Patent ID: 7742502

Claim:
A method of transporting client layer signals over an Optical Transport Network, said Optical Transport Network being designed for the transport of optical transport signals structured in accordance with the Optical Transport Hierarchy, the Optical Transport Hierarchy providing at least three multiplex layers k with k=1, 2, and 3 and defining corresponding Optical Channel Data Units-k, wherein said Optical Channel Data Units-k with k=1, 2, and 3 are of a size that four transport signals built from Optical Channel Data Units of a lower layer can be multiplexed into one transport signal built from Optical Channel Data Units of the next higher layer, wherein each Optical Channel Data Unit-k comprises an overhead area and a payload area; wherein said Optical Transport Network supports at least said multiplex layer k=1 and corresponding Optical Channel Data Units- 1 , the Optical Transport Hierarchy further defining Optical Channel Payload Units-k, and said Optical Transport Network including switching elements capable of switching Optical Channel Data Units-k between ports of the switching element in accordance with the Optical Transport Hierarchy; and wherein said method comprises the steps of generating an optical transport signal built from first and second Optical Channel Data Units- 0 and a selected higher level Optical Channel Data Unit, the Optical Channel Data Units- 0 being such that two transport signals built from Optical Channel Data Units- 0 can be multiplexed into one transport signal built from Optical Channel Data Units- 1 , the structure of each Optical Channel Data Unit- 0 including a payload area; mapping first and second of said client layer signals, including any overhead of the client layer signals, into the payload areas of said first and second Optical Channel Data Units- 0 , respectively; providing additionally in each of the Optical Channel Data Units- 0 an Optical Channel Payload Unit- 0 -specific overhead area structured to perform functions of an Optical Channel Payload Unit overhead of the Optical Transport Hierarchy; providing additionally in each of the Optical Channel Data Units- 0 an Optical Channel Data Unit- 0 -specific overhead area structured to perform functions of an Optical Channel Data Unit overhead of the Optical Transport Hierarchy; multiplexing the first and second Optical Channel Data Units- 0 into a payload area of the selected higher level Optical Channel Data Unit; and making an entry in an overhead area of the selected higher level Optical Channel Data Unit that enables a switching element in the Optical Transport Network which switches in accordance with the Optical Transport Hierarchy to treat the first and second Optical Channel Data Units- 0 as distinct Optical Transport Hierarchy units and to switch them individually according to the Optical Transport Hierarchy.