QUBIX POL/GPON solutions

A LAN (Local Area Network) is a hierarchical star topology network covering a small geographic area such as an office, school or building. It deploys mostly copper cables in Cat 6 or Cat 6A to connect all the terminal devices to the switches located inside the rack cabinets. Fibre optics are used only to connect the racks together. Network management is centralized with administrators configuring and monitoring devices and connections.

A POL network (Passive Optical LAN) uses mostly fibre optics to provide connectivity. It deploys a point-multipoint topology with a single optical fibre cable from an OLT (Optical Line Terminal) that branches out to different ONTs (Optical Network Terminal) through passive splitters. The use of copper cables is reduced and limited to the terminal connection of the devices to the ONTs. Network management is centralized and the maintenance is simplified thanks to the reduction of the active components and the higher reliability of fibre optics.

One of the main components of a POL network is the optical splitter. It splits the optical signal from the OLT into more outputs switching from typical P2P network to a P2MP topology without reducing the available bandwidth.
Splitters have a splitting ratio of 1xN up to 1:128 or 2xN type for the deployment of redundant networks.

The ONT (Optical Network Terminal) is an active device positioned downstream of the fibre link acting as the termination point of the POL network. It converts the optical signal into electrical signals and vice versa. It features an optical port for the connection to the OLT and one or more LAN copper ports and possible wireless connectivity for access to network services for connected clients.
Downstream of the ONT there can be a network switch to further extend the number of available links or to power any remote devices in PoE.

For the realisation of the POL infrastructure single-mode fibre cables are used, preferably of the bending loss insensitive G.657.A2 type.
For indoor or outdoor backbone sections, paths are straighter and the bending radii do not cause attenuations such as to justify the use of specific fibres. In this case optical fibres of G.652.D type can be used.

Thanks to the technical characteristics of the single-mode optical fibres used in the POL, the distribution network can reach the length of 20 km without using any intermediate active device.
The use of passive optical splitters that do not need to be powered, enables further splitting of the optical signal to add new user connection points quickly and easily.

The POL architecture can also be used in coexistence with traditional copper networks for the implementation of new endpoints where their addition would require redesigning the entire infrastructure.

An important advantage of POL networks, especially for installations in critical environments, is the immunity of optical fibres to noise, to Alien Next and electromagnetic interferences.

This, combined with the cryptography and the management/identification systems of the ONT integrated in the PON protocol, increases considerably the security level of the data transmission by limiting the possibility of intrusion and attack by hackers or unauthorized users.

The most common implementations on POL networks use the GPON standard through which it is possible to reach transfer speed of 2.5 Gbps in downstream and 1.25 Gbps in upstream.

This feature, together with the dynamic allocation of the band managed by the protocol, fully answers to the current connectivity needs.

Thanks to the potentially infinite bandwidth of the single-mode fibre optics, POL networks are also easily scalable and ready to support upgrades to future technologies like 10Gbps or the 25 Gbps to allow the quick and cost-effective implementation of new applications keeping the existing infrastructure unchanged.

A POL infrastructure compared to a standard LAN network is characterised by a strong reduction of the costs of the materials and of the installation time.

This is achieved through the optimization of the cabling, because of the smaller number of cables and of the technical spaces needed for the housing of big network cabinets, active devices and UPS.

Further to these advantages are also the longer longevity of a fibre-optic cabling and the lower maintenance costs as there are no intermediate electrically powered devices. PON networks are also economically competitive as all ONT active devices are centrally managed by the OLT.

A copper LAN network, because of the limits set by the connection distances, typically needs intermediate switches and distribution cabinets equipped with ventilation and cooling systems that are energy consuming.

A POL network on the other hand, uses only passive components from the OLT to the different ONTs and no intermediate devices are needed, meaning a lower total energy consumption.

In the case of PoE systems, the shorter distances of connection lead to a further savings because of lower power loss along the copper link.

POL infrastructure is a very advantageous solution with a high cost/benefit ratio especially in the hospitality sector. Camping, resorts and hotel guests can have access to the services offered by the structure such as data/TV connectivity in a simple and secure way.

Flexibility of configuration, possibility to reach distant locations or to add new links far from each other, make it preferable to other types of networks structurally more demanding.

POL networks offer to accommodation facilities (hotels, residences and BB) the ability to provide fibre connections to each room by granting the supply of the services such as data connection, TV on demand, voice and access control, etc.

POL technology can help hospitals, clinics and health-care facilities to provide the best possible patient care.
The savings represented by lower construction and maintenance costs together with the very high available bandwidth, help in implementing monitoring and diagnostic systems to grant the patients a better, prompt and efficient service.

Connection to the digital world in universities and schools allows real-time collaboration between students and teachers, new approaches to research and distance learning.

POL networks enable the development of broadband cabling infrastructures that simplify the interaction between users, as well as sharing and availability of information.

POL networks are widely used in airports to ensure efficient and secure management of communications and data. Thanks to the use of fibre optics, these networks offer high performances in terms of speed, reliability and ability to cover wide areas without signal loss.

POL are ideal to support critical applications such as air traffic control, video surveillance, baggage handling and the communication system between staff. Moreover, their energy efficiency and the lower OPEX/CAPEX costs contribute to improve the sustainability and overall efficiency of airports.

A POL network with both primary and secondary splitters works on 2 levels of splitting of the optical signal. OLT signal is first divided by a primary splitter, installed in an optical patch panel in the campus distribution cabinet, usually with a ratio of 1:2 to 1:8. Each output of the primary splitter is further divided by a secondary splitter, positioned in an optical floor box with a ratio from 1:4 to 1:16. This approach allows to serve up to 32 ONT through a single OLT port. The dual splitter configuration reduces the need for extended cabling and improves the network efficiency making it ideal for environments with a high density of users.