We all know what campus networks are, but have you heard of OLAN or POL?If you type OLAN in the Web browser, you will get an answer relatively quickly, while for POL the situation is more difficult.Simply put, optical cables are being introduced into LAN and campus networks, UTP cables are being suppressed or significantly reduced, and many problems of traditional local area networks are being solved.It all started with networking computers with coaxial cables, which then enabled an incredible 10 Mbps in the bus topology.Due to numerous shortcomings, coaxial cables were soon replaced by UTP cables, so we switched to star topologies, ring and the like.Data transfer speeds began to increase from 10 to 100 Mbps, then from 100 Mbps to 1 Gbps.And that's about it.Or not…Recall the architecture of the campus network.It consists of a main switch in a computer room (computer room or main equipment room), local switches in telecommunication rooms (telecom closet or telecom room), vertical cabling, which provides communication between the main switch and local switches and horizontal cabling, which allows connecting a computer to a local switch.The maximum distance of the permanent link is about 90 meters.Every telecommunication room requires enough space, patch panel, switch, power supply, UPS, maintenance… In short, too much equipment and too many demands.Now let's see what OLAN has to offer.The superiority of optical cables is generally known to everyone, and that superiority has been transferred to both LAN and campus networks.With the introduction of optical cables, we get almost unlimited data flow (especially when we talk about single-mode (SM) optical fibers), immunity to interference, freedom when it comes to link length (links can be 20 or more kilometers), fewer cables, lower consumption electricity because we do not need telecommunication rooms, less maintenance and many other benefits.With the introduction of optical cables, we get almost unlimited data flow, immunity to interference, freedom when it comes to the length of links, fewer cables, less power consumption, less maintenance and many other benefitsAnd problems or shortcomings?There are them too.The most important are the additional requirements for careful installation of optical cables so as not to damage or significantly bend and thus disable the normal operation of the system, then the requirements for special tools, splicer and trained staff to connect optical fibers (splicing) and finally testing and troubleshooting. an environment that is much more complicated and demanding in terms of expertise and the need for tools (fiber stripper, fiber cleaver, etc.) and instruments (PON meter, OTDR, VFL).OLAN networks, however, offer great advantages.The world's leading companies in the PON (Passive Optical Network) industry, such as Huawei, Nokia, Calix, have been successfully implementing this solution for years.OLAN offers three solutions: FTTD (Fiber To The Desk), FTTO (Fiber To The Office) and the most popular POL (Passive Optical LAN).FTTD is a solution that uses multimode (MM) optical fibers and media converters as terminal devices.In the computer room there is a main switch that communicates with media converters via MM fiber optic cables.There are five types of MM optical fibers - OM1, OM2, OM3, OM4 and OM5.In short, its range and data flow depend on the type of MM optical fiber.OM1 is the first version of MM optical fiber, which is no longer used.FTTD typically uses OM3 or OM4 optical fibers.These types are also used in modern data centers.OM3 and OM4 use VCSEL (Vertical Cavity Surface Emitting Laser) light source at a wavelength of 850 nanometers.MM optical fibers, just like SM, can be flattened or used with factory-fitted optical connectors.The most common are LC / PC (Lucent Connector / Physical Contact) and SC / PC (Standard or Square Connector) connectors.The media converter converts the optical signal into electrical and establishes a service via the Ethernet interface.They usually require two MM optical fibers with LC / PC optical connectors.They usually have one GEth port, but they can also be found on the market with four GEth ports.Some of them also support PoE standards and thus allow remote powering of certain devices, such as IP cameras and VoIP phones.If there are not enough Ethernet ports on the media converter, a switch can be added to connect all hosts.We use UTP cables, usually categories 5e, 6 or 6e, to connect hosts to media converters.FTTO is a similar solution to FTTD, except that SM optical fibers and local switches are used to connect hosts.The architecture is the same as for FTTD: in the computer room there is a main switch, which communicates via SM fibers with local switches located in offices / rooms.And again UTP cables, to connect hosts.SM optical fibers can be OS1 and OS2 (low water peak fibers).Due to better performance, OS2 is usually used.Two optical fibers are used for communication, and as optical connectors they are usually SC / PC or LC / PC.And finally, the most popular solution: POL, Passive Optical LAN.POL is, simply put, FTTH for LAN and campus networks.In the computer room, instead of the main switch, there is an OLT (Optical Line Terminal), and ONU (Optical Network Unit) or ONT (Optical Network Terminal) are used as end users.Vertical and horizontal cabling is realized with optical cables with SM fibers.Optical fibers are divided into 32 or 64, in one or two levels of division;it all depends on the configuration of the object.There is usually at least one ZOK (so-called "final optical box") with an optical splitter on each floor.The POL solution uses mainly GPON (Gigabyte Passive Optical Network) or XG (S) ONPON (10 Gigabyte (Symmetrical) - PON) standard.The POL solution replaces at least three cables per room with one optical fiber.Space savings are significant, electricity consumption is lower, and management and maintenance are easierOLT is the main element of the POL system, it is located exclusively in the computer room.It also enables the connection of various services to ONT devices via the optical infrastructure.It can be of different capacity, ie the number of service cards - from the so-called.pizza box OLT with integrated PON ports up to OLTs that can have 15 or more service cards with a maximum of 16 PON ports.A maximum of 128 ONTs can be connected to each port, but up to 32 or 64 ONTs are usually connected.The main reason is the flow of data, and much less the optical budget.Each room (office, hotel room, hospital room) received one optical fiber and one ONT, which enables a larger number of services.ONT is a device that converts a signal and enables services on its interfaces.There are different types of ONT devices, and they are divided into two large groups: bridge ONT and gateway ONT.Bridge ONT usually has only one GEth port.As for the ONT gateway, the offer is wide.Variants with four GEth ports, one or two POTS (Plain Old Telephone Service) ports, one RF (Radio Frequency) port and Wi-Fi are commonly used.We could not provide services such as digital cable television or fixed telephony via the traditional LAN and campus network.Special cables were required for each of these services.The POL solution replaces at least three cables per room with one optical cable / fiber.Also, significant are space savings (about 60 percent), savings on cables, lower electricity consumption (more than 50 percent), easier management and maintenance (less than 50 percent)…As we can see, there are many advantages of OLAN solutions, especially POL.The main POL markets are currently in Asia, North and Latin America and the Middle East.According to the non-profit organization APOLAN (Association for Passive Optical LAN), the global POL market for 2019 was estimated at 280 million dollars for equipment alone, so that the crisis due to the COVID-19 pandemic would slow down development.Cisco's entry into this market further confirms POL as a quality and reliable solution.In the coming years, strong growth of this market is expected in all regions.Your email address will not be published.Required fields are marked *