Wavelength Selective WDM Network Design: How Bad is Shortest Path Routing?

Given a collection of lightpath requests, we consider the problem of allocating fibers to the links of a WDM network at minimum cost, such that all lightpath requests can be simultaneously realized. It is known that, under modular fiber capacity assumptions, shortest path routing may not minimize the total fiber cost. In this paper, we extend our previous work for wavelength convertible networks, and theoretically quantify the increase in fiber cost due to shortest path routing in networks without wavelength converters. In particular, we prove that shortest path routing is asymptotically cost-optimal in heavily loaded networks, and asymptotically near-optimal in large, sparse networks that support all-to-all communication.