Survivable Lightpath Provisioning in WDM Mesh Networks Under Shared Path Protection and Signal Quality Constraints

This paper addresses the problem of survivable lightpath provisioning in wavelength-division-multiplexing (WDM) mesh networks, taking into consideration optical-layer protection and some realistic optical signal quality constraints. The investigated networks use sparsely placed optical–electrical–optical (O/E/O) modules for regeneration and wavelength conversion. Given a fixed network topology with a number of sparsely placed O/E/O modules and a set of connection requests, a pair of link-disjoint lightpaths is established for each connection. Due to physical impairments and wavelength continuity, both the working and protection lightpaths need to be regenerated at some intermediate nodes to overcome signal quality degradation and wavelength contention. In the present paper, resource-efficient provisioning solutions are achieved with the objective of maximizing resource sharing. The authors propose a resource-sharing scheme that supports three kinds of resource-sharing scenarios, including a conventional wavelength-link sharing scenario, which shares wavelength links between protection lightpaths, and two new scenarios, which share O/E/O modules between protection lightpaths and between working and protection lightpaths. An integer linear programming (ILP)-based solution approach is used to find optimal solutions. The authors also propose a local optimization heuristic approach and a tabu search heuristic approach to solve this problem for real-world, large mesh networks. Numerical results show that our solution approaches work well under a variety of network settings and achieves a high level of resource-sharing rates (over 60% for O/E/O modules and over 30% for wavelength links), which translate into great savings in network costs.

Using Nebraska's Beginning Farmer Tax Credit Program

Many farm or ranch families that are attempting to bring a son or daughter back into their business experience a strain on the cash flow. Recent changes to Nebraska's Beginning Farmer Tax Credit Program provide an attractive incentive that can be very beneficial to those families. Regulation changes made in 2008 now allow parents to rent agricultural assets to their own children.

Using Nebraska’s Beginning Farmer Tax Credit Program

Many farm or ranch families that are attempting to bring a son or daughter back into their business experience a strain on the cash flow. After all, a business that has been providing enough income for one family to live on, must now not only generate adequate income for the parents living expenses, but also attempt to provide enough income for a second family, the successor. Recent changes to Nebraska’s Beginning Farmer Tax Credit Program provide an attractive incentive that can be very beneficial for family farming/ranching operations that are trying to bring a family member back into their business. Regulation changes made in 2008 now allow parents to rent agricultural assets to their own children.