Multi-rate transparent MUX for optical communications networks

1. A method in a network interface of bit-transparent MUXing a client signal into a fixed-length container for transport through an optical communications network coupled to the network interface, the method comprising steps of:

computing a stuffing ratio (α) based on a line rate of the client signal and a payload capacity of the container;

computing a number (N FS ) of fixed stuffs based on the stuffing ratio (α);

inserting N FS fixed stuffs into a payload of the container;

inserting bytes of the client signal into a residual portion of the payload of the container; and

storing the computed number N FS in a predetermined location of the container,

wherein the computed number of fixed stuffs NFS is represented by a pair of values (FS 1 and FS 2 ), respectively associated with integer and fractional components of the number N FS .

2. A method as claimed in claim 1 , wherein the container is a logical Optical Transport Network (OTN) container.

3. A method as claimed in claim 2 , wherein the container has a line rate based on an optimum cost/bit/km of the optical communications network.

4. A method as claimed in claim 2 , wherein the predetermined location of the container used for storing the computed number N FS comprises one or more unallocated fields of the container overhead.

5. A method as claimed in claim 1 , wherein the step of inserting N FS fixed stuffs into the payload comprises steps of:

inserting the integer number (FS 1 ) of fixed stuffs into the payload; and

inserting an additional fixed stuff into the payload of each Nth container, where N=1/FS 2 .

6. A method as claimed in claim 1 , wherein the step of inserting N FS fixed stuffs into the payload comprises steps of:

inserting the integer number (FS 1 ) of fixed stuffs into the payload;

representing the fractional number (FS 2 ) as a byte value, and, for each bit FS 2 [i], 0<i <7, having a value of binary “1”, inserting an additional fixed stuff into the payload of each Nth container, where N=2 8-i .

7. A method as claimed in claim 1 , wherein the container payload is divided into two or more sectors, and wherein the steps of computing a stuffing ratio (α), computing a number (N FS ) of fixed stuffs, inserting N FS fixed stuffs into a payload of the container, inserting bytes of the client signal into a residual portion of the payload of the container, and storing the computed number N FS are repeated for each sector.

8. A method as claimed in claim 7 , wherein the sectors are of equal size.

9. A method as claimed in claim 7 , wherein a size of at least one sector differs from that of at least one other sector.

10. An interface for bit-transparent MUXing of a plurality of client signals for transport through an optical communications network, the interface comprising:

at least one client facing MUX block for MUXing at least one client signal into an intranode transport container having a predetermined payload capacity; and

a network facing MUX-block for MUXing at least one intranode transport container into a transport network container of the optical communications network;

wherein at least the client facing MUX blocks are configured to:

compute a stuffing ratio (α) based on a line rate of the client signal and a payload capacity of the container;

compute a number (N FS ) of fixed stuffs based on the stuffing ratio (α);

insert N FS fixed stuffs into a payload of the container;

insert bytes of the client signal into a residual portion of the payload of the container; and

store the computed number N FS in a predetermined location of the container,

wherein the computed number of fixed stuffs N FS is represented by a pair of values (FS 1 and FS 2 ), respectively associated with integer and fractional components of the number N FS .

11. The interface as claimed in claim 10 , wherein the intranode transport container is an over-clocked Optical Transport Network (OTN) container.