An optical transmission system comprises at least one first connection point and one second connection point arranged to transmit and receive at least one channel signal transmitted via at least one optical means connecting the first connection point and the second connection, wherein each of the at least one channel signal is reversibly configurable to be transmitted in either a first direction or a second direction between the first connection point and the second connection point. A method of transmitting at least one channel signal between a first connection point and a second connection point via at least one optical media in an optical transmission system, wherein each of the at least one channel signal is reversibly configurable to be transmitted in either a first direction or a second direction between the first and the second connection points.