An optical network includes a plurality of subnets. The subnets each
include a plurality of add/drop nodes coupled to the optical ring and
operable to passively add and drop traffic to and from the optical ring.
The network further includes a plurality of gateway nodes. The gateway
nodes are each coupled to the optical ring at a boundary between
neighboring subnets and operable to selectively pass and terminate
wavelengths between subnets to allow wavelength reuse in the subnets and
to provide protection switching.