METHOD FOR PROVIDING PROTECTION IN AN OPTICAL COMMUNICATION NETWORK AGAINST CONNECTION FAILURES

• US 20110274425A1
• Filed: 02/16/2011
• Published: 11/10/2011
• Est. Priority Date: 05/07/2010
• Status: Active Grant

• Current Assignee: Adtran Networks SE (ADTRAN Holdings, Inc.)
• Original Assignee: ADVA Optical Networking SE (ADTRAN Holdings, Inc.)
• Inventors: Grobe, Klaus
• Granted Patent: US 9,660,758 B2
• Time in Patent Office: Days
• US Class Current: 398/3
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0291 Shared protection at the optical multiplex section (1:1, n:m)

Abstract

The invention relates to an optical communication network (1) comprising a plurality of nodes (2) connected to each other by means of optical fibres (3) in a ring structure, wherein optical signals are transported at working wavelengths (λ_w) in a first direction in said ring structure and wherein optical signals are transported at protection wavelengths (λ_p) in a second direction that is opposite to the first direction in said ring structure, wherein for each node (2) at least one wavelength assignment table (WAT) is provided, wherein to each working wavelength (λ_w) a corresponding protection wavelength (λ_p) is assigned,

wherein in case of a detected connection failure in said ring structure each node (2) which looses at least one connection performs for all working wavelengths (λ_w) affected by said connection failure a lookup in its wavelength assignment table (WAT) to determine the respective protection wavelength (λ_p) and tunes lasers of transceiver units to the determined protection wavelengths (λ_p).

Claims

1. An optical communication network comprising a plurality of nodes connected to each other by means of optical fibres in a ring structure,

wherein optical signals are transported at working wavelengths in a first direction in said ring structure and wherein optical signals are transported at protection wavelengths in a second direction that is opposite to the first direction in said ring structure,

characterized in that

for each node at least one wavelength assignment table is provided, wherein to each working wavelength a corresponding protection wavelength is assigned,

wherein in case of a detected connection failure in said ring structure each node which looses at least one connection performs for all working wavelengths affected by said connection failure a lookup in its wavelength assignment table to determine the respective protection wavelength and tunes lasers of transceiver units to the determined protection wavelengths.

2. The optical communication network according to claim 1, wherein for each node

a first wavelength assignment table is provided for connection failures caused by fibre breaks and

a second wavelength assignment table is provided for connection failures caused by client port transceivers.

3. The optical communication network according to claim 1 or 2,

wherein each node comprises a memory which stores the at least one wavelength assignment table,

wherein each node receives the at least one wavelength assignment table from a master node of said optical communication network via a data communication network by means of an embedded communication channel or by means of an optical supervisory channel.

4. The optical communication network according to claim 2,

wherein each node comprises a control unit for controlling at least one colorless reconfigurable optical add/drop multiplexer connecting said node to said ring structure.

5. The optical communication network according to claim 4,

wherein said colorless reconfigurable optical add/drop multiplexer is a directionless colorless reconfigurable optical add/drop multiplexer.

6. The optical communication network according to claim 5,

wherein said at least one wavelength assignment table is derived automatically from a traffic matrix indicating logical data connections of client ports in said optical communication network.

7. The optical communication network according to claim 6,

wherein said traffic matrix is generated by a master node of said optical communication network in a service discovery.

8. The optical communication network according to claim 7,

wherein said transceiver unit is provided at a client port,

said client port transceiver unit comprising:

a working tunable transceiver having a tunable working laser generating an optical signal at a working wavelength transported in said ring structure in the first direction and

a protection tunable transceiver having a tunable protection laser generating an optical signal at a protection wavelength transported in said ring structure in the second direction.

9. The optical communication network according to claim 7,

wherein the transceiver unit is provided at a client port,

said client port transceiver unit comprising a single tunable transceiver having a tunable laser generating an optical signal at a working wavelength or at a corresponding protection wavelength,

both optical signals being transported in opposite direction within said ring structure of said optical communication network.

10. The optical communication network according to claim 8 or 9,

wherein said client port comprises

a port of a network switch,

a port of a network router or

a port of a network terminal.

11. The optical communication network according to claim 10,

wherein in a normal operation mode of said optical communication network for each protection wavelength at least one colorless reconfigurable optical add/drop multiplexer is adapted to block the optical signal for the respective protection wavelength to avoid a closed loop.

12. The optical communication network according to claim 11,

wherein after detection of a connection failure in a protection operation mode for all determined protection wavelengths blocking of optical signals at the respective protection wavelength is terminated.

13. The optical communication network according to claim 12,

wherein said optical communication network comprises an optical channel shared protection ring.

14. The optical communication network according to claim 13,

wherein said nodes are connected by spans each comprising at least two optical fibres.

15. A method for providing protection in an optical communication network against connection failures of connections between nodes connected to each other by means of optical fibres in a ring structure,

wherein optical signals are transported at working wavelengths in a first direction in said ring structure and

wherein optical signals are transported at protection wavelengths in a second direction that is opposite to the first direction in said ring structure,

wherein for each node at least one wavelength table is provided in which to each working wavelength a corresponding protection wavelength is assigned,

wherein in case of a detected connection failure in said ring structure each node which looses at least one connection performs for all working wavelengths affected by said connection failure a lookup in its wavelength assignment table to determine the respective protection wavelength and tunes lasers of transceiver units to the determined protection wavelengths.