Comparison of Switching Cost for Ring Optical Backbone Networks

A point-to-point wavelength division multiplexed (WDM) network is an optical network that uses electronic routers in its nodes for switching. On the other hand, in an automatically switched optical network (ASON), the switching is done in optical domain. Electronic switching is more expensive than optical switching. Pass-through traffic, which is traffic that goes through a node without originating or terminating at that node, gives a measure of switching required in each node, and hence the cost of switching. In this paper, we derive expressions for pass-through traffic and switching cost for a ring topology. Using these expressions, we show that, in the worst case, electronic switching in a point-to-point WDM network is almost 36 times more expensive than the optical switching in an ASON.