Wavelength regeneration in a network

• US 9,014,022 B2
• Filed: 09/06/2011
• Issued: 04/21/2015
• Est. Priority Date: 11/15/2010
• Status: Active Grant

• Current Assignee: Level 3 Communications LLC (Lumen Technologies, Inc.)
• Original Assignee: Level 3 Communications LLC (Lumen Technologies, Inc.)
• Inventors: Peterson, Benjamin K., Clark, Laurel
• Primary Examiner(s): Shah, Chirag
• Assistant Examiner(s): SMITH, JOSHUA Y
• Application Number:
  US13/225,712
• Publication Number:
  US 20120123815A1
• Time in Patent Office: 1,323 Days
• Field of Search: None
• US Class Current: 370/252
• CPC Class Codes: G06Q 10/063 Operations research, analysis or management
• CPC Class Codes: H04J 14/021 Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
• CPC Class Codes: H04J 14/0254 Optical medium access
• CPC Class Codes: H04J 14/0257 Wavelength assignment algorithms
• CPC Class Codes: H04J 14/0263 Multiplex section layer wavelength assignment algorithms
• CPC Class Codes: H04L 41/22 comprising specially adapted graphical user interfaces [GUI]

Abstract

An optical network including a plurality of gateway nodes interconnected with a plurality of intermediate nodes with segments of fiber. The network includes a plurality of devices, such as reconfigurable optical add drop multiplexors, optimally placed at various nodes throughout the network. The device placement is optimized with an integer linear programming analysis considering span definition such that any given span involves some number of segments not exceeding a number of segments that would require wavelength regeneration, cost of placement of a device at a given node, cost of wavelength regeneration, and various parameters and constraints.

Claims

1. A computer-implemented method for optimizing placement of devices at nodes in a network, the computer-implemented method comprising:

using at least one processor,

identifying a plurality of spans in the network that can be traversed by a wave without intermediate regeneration;

identifying a cost associated with placement of a device at a given node in the network;

identifying a cost associated with wavelength regeneration in the network;

for each given span, identifying;

a maximum number of intermediate nodes for the given span;

a maximum bandwidth for the given span based on a maximum number of wavelengths for the given span and a maximum wavelength bandwidth;

specifying a constraint such that if a given span is to carry traffic, the given span may not;

have more than the identified maximum number of intermediate nodes for the given span; and

carry more than the maximum bandwidth for the given span;

specifying a constraint such that each given span used to carry traffic has a device placed at each node endpoint of the given span;

applying at least one first linear programming model to a forecasted traffic demand, the identified spans, the identified costs associated with placement of a device at each given node, the identified cost associated with wavelength regeneration in the network, and the one or more specified constraints; and

identifying, from the model, one or more nodes in the network at which a device should be placed to;

handle the forecasted traffic demand; and

optimize the number of devices to be added to the network.

2. The computer-implemented method as recited in claim 1, wherein at least one of the devices is a reconfigurable optical add-drop multiplexer (ROADM).

3. The computer-implemented method as recited in claim 2, wherein at least one given node in the network comprises an amplifier site.

4. The computer-implemented method as recited in claim 3, further comprising:

on a graphical user interface associated with the processor, rendering an indication of the one or more nodes in the network at which a device should be placed.

5. The computer-implemented method as recited in claim 2 further comprising:

specifying a constraint such that each node that comprises a gateway also comprises a ROADM;

specifying a constraint such that each span that is overlapping with another span can carry no more than a maximum number of wavelengths on a single span waves, combined;

specifying a constraint such that no span can carry more total circuit bandwidth than the combined bandwidth of all of the spans wavelengths; and

specifying a constraint such that each circuit traverses a connected chain of spans from a start point to the chain to an end point of the chain.

6. The computer implemented method as recited in claim 5 further comprising:

applying at least one second linear programming model to specify indices of specific wavelengths to be used on each span such that any of the overlapping spans do not share a wavelength of an index of the overlapping span.

13. A tangible, non-transitory, computer readable medium comprising computer executable instructions that when executed by a processor perform the method of claim 1.

7. An optical network comprising:

a plurality of fiber segments interconnecting a plurality of gateway nodes and a plurality of intermediate nodes to form a network, each of the plurality of gateway nodes comprising a device configured to add or remove wavelengths from a particular fiber segment, the plurality of intermediate nodes having a device placed thereat when;

8. The optical network as recited in claim 7 wherein:

R_n=1, for each of the plurality of gateway nodes n;

S_s≦

R_As and S_s≦

R_Zs, for all spans s;

9. The network as recited in claim 8 wherein the device is a reconfigurable optical add drop multiplexor (ROADM).

10. The network as recited in claim 9 wherein:

11. The network of claim 10 wherein:

12. The network as recited in claim 7 wherein at least one of the plurality of intermediate nodes comprises an amplifier site.