Some open issues in the optical networks control plane

The growth of bandwidth demand for data traffic drives the evolution of current transport networks towards the introduction of the automatic switched optical network (ASON). Introducing automatic switching capabilities in optical networks means designing and implementing control functionalities. Such functionalities are hosted at the network control plane, and mainly consist of providing signalling and routing mechanisms distributed throughout the network. The paper addresses some issues still under discussion on the definition of a suitable control plane for optical core networks. Specifically, we deal with the routing protocol, which defines the distribution of topology information, the path selection and the association of nodes in a network; and with the routing mechanism, which allows selection of the path according to the attributes of connection requests and the available resources in the network. We also deal with the traffic engineering strategies used to optimise the use of these resources and give a quick view of future trends in optical networks.