Because of advancements in xWDM it is not limited. By replacing networking equipment (0.000001% of total cost) you can x10, x100, and more the bandwidth on an e

Because of advancements in xWDM it is not limited. By replacing networking equipment (0.000001% of total cost) you can x10, x100, and more the bandwidth on an existing cable. The same (single mode) optical cable that was once capable of running 2mbps is now able to run 400 * 100Gbit. Now wireless is starting to repeat this evolution. This is one of the reasons for the old joke: "Do you know how to amass a small fortune in Telecom?" "Start with a big fortune"