Sparsely hubbed light-trail grooming networks

Recently, a new architecture called light-trails has been proposed that provides a novel control and management solution to address IP-centric issues at the optical layer. By inclusion of simple hardware that performs drop and continue functionality, overlaid with a light-weight control protocol, light-trails enable efficient sharing of network resources, improve bandwidth utilization and minimize network costs. Due to power budget constraints in such networks, it may not always be possible to have end to end communication in pure optical domain and requests may be required to traverse multiple intermediate transit points called hub nodes before reaching the final destination. The hub nodes need to be equipped with special hardware for switching and grooming connections. We investigate the problem of designing networks where such hubs are sparsely located. We show through our simulation results that by carefully designing heuristics for hub node placement and trail routing, it is possible to achieve high throughput with minimal number of hub nodes

Sparsely hubbed light-trail grooming networks

Recently, a new architecture called light-trails has been proposed that provides a novel control and management solution to address IP-centric issues at the optical layer. By inclusion of simple hardware that performs drop and continue functionality, overlaid with a light-weight control protocol, light-trails enable efficient sharing of network resources, improve bandwidth utilization and minimize network costs. Due to power budget constraints in such networks, it may not always be possible to have end to end communication in pure optical domain and requests may be required to traverse multiple intermediate transit points called hub nodes before reaching the final destination. The hub nodes need to be equipped with special hardware for switching and grooming connections. We investigate the problem of designing networks where such hubs are sparsely located. We show through our simulation results that by carefully designing heuristics for hub node placement and trail routing, it is possible to achieve high throughput with minimal number of hub nodes.This is a manuscript of a proceeding published as Balasubramanian, Srivatsan, Arun K. Somani, and Ahmed E. Kamal. "Sparsely hubbed light-trail grooming networks." In Proceedings. 14th International Conference on Computer Communications and Networks, 2005. ICCCN 2005., pp. 249-254. IEEE, 2005. DOI: 10.1109/ICCCN.2005.1523860. Posted with permission.</p

Cost-effective routing in wavelength division multiplexing (WDM) optical networks using super lightpaths

Cataloged from PDF version of article.In this study, we analyze the routing and wavelength assignment problem for one of the most recent applications of wavelength division multiplexing (WDM) networks, namely super lightpaths. We assume that the traffic is static and each node has the wavelength conversion capability. We try to determine the number of fibers to open for use on each physical link and the routing of the given traffic through super lightpaths so as to minimize the network cost, composed of fiber and wavelength usage components. The problem is proved to be NP-Hard and an integer linear program is proposed as an exact methodology to solve the problem for small scale networks. For larger network sizes, different heuristic approaches are developed. To evaluate the quality of the heuristic solutions, where optimal values are not available, the LP relaxation of the proposed model is strengthened through the use of valid inequalities. The heuristics are tested on a large set of varying network topologies and demand patterns. In terms of the deviation from lower bounds, the heuristic solutions attained are promising.Yalçın, BurakhanM.S