A Transport-SDN Application for incremental on-line network optimization
07 May 2015
Today, off-line network planning tools are used to optimize transport networks from scratch. All established wavelength services are taken into account for optimization. Performing such optimization in an operational transport network may lead to a significant impact on the optical layer due to the rerouting of a large amount of wavelengths per link which requires massive adjustments of optical power levels. However, it would be beneficial to perform the optimization more closely interlinked to the network and its elements.
To implement an optimization application, which is also vendor-independent, an open control framework like Transport-SDN is particularly suitable. Our Transport-SDN optimization application runs on top of a SDN controller which - in turn - is communicating with the network elements. A demonstration environment has been developed to evaluate the feasibility and the benefits of such on-line network optimization.
The demonstrator comprises beside the application itself an Alcatel-Lucent Proof-of-Concept T-SDN controller as well as an emulated transport network. The current network topology and configuration are query results from the SDN controller and thus input parameters for our application. The application performs an incremental routing optimization which is aware of physical impairments of optical transmission. The goal of this incremental process is to affect only a very small number of wavelengths per iteration thus limiting the impact of wavelength rerouting on the photonic layer.
The optimization process, which can be controlled by the operator or can be run periodically in the background, determines inefficient routes and tries to find better alternatives. If a more efficient route was found, the new path information is posted to the SDN controller which has to implement the rerouting. Our application thus enables the permanent analysis of light path deployment in transport networks in order to increase resource utilization and reduce cost per service.
