arXiv subjects
Publications and source records attributed to Pallavi Athe.
Optical networks play a crucial role in todays digital topography, enabling the high-speed and reliable transmission of vast amounts of data over optical fibre for long distances. This paper provides an overview of optical networks, especially emphasising on their evolution with time.
Pre-configured cycle (p-Cycle) method has been studied in literature extensively for optical network protection. A large p-cycle has high capacity efficiency and can protect a large number of nodes against the single link failure scenarios. All the links protected by such a p-cycle lose protection when the p-cycle is consumed to restore traffic after a failure. As the probability of multiple link failure is high for a large network, it also means that with higher probability, on the second failure, protection may not be there for the failed link. Thus, if the number of links protected by a p-cycle is large, it makes the network unprotected with high probability on the advent of the second failure. In this paper, we study the impact zone due to a first link failure in the various configurations of the p-cycles. The study gives insight into how to choose the p-cycle configuration to reduce the impact zone while using minimum spare capacity. We propose few methods and compare them to show how the impact zone analysis can be used to improve the fault tolerance in an optical network.
In this letter, we investigate survivability in optical networks for protection from two simultaneous link failures. Failure probability of two links with overlapping protection can be high if these links are geographically close. In a network with deterministic single link protection, simultaneous failure of two links may lead to partial or full loss of traffic on the failed links. Two link failure protection will make the network more resilient by protecting double failures having overlapping protection. A method for achieving double fault tolerance is double cycle method (DB); it uses two pre-configured cycles (p-cycles) to protect a link. Single p-cycle (SG) method, which uses one p-cycle to protect a link from two simultaneous link failure is introduced in this letter. Integer linear programs (ILP) are formulated for the SG method as well as DB method. It has been observed that the SG method provides a solution to bigger networks with lesser computational resources as compared to the DB method.