For our FTTH access network, we decided to follow the evolutionary roadmap of Passive Optical Network (PON) technology, which conceives, as a first step, the introduction of GPON (Gigabit Passive Optical Network) technology, currently the most solid fixed access technology on PON networks, and subsequent evolution towards NG-PON and NG-PON2 technologies that will allow a progressive and considerable increase in transmission capacity.

The Open Fiber FTTH access network is a multi-operator passive network that supports the use of point-to-multipoint and point-to-point technologies.

The OF “point-multipoint” architecture is based on the implementation of a network in which the optical concentration resources (PON Trees) are shared by the various operators, while the final connection with the user is implemented with a single dedicated fiber.

In order to collect users in an efficient manner, a network element has been introduced, consisting of an exchange cabinet (coinciding with the PFS node) in order to connect each customer, in a flexible manner, with the optical resources of the operator whose service the latter has subscribed to.

OF GPON architecture

Future-proof technology

The evolutionary trajectory of PON optical access network technologies envisages a progressive increase in the bandwidth available to customers.

The evolution of GPON technology is a key aspect for the telecommunications industry and Open Fiber’s FTTH access network is able to support it, thus ensuring a series of new services to be enabled with increasingly stringent bandwidth requirements.

The services provided on the PON network are addressed to residential and business users with connectivity services in symmetrical and asymmetrical configurations. Thanks to the evolution of PON technology, it will also be possible to support high-capacity backhauling and fronthauling links for advanced mobile radio systems.

The following technologies are envisaged in the evolutionary roadmap of PON networks:

GPON (2,5Gbps/1,25Gbps)
XG-PON (10Gbps/2,5Gbps)
XGS-PON (10Gbps/10Gbps)
NG-PON2 (min 4x10Gbps/2,5Gbps)

The maximum speed in Downstream and Upstream is indicated in brackets.

A modern transport network

Open Fiber is developing a modern national transport infrastructure which will make it possible to collect traffic from the FTTH access network and deliver it to operators, ensuring equal access and service conditions, regardless of whether the point of delivery is local or remote.

In this sense, the network enables a complete portfolio of services to be offered in order to meet the needs of an increasingly heterogeneous market, from end-to-end connectivity with guaranteed bandwidth and controlled latency, to the future offering of a network and computing infrastructure to host physical and virtual third party functions, all in order to improve the customer Quality of Experience, support the delivery of high-resolution video content, offer security solutions and Internet of Things (IoT) platforms.

Open Fiber has a transport network with an open, carrier-grade, programmable, high performance and scalable architecture, which allows Operators to provide innovative ultra-broadband services while simplifying configuration and management activities.

For the configuration and management of transport services, Open Fiber uses innovative Network Automation techniques that create automated workflows, which receive the work order from the CRM and activate it on the network, speeding up the lead time for the release of new services and reducing the possibility of errors, thus improving the Quality of Experience perceived by customers.

The Open Fiber Transport Network envisages only two levels:

  • a core or national backbone network
  • an aggregation network (primary and secondary)

The design of the national backbone is based on two domains: one optical (OTN/WDM), to manage transmission with the most efficient techniques and at the lowest cost, and one electrical (IP/MPLS) for the processing and routing of packet traffic. It ensures optimal use of valuable transmission resources, quality of service throughout the chain, as well as process flexibility and automation to rapidly deliver traditional and innovative services.

The National PoPs are distributed in such a way as to ensure full coverage of the entire country and envisages very high capacity optical connections (100/200G coherent lambdas).

The backbone network is implemented thanks to an intelligent EON (Elastic Optical Network) type DWDM (Dense Wavelength Division Multiplexing) optical partial mesh, high capacity and scalable network. ROADMFLEX multi-degree (Reconfigurable Optical Add and Drop Multiplexer) and GMPLS/WSON (CD – Colorless, Directionless) technologies are used with which it is possible to simultaneously aggregate multiple optical channels on a single fibre optic cable and thus manage an increasing number of customers and services, thus fully exploiting the very high transmission bandwidth of fiber, in the order of the Terabit (1,000,000 Megabits). A capacity unimaginable until just a few years ago, which will support the Ultra-broadband applications that will be developed in the coming years (high resolution video, virtual reality, augmented reality, tactile Internet, real-time gaming, autonomous driving) and in general the innovative services of future 5G networks.

The aggregation network, consisting of Edge POPs and with high capacity optical connections, provides Level 2 functionality as well as support for the MPLS protocol where necessary, in order to provide the wholesale services required by operators.