parts of the network are driven daily to guarantee reliability and proactively fix problems. They also offer colocation facilities for servers at Chicago, Carteret, and Cleveland, all along the line. Their estimated roundtrip time along the dark fiber line (from Chicago to Carteret) is 13 milliseconds. Their wave service lines promise roundtrip times of about 14.1-14.2 milliseconds, down from about 14.6 milliseconds in 2011. According to a WIRED article, the estimated roundtrip time for an ordinary cable is 14.5 milliseconds, giving users of Spread Networks a slight advantage. However, because glass has a higher refractive index than air (about 1.5 compared to about 1), the roundtrip time for fiber optic cable transmission is 50% more than that for transmission through the air. Some companies, such as McKay Brothers, Metrorede and Tradeworx, are using air-based transmission to offer lower estimated roundtrip times (8.2 milliseconds and 8.5 milliseconds respectively) that are very close to the theoretical minimum possible (about 7.9-8 milliseconds). See also Flash Boys: A Wall Street Revolt by Michael Lewis The Hummingbird Project References External links Fiber-optic communications Internet technology companies of the United States 2017 mergers and acquisitions Financial technology companies