Optical network and method for processing data in an optical network

An optical UDWDM PON network (203) is provided comprising an optical line termination (202) coupled to a backbone network, in particular to an optical long haul network and a local exchange (204) coupled to an optical access network, wherein said local exchange provides an optical connection between an optical network unit (205 - 207) of a tree topology and the optical line termination (202), which is part of a ring topology. Upstream and downstream signals are transmitted via UDWDM channels assigned to each optical network unit (ONU) with corresponding unique wavelengths. Also, a method is suggested for processing data in such an optical network.