly and cheaply build a PON in the private sector
To date, the only correct way to develop the private sector is PON technology. Provided that there are more than 20-30 subscribers in the private sector, this is the most correct and already the cheapest approach to solving such a problem. The most difficult questions arise already at the stage of the birth of the idea itself. Manufacturer's choice? How to design a network so that in the future there will be less worries and troubles? How to choose the right passive equipment?
In this article, we propose to consider one of the approaches to building a network in the private sector. The provider who helps us in this article wished to remain anonymous. At the same time, his experience in operating the GEPON network exceeds three years.
Let's start with the fact that in the recent past, station and subscriber equipment manufactured by Eltex was chosen. At that time, this solution was the most workable. Top notch technical support. Many bugs were added already in the field, but there are more pluses than minuses. In a short time, the operator was able to achieve the work of the equipment, which was needed. Now it is already a fairly well-known manufacturer of GEPON and GPON equipment and does not need additional mention.
For three years, the provider has tried many approaches to building a network, used different splitters with different division ratios and in different versions, went through a couple of couplings and, finally, came to maybe not an ideal, but the most optimal solution.
On the station side there is an optical line terminal OLT LTE-2X or LTE-8X (depending on the number of subscribers and the location of the nearest exchange to them). For providers who are just deciding to start using the technology, it is best to take LTE-2X - everything you need is here: two PON 2.5G ports with 64 subscribers per port, as well as 4 combined 1G ports with a chassis for SFP 1.25G, which, if necessary, can be aggregated into one channel. If the company is self-confident and has a sufficient number of subscribers, then it is more profitable to take LTE-8X - 8 PON ports with a total capacity of up to 512 subscribers, there are already two 10G ports, and also 4 combos.
For example, consider the station terminal OLT LTE-2X. Our consultant operator uses both LTE-2X and LTE-8X.
When using two ports at once, it is better to switch them to an 8-port cross with SC / APC adapters. An 8-fiber OPTs-8A-4 cable enters the cross
On the entire section from OLT to drop (drop-cable - the last section to the subscriber), we use an 8-fiber cable. Convenient, there is always a reserve, you will never confuse. The cable is always in stock from suppliers. There are no questions at all. If you want to save money, you can use OPTs-4A-4 on the longest section.
Initially, the first entry into the private sector was carried out in the residential building of the manager or in the security house, but the company decided to get rid of such a solution. There are only minuses here: coordination, location in the house, cable supply, cable output, full access to your locker. Very uncomfortable. In the age of new technologies, the most correct thing here is to reduce the size of passive equipment. And since there is only a splitter from passive equipment, the dimensions of which now do not exceed a third of a pencil, everything conveniently fits into one clutch.
It is desirable to use the first clutch with a margin for the number of incoming and outgoing cables. Many have already developed their own tastes for certain mutes, the main thing here is that you can work with nine 8-fiber optical cables. The 8-fiber cable is small in size and easily fits two or three cables into one entry without steel wire.
Do not forget that we have two working fibers in the cable - two PON lines.
Optical division of the signal in the fiber is carried out by a passive optical splitter. The small design of the splitter allows you to lay it in a lodgement on a splice cassette and secure it with mounting ties. The splitter has one (rarely two) input and eight outputs. The division of the signal occurs evenly to all subscribers.
(Note: To all PON subscribers - packets are broadcast from the OLT and received in the OTN according to the MAC address; on the subscriber side, all ONTs are synchronized from a common timing source and each ONT is allocated a specific time domain).
To connect (up to) 64 subscribers to one PON line, a bundle of 1/8 splitters plus 8 more 1/8 pieces is required. Where the density of houses is high, it is recommended to use the optical budget to the maximum and connect 64 subscribers per branch. Where there are not many subscribers, you can turn on splitters and a different division factor. Here you need to navigate the area.
In the first clutch, we switch one core from the cable that came from the station to the splitter, and connect eight similar cables that already diverge in the right directions in the private sector. The first clutch is not supposed to switch, and in order to save the power budget, we use fiber splicing. The second untouched PON - line can be included in any of the following cables, in the one that is closest to the next part of the subscribers or where the most connections are predicted to be.
At the design stage, it is not possible to know one hundred percent where and who wants to connect. Over time, new plots of land can be developed, new houses and, consequently, new subscribers can be built. Therefore, it is recommended to make a supply of cable on a pole in such “areas”. Then you can always plug in a new clutch and pull out subscribers or even send one of the cores in another direction. A supply of cable is worth nothing in price, but the benefits in the long run are much greater from a kind of mobility in the selection of fibers.
So, we reach the first subscribers. And here we use a unified 1/8 splitter. Everything is the same, the cable is included, switching with a splitter, etc. It is recommended to use special FTTH couplings in the last section. These couplings are distinguished by their low cost and convenience. There are two to three inputs for line cable and 4/8/16 outputs for FTTH cables (or drop cables). And also, in the coupling, you can use welding or cross-linking with detachable connections. In this case, you can connect all the outputs to the cross-panel at once. As a drop-cable, we use the OPTs-4A-4 cable. Now there are already a large number of FTTH cables on the market at the most affordable prices, and it is possible to use them. But now we are analyzing a specific case that has already been tested! The OPTs-4A-4 cable is convenient to use, and when approaching the house and wiring, the steel bar is removed and you can enter the room. In the premises, most often the wiring is carried out by agreement with the subscriber, since he will be better off. For example, it can be switching to a patch cord and installing an ONT in any of the rooms.
Let's move on to the important advantages of working with PON technology, which must be taken into account during construction. We have already talked about the supply of cable and mobile allocation of subscribers. How to achieve this? Due to the fact that the 8-fiber cable is almost empty, it is easier to “wrap” several subscribers back in the second sleeve and select them in any of the return sections, where a reserve has been made on the pole in advance. This is an important advantage that saves quite a lot of expensive resources that may arise when connecting new subscribers.
Using these seemingly simple tips, you can quite economically and efficiently build a GEPON network (or GPON, whichever you prefer) with minimal investment both at the initial stage and at the stage of network development.
Everyone has the right to choose the path of development of their network, but our consultant, using passive signal separation technology, has never regretted it. From the name of the technology itself, its advantages follow. If we take into account such moments as organizing the placement of active equipment indoors in the private sector, grounding according to all standards, guaranteed power supply and much more in terms of the number and name of equipment, then PON technology is a cut above.
In order to start building and connecting you will need approximately 70% of the cost of the first specification. Subscriber devices can be purchased as subscribers grow.
For the material provided, we thank the participant of the project "new-seti.rf" Sergey K.
