Extending the QoS provisioning in GRNET

This work presents the extension of QoS provisioning in GRNET, so as to include a ldquosecond chancerdquo mechanism for rejected premium-traffic requests. Regularly, accepted requests can be satisfied even if there is a single failure in the network and no specific path is allocated within the network core. The extended mechanism allows for rejected requests to be reconsidered for acceptance over a specific path, under the condition that if a failure occurs in this path, then the corresponding traffic will lose the premium handling and will be then considered as best effort. The extended scheme allows for more flexibility and gives a balanced alternative to the ldquoeither full guarantees or no QoS at allrdquo situation of the existing scheme.