In this paper we propose a cycle redundancy technique that provides optical networks almost fault-tolerant pointto-point and multipoint-to-multipoint communications. The technique more importantly is shown to approximately halve the necessary light-trail resources in the network while maintaining the fault-tolerance and dependability expected from cycle-based routing.For efficiency and distributed control, it is common in distributed systems and algorithms to group nodes into intersecting sets referred to as quorum sets. Optimal communication quorum sets forming optical cycles based on light-trails have been shown to flexibly and efficiently route both point-to-point and multipoint-to-multipoint traffic requests. Commonly cycle routing techniques will use pairs of cycles to achieve both routing and faulttolerance, which uses substantial resources and creates the potential for underutilization. Instead, we intentionally utilize redundancy within the quorum cycles for fault-tolerance such that almost every point-to-point communication occurs in more than one cycle. The result is a set of cycles with 96.60 -99.37% fault coverage, while using 42.9 -47.18% fewer resources. Keywords: optical fiber networks, WDM networks, routing, fault tolerance, unicast, multicast communication
INTRODUCTIONWe developed a novel method to deliver almost fault-tolerant capabilities of cycles in an optical network while significantly reducing the resource utilization when compared to the state-of-art techniques. Cycle-based routing can satisfy both dynamic point-to-point and multi-point optical communications. Cycles are created using quorums of nodes. Within a cycle, multicasts to all nodes in that cycle is possible. The quorum intersection property and the use of cyclic quorums sets provide all of the unicast capabilities. Exploiting the same properties we can achieve efficient broadcasts with O(√ ) multicasts.Optical networks are depended upon for high speed communications in distributed algorithms, as much as they are needed for the arbitrary point-to-point communications. Failures within a network are to be expected and can happen as much as every couple days. Protecting against these optical circuit faults is critical and there are many different approaches depending on the network needs and individual circumstances.For efficiency and distributed control, it is common in distributed systems and algorithms to group nodes into intersecting sets referred to as quorum sets. Quorums sets for cycle-based routing to efficiently support arbitrary point-to-point and multi-point optical communication were first proposed in [1] with fault-tolerance analyzed in [2]. In this paper we apply the same established quorum set theory and add additional requirements to form suitable quorums for our optical network routing.The rest of the paper is organized as follows. Sections 2, and 3 establish the network model, node communication, and path routing / fault-tolerance. In Section 4, we discuss our application of the distributed efficiency of t...