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Designing an Optical Island in the Core Network: From Routing to Spectrum Allocation


Deepak Mehta, Barry O'Sullivan, Cemalettin Ozturk, Luis Quesada, Helmut Simonis

Publication Type: 
Refereed Conference Meeting Proceeding
We consider a network design problem arising in the development of an all-optical future generation Internet network called a flex-grid. An optical island is a set of core nodes that can be fully interconnected by transparent wavelength routes. We present a mathematical model for finding an optimal optical island, show that it is an NP- hard problem, and present a decomposition for solving it. In a first phase, we choose network links and route the traffic over the resulting network. In the second phase, we allocate the light-paths associated with the traffic requests to individual fibres and spectrum segments on the fibres. This so-called routing and spectrum assignment (RSA) problem is a generalisation of the well-known routing and wavelength assignment problem (RWA) of conventional optical networks. Flex-grid optical networks allow us to bundle higher capacity connection requests by allocating channels in a number of contiguous frequency slots, providing increased throughput, as long as the connection length is below technological limits. We solve the first part of the decomposition with a large neighborhood search, and the second with a CP model using a single GEOST global constraint. Results for Ireland and Italy show that solutions of high quality can be found by this decomposition.
Conference Name: 
The IEEE International Conference on Tools with Artificial Intelligence - ICTAI 2014
2014 IEEE 26th International Conference on Tools with Artificial Intelligence
Digital Object Identifer (DOI): 
Publication Date: 
Conference Location: 
National University of Ireland, Cork (UCC)
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