FTTH Handbook. Revision 1 Feb Ethernet Point-to-Point. Conventional Duct Infrastructure. Feb Cable Joint Closures.
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FTTH Handbook. Revision 1 Feb Ethernet Point-to-Point. Conventional Duct Infrastructure. Feb Cable Joint Closures. Direct Buried Cable Infrastructure. Aerial Cable Infrastructure. Internal Cabling. Network Elements. Optical Splitters. Network Planning Guidelines. Operation and Maintenance Guidelines. This handbook has been developed to provide an understanding of all the elements associated with a Fibre-to-the-Home FTTH network infrastructure.
Inside are details of the many different network infrastructure deployment options that can be considered when planning and building a FTTH network within Europe.
It is up to the network designer to decide which design methodology is the most appropriate to use. This document is limited to providing and overview of existing technologies and should not be taken as a design guide.
Optical fibre will be the main building block for future high capacity home broadband networks. Its transmission capacity is almost unlimited and unconditional compared to existing copper cabling systems. Numerous financial models have shown little difference between the deployment costs of optical fibre and copper cables systems of equal capacity.
However, the advantages of fibre offering high bandwidth and future upgrade potential over large distances and secondly much lower maintenance and operations costs make fibre an obvious choice. All deployment options discussed in this handbook are based on a complete optical fibre path from the serving active equipment right through to the subscriber premises.
All of the infrastructure deployment options described are currently available and have been successfully deployed throughout Europe and the rest of the world.
These can be used either in isolation or in combination with the other options to form the most efficient overall solution for specific deployment circumstances. When providing FTTH networks, it is key to understand the challenges for potential network builders and operators. Some of these challenges may present conflicts between functionality and economic demands. Key functional requirements for a FTTH network will include:. To describe an FTTH infrastructure network it is essential to understand some of the basics.
An FTTH network constitutes a fiber-based access network, connecting a large number of end users back to a central point known as an Access Node. Each Access Node will contain the required active transmission equipment used to provide the applications and services over optical fibre to the subscriber. Each A ccess Node is served by a larger metropolitan or urban fibre network , connecting other Access Nodes throughout a large municipality or region.
Access Networks may connect by optical fibre some of the following:. The deployment of fibre closer to the subscriber base will require that consideration be given to infrastructure deployment on public and private land, and also within public and private properties. The environment can be broadly split into:. Not only does each environment offer different customer densities per sq km , but this also varies by country.
The type of site will be a key factor in deciding the most appropriate network design and architecture. The main influences for the fibre infrastructure deployment methodology will be determined by:. The fibre deployment technology will determine both Capex and Opex but also reliability of the network, and it is optimised by a mix of the most appropriate active solution combined with the choice of deployment technologies broadly grouped below.
These are described in further detail later in this paper. In order to specify the interworking of passive and active infrastructure, it is important to make a clear distinction between the topologies used for the deployment of the fibers related to passive and the technologies used to transport data over the fibers related to active.
The two most widely used topologies are point to multipoint using Passive Optical Network PON technology and point to point, typically using Ethernet transmission technologies.
Service Delivery. Active Infrastructure. Passive Infrastructure. Point to Point topologies provide dedicated fibers between the POP and either the subscriber or a first active aggregation point in the network. Each subscriber is directly connected by a dedicated fiber on the POP. A wide choice of transport technologies is available. Various access network architectures can be implemented.
The connections between subscribers and the building switch can be fiber or copper based and also use some form of Ethernet transport suited to the medium available in the vertical cabling. In some cases building switches are not individually connected to the POP but are interconnected in a chain or ring structure in order to utilize existing fibers deployed in particular topologies and to save fibers and ports in the POP. This document will however concentrate on FTTH deployments because in the long term they are considered the target architecture due to their virtually unlimited scalability.
This phenomenon is mainly due to the fact that most of the initial European deployments were made by municipalities who were effectivel y working in Greenfield scenarios, i. Connections between end-users and the building switch can either be copper or fiber although fibre is the only solution that will guarantee the ability to manage future bandwidth requirements.
