Improved EDF-based management of the setup of connections in opaque and transparent optical networks

The need to support the diverse quality-of-service (QoS) requirements of the ever-emerging Internet applications is a major challenge for optical network operators. This paper tackles such a challenge through the definition of a QoS-aware optical connection setup management scheme. The proposed scheme utilizes the Earliest Deadline First (EDF) queueing discipline to schedule the setup of optical connections that cannot be established due to lack of optical resources. The EDF-based approach aims at minimizing blocking probability while realizing QoS differentiation. Blocking probability reduction is realized through the insertion of blocked connection requests into a queue giving them thus a second chance with respect to network access. QoS differentiation on the other hand is achieved as follows. The blocked connection requests are ranked in the EDF queue according to their connection setup requirements, which are viewed as deadlines during connection setup. In this way, pending connection requests having shorter setup time requirements are guaranteed to experience better QoS compared to the ones having longer setup time requirements. The performance of the EDF-based strategy is analyzed through extensive simulations in the context of both opaque and transparent NSFNET network topologies. The reported results show that the proposed strategy yields remarkable reduction in terms of blocking probability while effecting QoS differentiation.