Agile bandwidth management techniques in slotted all-optical packet switched networks

The next generation metro network is most likely to be based on high-capacity agile all-optical networks. We consider a metro network architecture that consists of a number of buffer-less all-optical core switches, where a number of edge switches are connected to each core switch in an overlaid star topology. We would like to design potential candidates of resource-sharing schemes in such a network and evaluate their performances, where they guarantee to deliver optical packets to their destinations. The first scheme is reservation-based, in which decisions are made at each core switch so that collisions (and therefore loss) can be avoided through reservations. For this scheme, we have re-designed the BvN (Birkhoff von Neumann) scheduling algorithm to accommodate the asymmetric multi-fiber/multi-wavelength feature in star OPS. In the second scheme, distributed and independent decisions are made at edge switches, but we need to retransmit the traffic dropped at core switches in the optical domain. We also implement a hybrid case as the third scheme which combines the good attributes of both previous schemes. We have characterized and evaluated the performance of these resource-sharing schemes by various QoS measures such as delay and loss probabilities in edge switches. (C) 2009 Elsevier B.V. All rights reserved.