Reconfiguration of traffic grooming optical networks

Advances in optical data transmission and optical signal routing has caused wide expectation for optical networks to form tomorrow's backbone transport. One attractive feature of these networks is the ability to reconfigure the logical topology of the network seen by higher layers with comparative ease and speed by reconfiguring optical switches, without the need to modify the physical topology of the network. On the other hand, with the current mismatch of bandwidth available from individual wavelength channels and typical bandwidth demands, it is also widely recognized that grooming of subwavelength traffic into the full-wavelength channels is an indispensable component of optical network design. The topic of reconfiguration in optical networks that carry subwavelength traffic has received comparatively little attention. In this paper we consider this problem. Our main contributions are as follows. We discuss the common basis on which grooming effectiveness and reconfiguration efficiency can be considered, and develop a reconfiguration cost function in keeping with this consideration. We formulate the joint problem of reconfiguration and grooming precisely, and offer a heuristic as well as an exact solution method to solve this problem. In offering numerical simulation results for our algorithms, we make the important observation that a disjoint sequential consideration of the two problems leads to solutions that are very inefficient in the joint sense.