Dark fiber is a relatively new term for a concept that is actually as old as networking itself, and that concept is the private network. Many people are familiar with the use of virtual private networking to provide secure and limited access to data, and with the concept of a hard-wired local area network that is secure to a single location and lightning fast within its own internal connections.
Dark fiber takes both of these ideas a step further, by laying hard fiber connections between buildings in various locations. This provides a secure private network, allowing organizations to utilize one hundred percent of their fiber bandwidth for interior operations, which makes it easier to perform data-intensive tasks over a widely distributed area. The infographic below, from Southern California's dark fiber provider Wilcon, has more details about how this exactly works.
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