Exploiting SDN for integrating green TWDM-PONS and metro networks preserving end-to-end delay

In time and wavelength division multiplexed (TWDM) passive optical networks (PONs), energy efficiency can be traded with increased average frame delay. However, because some IP services have strict end-to-end delay requirements, such increased delay must be compensated in other network segments. To achieve such compensation, an interaction between control and management planes of different network segments is required. So far, such interaction could be achieved only by custom interfaces at the border of each network segment. Recently, software defined networking (SDN) has emerged as a de facto standard to provide a versatile control and management plane for any network segment. This paper proposes and successfully demonstrates an aggregation node based on a lightweight SDN solution scaled to operate as an intranode controller. The node connects a TWDM-PON, which implements an optical line terminalenergy efficient scheme basedondynamic bandwidth andwavelength allocation, and ametro/aggregationnetworkbasedonOpenFlowswitches. Resultsshowthat sleepmode inTWDM-PONcould increase the traffic delayby hundredsofmicroseconds,but,byprioritizingsuchtraffic in the metro network, the delay experienced by it in the metro segment is reduced by at least the same amount. Thus the end-to-end delay is maintained.