Cooperative clustered architecture and resource reservation for OBS networks

Resource contention is a major concern in Optical Burst Switching networks that leads to relatively high burst loss probability. This article presents a clustered architecture for OBS networks, called Cooperative Clustered Optical Burst Switching (C
₂
OBS) network architecture. In this architecture, the network is divided in overlapping zones/clusters with a zone/cluster head having the knowledge of available resources within the zone called Zonal Base (ZB) and maintains a short resource usage history called Short History Base (SHB). A resource reservation strategy for the proposed Cooperative Clustered OBS network architecture (C
₂
OBS-RR) is also presented which is centralized within the zone and distributed in the overall network, for combining the benefits of both the centralized and the distributed resource reservation schemes. This novel approach uses the local state of the resource availability within the zone (ZB) so that the bursts originating at the ingress nodes in the same part of network having been assigned the same wavelength, can be assigned different time offsets. This will proactively reduce the probability of contention at the intermediate nodes within a zone and is expected to significantly reduce the overall network burst loss probability. For illustration purpose, the proposed C
₂
OBS architecture has been applied to the European Optical Network.