The increasing popularity of all-optical networks has led to extensive research on the routing and wavelength assignment problem, also termed as the
Routing and Path Coloring problem
(RPC). Here we present a polynomial time algorithm that solves RPC exactly in
generalized tree networks
of bounded degree. This new topology is of practical interest since it models tree-like backbone networks connecting bounded-size LANs of any form. Tree-like backbone structure is very common in practice and bounded size LANs is a reasonable assumption, since LANs are by nature networks unable to sustain a large number of hosts.