Dark Fiber vs Lit Fiber WAN Services - Full Span Solutions

There are many different types of Wide Area Network (WAN) services available on the market today. The two most fundamental service categories are dark and lit fiber services. Both have their own pros and cons, but these differences typically help narrow down the options fairly quickly. In this blog post, we will compare and contrast dark fiber vs lit fiber WAN services, so that you can make an informed decision about which one is best for your business!

Dark Fiber vs Lit Fiber Service Availability

Lit fiber services are significantly more available than dark fiber services. Dark Fiber requires an end-to-end fiber path while lit services can make many hops through active equipment and even span multiple service provider networks. This makes dark fiber a better choice for businesses and ISPs that need large amounts of bandwidth in a relatively small geographic area. This area, of course, needs to be completely covered by that single service provider who can deliver the dark fiber service end to end. Lit services on the other hand can be built with last-mile connectivity from a separate provider on each end if required.

Types of Services

Point to Point

Dark Fiber is always a point-to-point connection between two locations. It can be used to connect commercial buildings, data centers, remote network cabinets, and wireless tower sites. The customer will provide every active network component to drive this data service. The service provider will provide repair services but because they have no real visibility of the circuit itself they do not provide monitoring and other advanced technical services.

Lit services can be provided as point-to-point services as well. A lit service does not require an end-to-end fiber path, however. The data signals can travel over multiple active equipment hops and even span multiple service provider networks if required. This type of connectivity often provides the best combination of flexibility and price.

Point to Multi-Point

Dark Fiber is a point-to-point connection so it cannot be used for point-to-multi-point connectivity. A point-to-multi-point connection is what you would order to connect to multiple locations to a single hub location. Dark Fiber is not an option for this type of service. Instead, service providers will build ethernet-based services over their existing networks to implement the service in full. Point to multipoint services go by several names such as E-LAN and Virtual Private LAN Services (VPLS) amount others.

Capacity / Bandwidth

Dark Fiber has the ability to support very high bandwidth capacity because it is an end-to-end connection with no active equipment in the middle. Dark Fiber can support data rates up to 100 Gbps and beyond. Really the limiting factor is the equipment the customer puts on either end. Lit fiber services also have the ability to support high bandwidth capacities, but because they use active equipment along the path that bandwidth may come at a higher cost or with some limitations.


Dark Fiber can span only medium distances, up to a few dozen Kilometers, without active repeater equipment along the path. A service provider offering a lit service will already have this network infrastructure in place. Your WAN service will ride over this existing network with modulation technology to optimize the link utilization from city to city or even further making the possibilities nearly endless.


Of course, a very important aspect in deciding which way to go is the cost. With dark fiber services, it can be difficult to price generally because of a number of factors. In this case, let’s assume the connectivity is across town between data centers. This might be fairly inexpensive. There is no active equipment for the service provider to supply and the fiber route itself is easy to maintain. Alternatively lit services in data centers are typically the best buy for the money as well. At Sure Fiber we typically suggest letting the technical and business requirements drive the conversation first and often this helps determine what solution to focus on.

How to Order Dark Fiber or Lit Fiber Services?

At Sure Fiber, we are here to help make sense of the options on your behalf. No two networks are the same and seldom are customer requirements. To work with our team for either dark or lit WAN services get connected with us! Share your project details and our team of experts will help evaluate service provider availability, review fiber route maps and pull in our service provider partners to help deliver the best solution for your organization.  To request a consultation around either of these services be sure to connect with us here!