Advance reservation for periodic transfers with flexibility

Abstract

Wavelength Division Multiplexing (WDM) technology enables a lightpath to carry tens of gigabits of data per second. However, many applications may require an optical connection for only short periods of time, and leasing a lightpath full time for that purpose may be too costly. We consider a single WDM link that is time shared by a given collection of optical connections. The system is time slotted with period T. Each optical connection has a prescribed duration per time period. In addition, it has a prescribed time window within which its duration may begin. The size of the window is the amount of time flexibility there is to schedule the optical connection. The problem considered is to set up the optical connections. Formulas are provided to show the relationship between wavelength efficiency and the "burstiness" and time flexibility of the connections. In addition, a few heuristic algorithms are presented that perform better than simple scheduling rules of a packet-switched network, under simulations for randomly generated optical connections.