Choosing the right FTTH architecture for your network

Choosing the right architecture for your FTTH network is essential. Your network’s design has a major impact on both deployment costs and network performance.

There are several primary types of architecture, each with its own advantages and disadvantages:

• Centralized split
• Distributed split
• Star architecture
• Daisy-chaining

In this article, we briefly describe each network design approach so that you can make an educated decision on what’s best for your clients.

Centralized split

Centralized split architectures are one of the most commonly used by network operators for initial deployments.

The approach relies on centrally located single-stage splitters, which enables flexibility when it comes to managing subscribers and equipment. Typically, centralized architectures use a 1x32 splitter that is connected directly to a GPON central office-based optical line terminal on one side. On the other side, 32 individual fibers are routed to provide connectivity to unique subscribers through splice ports and distribution panels.

One downside of centralized split architectures is the high deployment costs on a per-home basis. In addition, setting up centralized architectures can take longer than other approaches as more fibers have to be routed all the way to subscriber homes.

Distributed split

Distributed split architectures rely on several cascading stages to distribute digital data from a central office. This approach is often less CapEx intensive and is easier to deploy as key network components don’t have to support as many fibers at once.

For example, a 1x4 splitter may be connected directly to the central office instead of a 1x32 splitter. Then, the four fibers leaving the 1x4 splitter would each go through a 1x8 splitter, thus creating 32 unique subscriber routes. Overall, this reduces the amount of fiber needed, as well as increases the capacity at fiber distribution hubs as they don’t have to support nearly as many fibers simultaneously.

Two limitations of distributed split architectures are that they are less flexible and have fewer monitoring capabilities built into the network. It can be harder to reroute services given the cascading nature of these networks.

Star architecture

Star architectures are the most efficient network design from a splicing perspective as cables are all pre-terminated and pulled back to a central location. These networks can use multi-port service terminals in order to avoid any splicing at distribution points.

This approach can be combined with both the centralized and distributed architecture approaches depending on your needs as an operator. While star architectures reduce the amount of splicing needed to deploy a network, they do require much more cable, which means that installation labor costs are often higher.

Daisy-chaining

One of the fastest deployment approaches is daisy-chaining, which only requires the use of one cable that passes through a number of fiber access terminals. As with star architectures, daisy-chaining can be used in conjunction with the centralized and distributed split approaches.

From a cost perspective, daisy chaining is highly efficient. Fewer materials and less labor are required overall to deploy networks in this way. On the downside, daisy-chaining may require specialized splicing, which can drive up costs.

FTTH architecture - Making the right decision

Ultimately, your FTTH network architecture will depend on a variety of factors, including the skill of your labor force, the geography of your local market, anticipated future growth, and how you want to deploy your capital.

Additionally, the density of your customer base is also a major deciding factor. In urban environments, distributed split architectures tend to be the best for quickly scaling and deploying connectivity for many subscribers. On the other hand, the flexibility that comes with centralized splits can be better for rural, less populated areas.

By understanding the different network design approaches, you can make a well-informed decision on which architecture best suits your needs.

With IQGeo's Network Manager Telecom, you have access to a sophisticated software-based platform that can be used to plan and design superior FTTH networks. To learn more, book a demo today.