Protected Working Groups-based Resilient Resource Provisioning in MCF-enabled SDM-EONs

Space Division Multiplexed- Elastic Optical Networks using Multicore Fibers are a promising and viable solution to meet the increasing heterogeneous bandwidth demands. The extra capacity gained due to spatial parameters in SDM-EONs could encounter detrimental losses if any link fails and timely restoration is not done. This paper proposes a Protected and Unprotected Working Core Groups assignment (PWCG/ UPWCG) scheme for differentiated connection requests in multicore fiber-enabled SDM-EONs. A PWCG is inherently protected by resources in a Dedicated Spare Core Group (DSCG). First, we divide the cores into three groups using traffic and crosstalk considerations. In the second step, we use the obtained core groups for resource provisioning in dynamic network scenarios. The effectiveness of our proposed technique is compared with a Link Disjoint Path Protection (LDPP) technique, and the simulation study verifies our assertions and the findings

Sub-Graph p-cycle formation for span failures in all-Optical Networks

p-Cycles offer ring-like switching speed and mesh-like spare capacity efficiency for protecting network against link failures. This makes them extremely efficient and effective protection technique. p-Cycles can also protect all the links in a network against simultaneous failures of multiple links. But it has been mostly studied for single link failure scenarios in the networks with the objective to minimize spare capacity under the condition of100% restorability. For large networks, use of p-cycles is difficult because their optimization requires an excessive amount of time as the number of variables in the corresponding Integer Linear Program (ILP) increase with the increase in the network size. In a real-time network situation,setting up a highly efficient protection in a short time is essential.Thus, we introduce a network sub-graphing approach, in which a network is segmented into smaller parts based on certain network attributes. Then, an optimal solution is found for each sub-graph. Finally, the solutions for all the sub-graphs is combined to get a sub-optimal solution for the whole network. We achieved better computational efficiency at the expense of marginal spare capacity increases with this approach

Availability-Aware Dynamic RSA with Protection using Consecutive Sub-Channels

Flexible grid Optical Networks provide efficient spectrum utilization by employing the mechanisms to provide flexibility in the optical channel (spectrum slot) sizes. One of the research problems in Flexible grid Optical Networks is their survivability against failure. On the other hand, p-Cycles have not found practical use due to the significant compute time required for finding optimal configuration for the size of networks seen in real-life. Therefore, for real-time scenarios, we can write heuristics which can assign protection to the new working paths without disturbing the existing traffic on all the other routes in flexible grid networks. The provisioning of protection to each link or path of the lightpath requests can be done using Dynamic Cycles (D-Cycles) or Dynamic Shared Backup Resource Protection (D-SBRP). However, protecting each link or path can lead to the wastage of the resources in the network

A Vectored Fragmentation Metric for Elastic Optical Networks

When circuits are set up and dismantled dynamically in elastic optical networks, spectrum tends to become fragmented in the fiber links. The fragmentation limits the available path choices and may lead to significant blocking of connection requests. There are two types of fragmentation in the network spectrum in the links due to contiguity constraints and over the paths due to continuity. Study of fragmentation and its management is essential to operate the networks efficiently. This paper proposes a vectored fragmentation metric for characterizing the fragmentation, which covers both types of fragmentation. We discuss the characteristics of this metric in both transient and steady-state of the dynamic network. We also test the proposed metric for connection requests granularity range, arrival rates and holding times, to establish functionality of this metric. We also compare the link-based fragmentation metric with our Vectored Fragmentation Metric to understand the better representation.Comment: 11 page

Challenge and Response in the Indus Basin

The authors examine the complex history of the development of the Indus Basin and the challenges faced by Pakistan during the evolution of the Indus Basin Irrigation System and the country\u27s responses to date. The Indus river system must meet the multiple needs of agriculture, energy and flood security. Pakistan\u27s constitutional structure, in which the federation shares overall responsibility for the operation of the Indus with the provinces, poses unique management and implementation challenges. What are the institutional arrangements Pakistan needs to address the challenges to the Indus Waters Treaty it signed with India in 1960? How is the country going to regulate the use of over-abstraction in the basin with the increased reliance on groundwater to maintain agricultural productivity? What are the institutional mechanisms in place to manage increased river flow variations from glacial melt as a result of climate change and for coping with devastating floods? At the same time, is the country maintaining adequate environmental flows to its delta? Provincial mistrust and a lack of institutional capacity underpins the history of the Indus in Pakistan with the Interprovincial Water Accord 1991 serving as a ray of hope on which to build a new institutional architecture of cooperation

Challenge and Response in the Indus Basin

The authors examine the complex history of the development of the Indus Basin and the challenges faced by Pakistan during the evolution of the Indus Basin Irrigation System and the country\u27s responses to date. The Indus river system must meet the multiple needs of agriculture, energy and flood security. Pakistan\u27s constitutional structure, in which the federation shares overall responsibility for the operation of the Indus with the provinces, poses unique management and implementation challenges. What are the institutional arrangements Pakistan needs to address the challenges to the Indus Waters Treaty it signed with India in 1960? How is the country going to regulate the use of over-abstraction in the basin with the increased reliance on groundwater to maintain agricultural productivity? What are the institutional mechanisms in place to manage increased river flow variations from glacial melt as a result of climate change and for coping with devastating floods? At the same time, is the country maintaining adequate environmental flows to its delta? Provincial mistrust and a lack of institutional capacity underpins the history of the Indus in Pakistan with the Interprovincial Water Accord 1991 serving as a ray of hope on which to build a new institutional architecture of cooperation