QoS-aware protection in flexgrid optical networks

Abstract

Elastic optical networks generally rely on protection and restoration mechanisms to prevent the detrimental effect of fiber cuts. In particular, we investigate optical protection in flexgrid optical networks where the symbol rate is varied as a complementary approach to modulation format. We propose a novel protection scenario, whereby premium traffic survives cuts with just-enough bandwidth, which we call "quality-of-service-aware protection" (QoS-aware protection). The proposed mechanism exploits a variable baud rate transponder in order to reduce the spectrum occupancy of the protecting path and to ease the establishment of new traffic demands. Equipped with two lasers and optical switches, the QoS-aware node allows fast switching between different working and protecting bit rates. The two wavelengths also help to reduce the spectrum fragmentation. We compute typical spectral usage boosted by 80% to protect 25% of premium traffic with respect to current 1 + 1 protection. We demonstrate a field programmable gate array (FPGA)-based proof-of-concept node of QoS-aware protection that reconfigures in <2.8 ms. We program and select the ratio of premium versus best effort traffic as a tunable input parameter of the proof-of-concept.