The is directed to extending wavelength routing on a metro network
subtended off an optical agile network. Flexibility on the subtended
metro network is obtained by either tuning the head-end transmitter on a
metro wavelength that is the operating wavelength of the route to a
specified tail-end node (tunable source, fixed wavelength-route
dependency) or/and tuning a specified route to the metro wavelength
(fixed source, tunable wavelength-route dependency). The routes may be
tuned at one or both ends.