Optical Power Control in GMPLS Control Plane

Abstract

International audienceThe exponential traffic growth in optical networks has triggered the evolution from Fixed-Grid to Flex-Grid technology. This evolution allows better spectral efficiency and spectrum usage over current optical networks in order to facilitate huge dynamic traffic demands. The promise of Flex-Grid technology in terms of increasing the number of optical channels established over optical links may however not be sustainable because of the associated increase in optical amplification power. In this work, we detail a power control process that takes advantage of link optical power and channel optical signal to noise ratio (OSNR) margins to allow network operators to support this optical power increase while maintaining the use of legacy optical amplifiers. New GMPLS protocol extensions are proposed to integrate the optical power control process in the control plane. The performance of the process is evaluated in terms of the blocking ratio and network throughput over Fixed-Grid and Flex-Grid networks. Results show that controlling optical power benefits from the Flex-Grid technology in terms of spectrum and capacity gain and reduces optical connection blocking

Power-Aware Regeneration Algorithm in Flex-grid Networks

“…In fact, this goal can be achieved through maximizing the OSN R margin of the candidate lightpath over the segment containing the optical link having the highest power level. This link is identified through its power ratio (W l = P real,l /P max,l ), which is equal to the current aggregated link power (P real,l ) divided by the maximum power level (P max,l ) allowed over the link l (as defined by the link design 5 ). Figure 1 shows the execution result of the traditional regeneration placement algorithm 8 (TR) for a candidate optical channel between node A and F. In this case, the regeneration sites (i.e., C and E) are computed by exploiting the maximum reach of the optical transceiver, guaranteeing minimum number of regeneration sites (i.e., minimum cost).…”

“…In order to evaluate the PAR algorithm, we improved our distributed GMPLS-based network simulator 5 to take into account of optical regeneration. Simulations are performed over the European backbone network of Figure 3, considering the same link design (80 channels of 50 GHz per link over a fixed-grid network infrastructure), filtering penalties, channels types and minimum acceptable OSNR (15 dB) as in 5 .…”

“…Simulations are performed over the European backbone network of Figure 3, considering the same link design (80 channels of 50 GHz per link over a fixed-grid network infrastructure), filtering penalties, channels types and minimum acceptable OSNR (15 dB) as in 5 . In order to simplify the analysis of results, only 100 Gbit/s optical channels (occupying 37.5 GHz each) are established in simulated scenarios.…”

“…This adaptation is possible by converting the OSNR margins (OSN R margin ) into optical power attenuation over optical links 1,4 . However, this power saturation can always arise over highly loaded links as demonstrated in 5 , especially when there is no sufficient exploitable OSNR margins.…”

“…In this work, we consider only the channel power adaptation, in order to reduce the power level over highly loaded links and avoid power saturation. The higher is the OSN R margin , the higher is the power attenuation that can be applied to an optical channel 5 .…”