Traffic over the internet is becoming more and more congested. When routing one point on the world wide web to another, internet service providers often want to find the shortest path between them in an effort to optimize data transfer rates. However this often results in many signals being routed through the same path and causes congestion. In an effort to ease the congestion, sometimes users are routed through a different, longer path but with less congestion. This trade off is the process of optical routing and flow control and often will result in faster data transfer rates.

The process of routing and rerouting data based on transfer rates that depend on traffic is similar to network theory on finding Nash Equilibria between multiple nodes in a graph. Applying basic network theory to complicated things such as the internet and web traffic routing can often result in more efficient and well connected graphs.

http://en.wikipedia.org/wiki/Optical_IP_Switching