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Telecommunications Basics Part 2: Anatomy of a Fiber Network

Updated: Dec 28, 2023

In part 1 of our Telecommunication Basics Series, we investigated the evolution of telecommunications networks. In part 2, we dive deeper into fiber technology, specifically the anatomy of a fiber network.

First, let’s establish that not all fiber networks are the same, and many networks are tailored to fit a specific area based on the geographical makeup, the number of customers, construction, etc. For example, a network that serves a Multi-Dwelling Unit (MDU) like an apartment building or dormitory would have a different arrangement than a network that operates in a rural area. It would also differ from a network primarily serving businesses in a densely packed area. Generally, the anatomy of most fiber networks will follow the basic framework outlined in this blog.

The following anatomy of a fiber network is based on a Passive Optical Network (PON) framework. PONs are a common type of network arrangement because they are efficient and low-cost compared to other setups. By utilizing multiple splitters to re-distribute signals, a network and its services can be shared with more customers more efficiently than other network arrangements. However, no matter their arrangement, Passive Optical Networks are made up of combinations of critical facilities, including Central Offices, Fiber Distribution Hubs, and Terminals.

CENTRAL OFFICES: A Central Office (CO) is the origin point of all fiber and copper networks. The CO is always where signals that are transmitted through the network start. These signals flow “downstream” from the CO to other facilities and eventually to individual customers. To continue our anatomy of a fiber network metaphor, if a fiber network were a nervous system, the CO would be its brain. You can’t have a network without a Central Office!

Fiber cables plugged into a switch port.
Anatomy of a Fiber Network

FIBER DISTRIBUTION HUBS: Fiber Distribution Hubs (FDHs) are another critical part of the anatomy of a fiber network. They usually contain a splitter that allows them to take in a lower fiber count from a CO and distribute a higher fiber count “downstream” towards customers. Every fiber optic cable has a “count”. This count will tell you how many individual fibers exist within a cable – which is imperative in determining how much data a network can handle transmitting and how many customers a network can serve.

TERMINALS: As you may recall from part one, a fiber network transmits data via light signals that travel through the glass fibers of a cable. Eventually, for the customer to use the data, these light signals need to be converted back into electrical signals by a terminal that internet-connected devices can use on the customer’s premises. This includes any devices that utilize the network: TVs, computers, phones, gaming consoles, etc. Suppose a CO is the starting point of the anatomy of a fiber network. In that case, terminals are the endpoint for the light signals traveling through the network. Each fiber stemming from a terminal is used by an individual residence/business to transmit their internet, TV, and voice data, so the more fibers a cable network has, the more customers it can support!

A city skyline at night with blue lines intersecting each other to illustrate internet connectivity.
Anatomy of a Fiber Network

Now, after reading through parts 1 and 2 of our guide to the basics of telecommunications, you have learned about the evolution of telecommunications networks and the anatomy of a fiber network! While this blog series is a great starting point, countless articles are online to deepen your understanding of telecommunications. Our blog page offers a wide selection of topics covering telecommunications, workplace culture, and more. Check out all our blogs to continue exploring the world of telecommunications!

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