A network node for an optical transport network is disclosed, which has a signal input for receiving a multiplexed transport signal carrying a number of n timeslots of a fixed size data capacity, a demultiplexer for demultiplexing the received signal into a number of m>1 sub-signals, each sub-signal carrying a fraction of n/m of said timeslots, one or more space switch modules for configurably switching said sub-signals, and a multiplexer receiving sub-signals from said one or more space switch modules; for multiplexing timeslots from said sub-signals into an outgoing multiplexed transport signal carrying n of said timeslots. The multiplexer is connected to the one or more switch modules over a number of l>m interconnections and receives from said one or more switch modules up to l sub-signals. Moreover, the multiplexer can be configured to select the n timeslots for the outgoing multiplexed transport signal from the up to l sub-signals.