A capacity correlation model for WDM networks with constrained grooming capabilities

Traffic grooming in optical networks is defined as the act of multiplexing, demultiplexing and switching lower rate traffic streams onto high capacity lightpaths. WDM networks with grooming capabilities can be classified into two basic types: constrained grooming networks, which perform grooming only at OADMs in the nodes and sparse grooming networks, which, in addition to grooming at OADMs, perform traffic stream switching between wavelengths at the nodes. In this paper, we propose a new capacity correlation model which takes into account the capacity distribution on the wavelength, the arrival rates of the calls of varying capacity, and the load correlation on neighbouring links to compute the blocking performance on a multi-hop single wavelength path. We also show that the capacity correlation model can be used to study the blocking performance of constrained grooming networks of arbitrary topologies. The results indicate that the capacity correlation model is more accurate than the link independence model proposed in Thiagarajan and Somani (2000)