An efficient method to estimate transponder count in multi-layer transport networks

The cost of a multi-layer transport network comprising a WDM layer and an SDH/SONET/OTN layer is in many cases dominated by the number of electro-optical converters (transponders) in the network. An efficient method to estimate the transponder count required in multi-layer networks, consisting of opaque, transparent, or hybrid nodes, is proposed. The method is based on analytical approximations which take only a small number of characteristic network topology and traffic parameters as input and are therefore easy to apply to many network scenarios. It is shown that the approximations match the results achieved by optimisation algorithms with very good accuracy. This enables comparison of network architectures and transponder technologies in a very general way. As an example for the application to a relevant practical issue, the paper analyses cost efficiency of a 40G transponder deployment.