Link-Rate Assignment in a WDM Optical Mesh Network with Differential Link Capacities: A Network-Engineering Approach

Wavelength-division multiplexing (WDM) optical networks are characterized by maturity, high-capacity, agility, flexibility, and cost-efficiency. Today, optical transmission rates are increasing from 10 Gbit/s to 100 Gbit/s which increases the network's flexibility for capacity provisioning. We study the problem of dimensioning optical WDM networks under traffic growth. Particularly, we study link-rate assignment and capacity expansion (namely network engineering). Our study shows that, with careful link-rate assignment, the network's traffic can be satisfied and any traffic growth can be accommodated using the network's current resources with some additional resources so that cost is minimized. Our study also shows that, by careful selection, only a few links with high rates can meet the capacity needs of the network and that any additional high-rate links (extra cost) may not significantly improve the network's efficiency.