Dynamic Management of Forwarding Rules in a T-SDN Architecture with Energy and Bandwidth Constraints

Telecom operators recently started to integrate Software-Defined Networking facilities for controlling and managing their optical transport networks. Here, the management of forwarding rules into the resulting Transport Software-Defined Networking (T-SDN) architecture has to be addressed by taking into account the energy and quality of service requirements. While the most of works in the literature studied these aspects separately, the few contributions that simultaneously take care of energy and quality of service requirements present latency, scalability, or control communication issues. Starting from these considerations, this paper formulates a novel methodology for the dynamic and reactive management of forwarding rules in a (potentially large-scale) T-SDN network, based on the knowledge of network topology, the power consumption of optical switches, the expected volume of traffic, and the variability of the actual traffic load. First, the expected volume of traffic and the estimated power consumption of optical switches are exploited to select the minimum number of nodes and transport links to activate, which enable the communication among any source and destination pairs declared within a given traffic matrix. Then, the bandwidth consumption of activated transport links is periodically monitored by a centralized controller and, in case of congestion, a new set of optical switches and transport links are quickly turned on for addressing the growth of the traffic load. The effectiveness of the proposed approach has been investigated through experimental tests and compared against another reference scheme which considers the energy issue only. Obtained results demonstrate its ability to offer higher levels of quality of service to end-users, at the expense of a limited decrease of the registered energy-saving.