Wavelength Selection

• US 20080056717A1
• Filed: 07/12/2005
• Published: 03/06/2008
• Est. Priority Date: 07/19/2004
• Status: Active Grant

• Current Assignee: British Telecommunications (BT Group Plc) (BT Group PLC), British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: King, John, Niven-Jenkins, Benjamin
• Granted Patent: US 8,538,260 B2
• Time in Patent Office: Days
• US Class Current: 398/57
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• CPC Class Codes: H04J 14/0241 Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
• CPC Class Codes: H04J 14/0284 WDM mesh architectures

Abstract

A method of selecting a wavelength for use in transmitting optical data along a path in an optical network is disclosed. Previously known methods for selecting wavelengths do not consider how a wavelength selection decision will affect future connection attempts along paths that have one or more links in common with the path for which the wavelength is being selection. Consequently, a future connection attempt may be blocked because there are no wavelengths available end-to-end along the entire path that is to be set up. In the proposed method, the wavelengths that are available for use end-to-end along the path are found, the wavelengths that are available on each link attached to each node on the path are found and a wavelength that is available end-to-end and that is more available on the links attached to the nodes

Claims

1. A method of selecting a wavelength for use in transmitting optical data along a path in an optical network, said optical network comprising a plurality of nodes interconnected by optical fibre links, said method comprising:

finding the wavelengths available for use end-to-end along said path;

finding the wavelengths available on each link attached to each node on said path;

selecting a wavelength that is available end-to-end and that is more available on the links attached to the nodes on said path than other wavelengths.

2. A method according to claim 1, further comprising the antecedent step of selecting said path using a shortest path first algorithm.

3. A method according to claim 2, wherein the metric used in said algorithm is related to the wavelength usage on the links.

4. A method according to claim 2, wherein the selecting of said path comprises extending said path one link at a time.

5. A method according to claim 4, further comprising performing an end-to-end viability check on the path including a proposed link before extending the path with said proposed link.

6. A method according to claim 5, wherein said viability check is based on the optical characteristics of said path.

7. A method according to claim 6, wherein said viability check determines if the end-to-end optical loss of the path including a proposed link is acceptable.

8. A digital data carrier carrying a program of instructions executable by processing apparatus to perform the method steps as set out in claim 1.

9. A node for use in an optical network, said optical network comprising a plurality of nodes interconnected by optical fibre links, said node comprising:

finding means for;

finding the wavelengths available for use in transmitting optical data end-to- end along a path in said optical network;

finding the wavelengths available on each optical fibre link attached to each node on said path;

selecting means for selecting a wavelength that is available end-to-end and that is more available on the links attached to the nodes on said path than other wavelengths.

11. A node according to claim 9, wherein said node comprises a node on said path.

12. A node according to claim 11, wherein said node comprises the ingress node of said path.

13. An optical network comprising a plurality of nodes interconnected by optical fibre links, wherein one or more of said nodes comprises a node according to claim 9.

10. A node for use in an optical network, said optical network comprising a plurality of nodes interconnected by optical fibre links, said node comprising:

a storage medium having recorded therein processor readable code processable to select a wavelength for use in transmitting optical data along a path in said optical network, said code comprising;

wavelength finding code processable to;

find the wavelengths available for use end-to-end along said path;

find the wavelengths available on each link attached to each node on said path;