An Online Strategy for Service Degradation with Proportional QoS in Elastic Optical Networks

Elastic Optical Networks (EONs) represent a new approach for dealing with the enormous traffic demand in core networks as they can offer bandwidth granularities closer to those requested by the user and hence improve spectral utilization. In current literature there is a lack of dynamic strategies for service degradation which is a possible measure to address problems related to network congestion and consists in reducing the amount of resources provided. Since services of different classes can be requested, we propose in this paper an online strategy for service degradation using proportional Quality of Service (QoS). Our proposed strategy aims at minimizing the number of blocked requests due to lack of resources while provides throughput and delay guarantees for provisioned lightpaths. Thus, in order to quantify the impact of the degradation on the lightpaths we modeled source-destination pairs in an EON as a queuing system working under the Generalized Processor Sharing (GPS) service discipline with admission control of Leaky Bucket policy. The obtained results show that the proposed algorithm can reduce the blocking probability and give network operators more control between different degraded service classes.