Optimal Placement of Add/Drop Multiplexers: Static and Dynamic Models.

We study further a problem that has arisen recently in the design of telecommunications transmission networks at France Telecom. Given a set of centers in a city of conglomeration linked together on a ring architecture, given the expected demands between the centers and an essentially unlimited availability of rings of fixed capacity on the network, assign demand pairs and corresponding add/drop multiplexers to the rings so as to satisfy the demands and minimize the number of "costly" multiplexers installed.