In some countries a second fibre is provided for radio frequency video overlay systems. There are pros and cons for every case and the choice is highly dependent on the availability and usability of the passive infrastructure.
Point Point of of. Presence Presence. Home Home. Optical splitter. Up till now, there have been several generations of PON technology. Trends for access technology over the next ten years will be towards a higher ratio of upstream-to-downstream bandwidth. While fairly minimal now, new applications utilizing peer-to-peer technology, multimedia file sharing, and the general trend towards more data- intensive e-mail and enterprise applications used by workers-at-home will drive subscriber upstream bandwidth.
Still, it is difficult to envision complete symmetry in residential applications due to the enormous amount of bandwidth required for HDTV and entertainment services in general although small business services can benefit from symmetric, broadband connectivity. Nonetheless, current and future mechanisms in PON systems enable asymmetric or symmetric balance of bandwidth, and it is the high upstream bitrate of the PON that gives FTTH providers a main com petitive market advantage over DSL or cable providers.
Reach can be extended to 30 km by limiting the splitting factor max EPON can also provide a 20km reach with a 29dB optical budget. As indicated below: Radio Frequency Video overlay. Passive Outside Plant. Video Optical Line. The Optical Line Termination boards can cope with up to approximately subscribers based on a max 64 per GPON connection per shelf. There are different Optical Network Terminations to suit the location:. Optical Lin e T erm in al.
When deploying fiber access loops, active and passive infrastructure go hand in hand. It is clear that the timely investment in active equipment mainly at network side can be optimised once the right passive splitting architecture has been chosen. With single level splitting, the splitter can be placed closer to the customers in case of important end-user density, such as high rise buildings or can be placed more centralised to improve the spread of customers in case of less dense end-user locations.
Knowing the current and future customer distribution and location is of the utmost importance when planning splitter placement. Further optimisation can be achieved by distributing the splitters in more than one level reducing the fibre required and easing the configuration but increasing the number of positions where splitters are installed. For Ethernet PTP, there are two possibilities, one dedicated fiber per customer between the Ethernet switch Point of Presence and the home or one fiber to an aggregation point and dedicated fiber from there onwards.
The former possibility is easy and straightforward to implement, the latter limits the fiber usage in the access loop and is therefore suitable for FTTB Fiber To The Building solutions. From a civil engineering perspective the topologi es for point-to-point fiber deployments are identical to those for PON. From the POP location individual feeder fibers for each subscriber are deployed towards some distribution point in the field — typically a splice point — either in some underground enclosure or a street cabinet.
From this distribution point drop fibers are laid towards each individual household. As fiber densities in the feeder and drop part are very different, often different cabling techniques are employed, depending on the specific circumstances. In the feeder part deployments can be greatly fa cilitated not only by existing conventional ducts, but by other rights of way, like sewers, tunnels, or other available tubes.
The higher number of feeder fibers does not pose any major obstacle for point-to-point installations. In the POP the fibers arriving from the outside plant are terminated on an Optical Distribution Frame ODF as the fiber management solution which allows to flexibly connect any customer to any port on switches in the POP. Due to the large number of fibers to be handled in a POP the density of such a fiber management solution has to be very high in order to minimize real estate requirements.
To the right is an example of a high- density ODF that can handle more than fibers in a single rack. For illustration purposes it is positioned next to a rack with active equipment that can terminate fibers on individual ports.
The fiber management allows a ramp up of the number of active ports in sync with the activation of customers. This minimizes the number of unused active network elements in the POP and enables a slow ramp up of the investments. Both specifications are defined for a nominal maximum reach of 10km. The following table provides the fundamental optical parameters of these specifications.
Transmit direction. Nominal transmit wavelength. Minimum range. Maximum channel insertion loss. In order to cope with requirements not considered in the standard the market also offers optical transceivers with non-standard characteristics. Some types can bridge significantly longer distances, e.
FTTH Handbook 2010 v3.1