Solutions for addressing the challenges of fibre optic rollouts in MDUs

In Europe, more than half of the population lives in apartment buildings. In urban areas the proportion rises to 70% or more. While it is clear that connecting buildings is a key step in the digitalisation of societies, telecom operators and their subcontractors face many challenges for deploying fibre networks in Multi-Dwelling Units. Unlike enabling fibre connection in SDUs, where the owner’s agreement is enough to start the rollout work, in MDUs the access to the subscriber is made through the common areas of the building, subject to co-ownership regulations. Thus, before starting the fibre rollouts, telecom installers may have to wait up to a couple of months before a wayleave is granted by the condominium association. This can lead to significant delays in FTTH/FTTO deployment projects and, depending on the decisions taken during the assembly, have a direct impact on the nature of the network equipment to be installed.

Also, the variety of network architectures specific to MDUs, as well as the different local regulations to be met, make the task of fibre optic network installers very complex as each deployment may require specific fibre connectivity solutions.

To optimise FTTH/FTTO deployments, during the planning phase, it is important to take into consideration three different dimensions impacting every project:

  1. The CAPEX : the global cost of the network equipment to be installed for setting the optical network.
  2. The installation cost: this implies the labour cost and the associated expenses for a succesful fibre rollout in MDU. Depending on the selected FTTH/FTTP solutions and the required skills, this cost may be more or less important.
  3. OPEX – the cost associated with the maintenance operations of fibre optic networks.

Choosing the right network equipment from the fibre BEP to the subscriber socket FTTH

To ensure that you make an informed choice when selecting the network equipment for connecting a MDU to very high speed fibre networks, it is recommended that you carefully analyze the whole project. For instance, it is important to determine:





  1. The MDU type: brownfield or greenfield. Depending on the nature of the building and the condition if the infrastructure to be exploited, the FTTH/FTTP rollout may be more or less difficult to perform. Also, this has a direct impact on the connectivity solutions to be chosen.
  2. The number of storeys. Knowing how to scale the optical network is the key to any fibre network rollout optimisation. It is therefore important to choose FTTH connectivity solutions that are dimensioned to accommodate the maximum number of subscribers to be connected to ultrafast broadband full-fibre networks.
  3. The number of appartment flats per storey. Both the fibre optic cabling solutions and the optical boxes to be installed at the storey level must be correctly dimensioned to enable the connection of all subscribers without however wasting fibre or space in the distribution or termination boxes.
  4. The take rate/business case. This is the percentage of potential subscribers for whom the service is made available who actually do subscribe to this service. A relatively low or high take rate will determine which network equipment is more suitable to be installed in terms of FTTH cabling solutions or test points present in the optical network.
  5. The pace at which the FTTH/FTTP rollout should be performed. Whenever this becomes a strong constraint, telecom installers should opt for pre-terminated optical connectivity technology which will help them save a considerable amount of time. In case the FTTP rollout does not have to be done at a fast pace, both solutions are to be considered: pre-terminated and for splicing applications systems.

Optimising the FTTH rollout from the building connection point to the subscriber

To know which type of network equipment is the most appropriate for your full-fibre rollout, we have chosen to showcase three scenarios, most commonly met in the field:

1.Small size MDU (a dozen of flats).


Rollout type



Network equipment to install from the fiber BEP to the customer’s premises








P2P topology – indoor rollout

  • A Building Entry Point (optical distribution box) mounted at the ground floor level or in the basement
  • A drop cable per customer
  • An optical outlet per subscriber


  • Low CAPEX
  • Aesthetic installation

Often, cable running and routing is difficult as ducts are already occupied or reserve very little available space.

Facade rollout


  • An outdoor optical distribution box such as the Eline® Outdoor ODP with enough capacity to enable connections for the entire MDU, if necessary
  • Indoor drop cables in a proportional number with the subscribers to be connected
  • An optical socket per subscriber for enabling the network termination in the room where the ONT is placed.

Solution for MDUs with very occupied/ saturated ducts

Less aesthetic


2.Mid-size MDUs (up to 40 flats).


Rollout type



Network equipment to install from the fiber BEP to the customer’s premises








Indoor rollout using a riser cable


  • A BEP optical distribution box mounted at the MDU’s ground floor or in the basement
  • A riser cable enabling the vertical optical distribution at all levels of the building
  • A FDB (Floor Distribution Box) per storey used for protecting the connection between the fibres coming from the riser and the ones from the drop cables
  • Drop cables for indoor applications
  • An optical socket (OTO) per customer


  • Reliable networks
  • A relatively low cost of network hardware to be installed in comparison with rollout using pre-terminated solutions or a P2P topology (one cable per subscriber)
  • The labour cost is lower than for the installation of a P2P network, but higher than the one engaged when using pre-terminated technologies

Longer time required for connecting a building to the full-fibre Gigabit-capable networks


3.Large-size MDUs (up to 120 flats).


Rollout type



Network equipment to install from the fiber BEP to the customer’s premises








Indoor rollout using multiple riser cables, topology also knowned as “satellite”


  • A BEP mounted at the grond floor or in the basement
  • Various pre-terminated riser cables enabling the vertical optical distribution to the building’s different storeys, depending on their capacity and the number of homes to be connected
  • A pre-terminated FDB used for several storeys utilisé pour desservir plusieurs étages
  • Pre-terminated drop cables for indoor applications
  • A subscriber FTTH socket per subscriber, factory-terminated with adaptors


  • More reliable optical networks
  • Quick network rollout thanks the “plug & play” system
  • The labour cost is significant lower than in case of network rollouts using splicing technology

The deployment of this topology is conditioned by the free space required in the technical duct to be used. Telecom installers must ensure that the technical duct present enough available space for installing all the needed riser cables to connect all the apartments ( subscribers or home passed).


You have long understood that the choice of network equipment is an essential stage for ensuring a successful FTTH/FTTP rollout. The quality of the selected equipment, the ease of installation and re-intervention on the equipment are factors that will also play a major role on the cost associated with the network set up and maintenance. For all these reasons, Telenco networks cares to provide the most suitable FTTH/FTTP connectivity solutions for all full-fibre rollout projects.