Choosing the right fiber distribution hub (FDH) in MDU, rural and municipal deployments is important – and one size definitely does not fit all.

Fiber-to-the-premises (FTTP) deployments are providing the promises of fiber connectivity to households across the country in a variety of greenfield and brownfield applications comprised of different demographics and population segments. Service providers are seeking new customers in both high-density, multi-dwelling units (MDUs) and low-density rural areas. Municipalities are discovering the benefits that fiber optic networks bring to their communities in terms of new businesses and competitiveness.

Every deployment – and each density requirement – presents its own unique set of challenges, particularly in the area of fiber distribution equipment. This is demanding and requires changes from traditional equipment to new products designed for specific types of applications. As a result, service providers are becoming increasingly aware that when it comes to the fiber distribution hub (FDH) equipment, one size will no longer fit all.

The FDH houses the connections between fiber optic cables – feed and distribution cables – and passive optical splitters. They are strategically placed throughout the FTTP network to facilitate service connection and reconfiguration. For that reason, they require easy access to all termination and interconnection points.

This article explores how new FDH equipment designs are adapting to meet the unique considerations of several deployment situations. Whether building a fiber network for a municipality, or reaching subscribers residing in crowded MDUs or in sparsely-populated rural settings, choosing the right FDH product will ensure the necessary flexibility, accessibility, and scalability for avoiding potential problems in the future.

The In’s and Out’s of MDUs
MDUs come in all shapes and sizes, from rows of townhouses to towering high-rises, and each presents unique challenges to the network planner. There are more than 30 million MDUs across America and two-thirds of them consist of 5 units or more. Another consideration is the age of the building: while some applications will be greenfield deployments, others are retrofitting buildings that are hundreds of years old.

When installing a fiber network into an MDU, the service provider must have flexibility, aesthetic appeal, in-stock products, and the means to quickly install the equipment with minimal disruption of the tenants’ everyday lives. The fiber cable must enter each living unit, which requires installers to find creative ways of hiding the cable from view in areas such as hallways and common areas.

The distribution equipment for MDUs must be flexible to meet the specific needs of varied types of structures. The four most common MDU types are:
1. High Rise (100 or more living units on 10 or more floors).
2. Medium Rise (fewer than 100 living units on multiple floors).
3. Low Rise or Garden Style (single living units on each floor).
4. Horizontals (each unit resembling a single family unit). These buildings may also house commercial activities such as hospitals or hotels.

The FDH is a central piece of equipment for any FTTP deployment, feeding distribution fiber cables to multiple locations. Taking a medium-rise MDU for example, the FDH typically resides in the bottom floor or basement and connects to multiple fiber distribution terminals (FDTs) on each floor. Space can also be an issue, since the FDH is located inside within a wiring closet or telephone room. Yet, the FDH must provide the same features as a traditional outdoor FDH, such as easy accessibility, multi-splitter capability, parking lot storage for splitter outputs, and enough overall density to accommodate the entire MDU.

Therefore, in the case of MDU structures, service providers should seek products that are low-profile for space considerations and easy mounting, yet deliver the same flexibility, accessibility, functionality, and reliability. Slim, low-profile FDH products have been designed especially for MDU applications with a maximum depth of 8 inches or less. They can also accommodate densities of 72, 144, or 288 fibers - enough to connect most MDU structures.

Another important equipment consideration for MDU fiber distribution is plug-and-play distribution fibers. FDT can be connected using pre-connectorized cables using multi-fiber push-on (MPO) connectors. These products save installation time to get in and out quickly, while also cutting down on expenses associated with splicing and splice technicians. New innovations in fiber distribution equipment, from the FDH to the subscriber’s living room, are enabling service providers to efficiently “fiber-up” more MDUs in much less time, resulting in a very lucrative market for FTTP.

Reaching the Rural Neighborhoods
It’s not hard to imagine that the considerations for a rural FTTP network differ considerably from those in densely-populated MDU environments. In rural America, it’s not as much about the speed of installation as it is right-sizing the equipment to fit the take rate expectations. In other words, service providers neither want too much or too little density – and having a choice in FDH equipment that provides fiber counts from 72 to 864+ allows network planners to decide which equipment offers the best efficiency and cost points for their particular application.

Where the take rates are expected to be high, outdoor FDHs can provide the fiber density required in most greenfield or brownfield applications. An emerging trend among developers is to deploy their network in phases to reduce first-in costs associated with a one-time roll out of services. This works particularly well for greenfield applications that are gradually building out in sections, with units being built and occupied over an extended period of time.

For example, a development of 432 homes may begin with the first phase of 100 homes with subsequent build-out phases down the road. To accommodate this new trend, smaller pedestal-style FDH products are being manufactured for either a phased in approach or simply a smaller development. Figures 1 and 2 show a typical FDH pedestal designed for rural deployments.

These pedestals can provide smaller fiber counts, such as 72 or 96, that meet the demand for less density. The smaller pedestals offer the same features and benefits as their larger outdoor FDH cousins – easy access, plug-and-play connectivity, and parking lot structures – in a right-sized package for smaller or phased deployment scenarios.

Providing Fiber to Municipalities
The application that requires the greatest breadth of fiber distribution product choices is the municipality. Every municipal deployment is unique for a lot of reasons, and nobody wants to pay for equipment that is way too large for an application or is too small to allow for future growth. Municipalities can be comprised of MDUs, urban areas, rural areas, and everything in between. In other words, there will be an array of fiber distribution equipment for large, medium and small fiber counts – all in the same FTTP network.

Municipal governments must consider what is best for their current citizens as well as new business they hope to attract. Therefore, the network engineering requires extensive planning, usually with an outside engineering firm exploring what technologies and equipment make sense for the community's specific needs.

Municipal FTTP deployments are increasing as the need to be competitive drives the demand for the latest and greatest broadband capabilities. Many cities have incumbent providers who may not be willing to deploy fiber to improve their offerings. So to entice new business revenues, the municipality will decide to overlay existing infrastructure with a state-of-the-art broadband network.

As municipalities across the country successfully deploy FTTP networks, the need for fiber distribution equipment that addresses every deployment scenario will drive new innovation among vendors. Right-sized solutions will enable service providers and municipalities to extend fiber's reach into every deployment situation.

Whether pushing optical fiber into hundreds of living rooms in one MDU, connecting hundreds of single homes in a large housing development, or a combination of both within a municipality, right-sizing the fiber distribution equipment for each job is an important consideration. The FDH, whether high density, low density or low profile, should always include the necessary features of easy access, fast service turn-up, scalability options, and overall efficiency and reliability.

It's worth noting that one overall consideration in selecting and deploying FDH equipment is fiber management and slack storage capabilities. Proper fiber management techniques are important elements that, if adhered to, can eliminate many potential problems throughout the life of the network. Selecting the right-sized equipment that provides the same installation and operation benefits will increase the rate at which service providers can leverage every market opportunity.

About the Author
Jonathon Pearson is the marketing manager for carrier solutions at ADC, headquartered in Eden Prairie, Minn. He has 11 years of experience in marketing and product management. For more information, visit: www.adc.com.

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