A method for transmitting data information, comprising: • selecting, by a first node, at least two optical carriers, wherein the at least two optical carriers correspond to at least two optical frequency slots so that a vacant optical frequency slot exists between two optical frequency slots of the at least two frequency slots (step 41); • modulating, by the first node, data information onto the at least two optical carriers to form a channel of optical signals, so that the channel of optical signals occupies the at least two optical frequency slots, wherein at least one of the at least two optical carriers is transmitted via a different optical path than the other carriers of the at least two optical carriers (step 42); • providing, by a second node, a channel of other optical signals formed by optical signal carriers and modulating other data information onto the optical signal carriers and the channel is borne over at least one optical frequency slot;determining, by a further node, if at least one optical frequency slot used by the other optical signals of the second node can be inserted between the two optical frequency slots used by the optical signals of the first node; • combining, by the further node, the channel of other optical signals with the channel consisting of the at least two optical carriers for generating a combined signal, so that the at least one optical frequency slot determined in the determination step is inserted between the two optical frequency slots used by the optical signals of the first node and providing remaining optical frequency slots used by the other optical signals of the second node in sequence to the optical frequency slots used by the optical signals of the first node; and sending the combined signal. • selecting, by a first node, at least two optical carriers, wherein the at least two optical carriers correspond to at least two optical frequency slots so that a vacant optical frequency slot exists between two optical frequency slots of the at least two frequency slots (step 41); • modulating, by the first node, data information onto the at least two optical carriers to form a channel of optical signals, so that the channel of optical signals occupies the at least two optical frequency slots, wherein at least one of the at least two optical carriers is transmitted via a different optical path than the other carriers of the at least two optical carriers (step 42); • providing, by a second node, a channel of other optical signals formed by optical signal carriers and modulating other data information onto the optical signal carriers and the channel is borne over at least one optical frequency slot;determining, by a further node, if at least one optical frequency slot used by the other optical signals of the second node can be inserted between the two optical frequency slots used by the optical signals of the first node; • combining, by the further node, the channel of other optical signals with the channel consisting of the at least two optical carriers for generating a combined signal, so that the at least one optical frequency slot determined in the determination step is inserted between the two optical frequency slots used by the optical signals of the first node and providing remaining optical frequency slots used by the other optical signals of the second node in sequence to the optical frequency slots used by the optical signals of the first node; and sending the combined signal.