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Cost is a major concern in telecom industry. Cost-efficient network design has been attracting the attention of network operators (NO). Wavelength-division multiplexing (WDM) optical technology is being widely deployed in telecom networks for their high capacity. Backbone telecom networks, which are mesh-connected, employ optical crossconnects (OXC) at switching nodes; and OXC deployments today are of the opaque (optical-electronic-optical, OEO) variety. In such a network, the number of OXC ports is a major portion of the cost of the switching equipment (not counting the cost of the transmission equipment, which is needed anyway independent of the switching equipment). In this work, we focus on a practical situation in which a bundle of ports are fabricated on a single blade, called a line card (LC). If we are restricted to using only bundles of ports per LC, this will impose an extra constraint on cost-efficient network design, especially for asymmetric traffic between node pairs and arbitrary network topologies. Our design relies on a two-step approach using two algorithms whose objective is to reduce the number of LCs (ports). First, we route traffic connections on low-cost paths where cost depends on how much resources are needed to support the connection. The second step is a reassignment step, which tries to re-optimize the outcome of the first step. Simulation was conducted on a sample backbone network. Results show a reduction in cost (in terms of the number of deployed LCs) by nearly 6%.