att_abstract={{The advent of colorless and non-directional reconfigurable
optical-add-drop multiplexers (ROADMs) will enable
flexible pre-deployment of optoelectronic regenerators in future
optical networks. Compared to the current practice of installing
regenerators only when a circuit needs them, pre-deployment
will allow service providers to achieve rapid provisioning and
restoration. The pre-deployed regenerators should be concentrated
in a selected subset of ROADM sites in order to attain high
utilization and to reduce operational costs. We prove that the
resulting optimization problem is NP-hard and present an efficient
heuristic for this problem that takes into account both the cost of
individual circuits (regenerator cost and transmission line system
cost) and the probability of a given circuit request, as well as
the number of regenerator sites. We provide various methods
to reduce the number of regenerator sites, if low probability
demands are allowed to have slightly costlier paths. Specific
network examples show that the proposed heuristic has near
optimal performance under most studied scenarios. We present
results for several different cost models. We have also evaluated
the heuristic for survivable optical networks, in which a second,
disjoint path must be supported for each circuit.}},
	att_authors={rs5419, ac2182, mf2182, gl1464, sw1213, wz1750, rd2518, pm1519},
	att_copyright_notice={{This version of the work is reprinted here with permission of IEEE for your personal use. Not for redistribution. The definitive version was published in 2012. {{, 2013-03-04}}
	att_tags={ROADM,  regenerator placement,  network optimization, all-optical networks},
	author={Rakesh Sinha and Angela Chiu and Mark Feuer and Guangzhi Li and Sheryl Woodward and Weiyi Zhang and Balagangadhar G Bathula and Keren Bergman and Robert Doverspike and Peter Magill},
	institution={{DRCN 2013}},
	title={{Cost Optimization Using Regenerator Site
Concentration and Routing in ROADM Networks}},