Optical transmission systems, devices, and methods

• US 7,769,290 B2
• Filed: 06/25/2002
• Issued: 08/03/2010
• Est. Priority Date: 06/25/2001
• Status: Active Grant

• Current Assignee: Level 3 Communications LLC (Lumen Technologies, Inc.)
• Original Assignee: Broadwing Corporation (Lumen Technologies, Inc.)
• Inventors: Smith, David F.
• Primary Examiner(s): Phan, Hanh
• Application Number:
  US10/179,719
• Publication Number:
  US 20020196490A1
• Time in Patent Office: 2,961 Days
• Field of Search: 398/59, 398/58, 398/66, 398/67, 398/68, 398/70, 398/71, 398/72, 398/79, 398/3, 398/5, 398/1, 398/60, 398/69, 398/73, 398/83, 398/98, 398/99, 398/100, 370/389, 370/392, 370/352, 370/465, 370/432, 370/468, 725/121, 725/125, 725/127, 725/129, 725/105, 725/106
• US Class Current: 398/5
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0204 Broadcast and select arrangements, e.g. with an optical splitter at the input before adding or dropping
• CPC Class Codes: H04J 14/0209 Multi-stage arrangements, e.g. by cascading multiplexers or demultiplexers
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements
• CPC Class Codes: H04J 14/0217 Multi-degree architectures, e.g. having a connection degree greater than two
• 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 14/0228 Wavelength allocation for communications one-to-all, e.g. broadcasting wavelengths
• CPC Class Codes: H04J 14/0241 Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
• CPC Class Codes: H04J 14/0257 Wavelength assignment algorithms
• CPC Class Codes: H04J 14/0263 Multiplex section layer wavelength assignment algorithms
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0284 WDM mesh architectures
• CPC Class Codes: H04J 14/0286 WDM hierarchical architectures
• CPC Class Codes: H04J 14/0287 Protection in WDM systems
• CPC Class Codes: H04J 14/029 Dedicated protection at the optical multiplex section (1+1)
• CPC Class Codes: H04J 14/0294 Dedicated protection at the optical channel (1+1)

Abstract

An optical system with a first and second network tiers. The first network tier includes a plurality of major nodes optically interconnected by at least one transmission path. The second network tier includes a plurality of minor nodes disposed along the transmission path and the minor nodes are connected to at least one of the major nodes. The minor node is configured to transmit all traffic to an adjacent major node, and the major nodes are configured to transmit to and receive information from other major nodes and minor nodes on transmission paths connected to the major node.

Claims

1. An optical system comprising:

a first network tier including a plurality of nodes optically interconnected by at least one optical communications path;

a second network tier including a plurality of nodes disposed along the at least one optical communications path interconnecting the nodes in the first network tier, wherein;

the nodes in the second network tier are connected to at least one of the nodes in the first network tier via the at least one optical communications path interconnecting the nodes in the first network tier,

at least some traffic between the nodes in the first network tier travels through the at least one optical communications path and through at least one of the nodes in the second network tier without undergoing an optical-electrical-optical conversion,

the nodes in the second network tier are configured to transmit all traffic to an adjacent node in the first network tier via the at least one optical communications path interconnecting the nodes in the first network tier, wherein the adjacent node in the first network tier is part of a working path for the traffic from the nodes in the second network tier, and

the nodes in the first network tier are configured to transmit traffic to and receive traffic from other nodes in the first network tier and the nodes in the second network tier on the at least one optical communications path interconnecting the nodes in the first network tier.

2. The optical system of claim 1, further comprising a third network tier of nodes optically interconnected by at least one optical communications path, wherein the first and third network tiers have different hierarchical attributes, and wherein:

the nodes in the second network tier are connected to at least one of the nodes in the first and third network tiers via the at least one optical communications paths interconnecting the nodes in the first and third network tiers,

at least some traffic between the nodes in the first and third network tiers travels through the at least one optical communications path and through at least one of the nodes in the second network tier without undergoing an optical-electrical-optical conversion,

the nodes in the second network tier are configured to transmit all traffic to an adjacent node in the first and third network tiers via the at least one optical communications path interconnecting the nodes in the first and third network tiers, wherein the adjacent node in the first and third network tiers is part of a working path for the traffic from the nodes in the second network tier, and

the nodes in the first and third network tiers are configured to transmit traffic to and receive traffic from other nodes in the first and third network tiers and the nodes in the second network tier on the at least one optical communications path interconnecting the nodes in the first and third network tiers.

3. The optical system of claim 2, wherein the first and third network tiers have different capacities.

4. The optical system of claim 2, wherein the first and third network tiers have different line rates.

5. The optical system of claim 1, further comprising a fourth network tier of nodes disposed along the optical communications paths, wherein the second network tier and fourth network tier have different hierarchical attributes, and wherein:

the nodes in the second and fourth network tiers are connected to at least one of the nodes in the first network tier via the at least one optical communications path interconnecting the nodes in the first network tier,

at least some traffic between the nodes in the first network tier travels through the at least one optical communications path and through at least one of the nodes in the second and fourth network tiers without undergoing an optical-electrical-optical conversion,

the nodes in the second and fourth network tiers are configured to transmit all traffic to an adjacent node in the first network tier via the at least one optical communications path interconnecting the nodes in the first network tier, wherein the adjacent node in the first network tier is part of a working path for the traffic from the nodes in the second and fourth network tiers, and

the nodes in the first network tier are configured to transmit traffic to and receive traffic from other nodes in the first network tier and the nodes in the second and fourth network tiers on the at least one optical communications path interconnecting the nodes in the first network tier.

6. The optical system of claim 5, further comprising wavelengths transmitted along the optical communications paths between the nodes of the first network tier and the nodes of the second and fourth network tiers, wherein the second network tier reuses wavelengths and the fourth network tier does not reuse wavelengths.

7. The system of claim 1, wherein the at least one optical communications path is an optical fiber.

8. An optical system comprising:

a plurality of nodes in a first network tier optically interconnected by at least one optical communications path;

at least one node in a second network tier disposed along the at least one optical communications path and connected to at least one of the nodes in the first network tier, wherein;

the at least one node in the second network tier is configured to transmit all traffic to an adjacent node in the first network tier through the at least one optical communications path, wherein the adjacent node in the first network tier is part of a working path for the traffic from the nodes in the second network tier,

at least some traffic between the nodes in the first network tier travels through the at least one optical communications path and through the at least one node in the second network tier without undergoing an optical-electrical-optical conversion, and

the nodes in the first network tier are configured to transmit traffic to and receive traffic from other nodes in the first network tier and the at least one node in the second network tier on the at least one optical communications path interconnecting the nodes in the first network tier.

9. The optical system of claim 8, wherein the nodes in the first network tier aggregate traffic from the at least one node in the second network tier.

10. The optical system of claim 8, wherein the adjacent node in the first network tier extracts traffic destined for the at least one node in the second network tier and forwards the traffic to the at least one node in the second network tier.

11. The optical system of claim 8, further comprising wavelengths transmitted along optical communications paths between the nodes in the first network tier, wherein traffic is transmitted between a first node and a second node in the first network tier along a wavelength.

12. The optical system of claim 11, wherein traffic is transmitted between a first node in the first network tier and a second node in the first network tier along more than one wavelength.

13. The optical system of claim 12, wherein the wavelengths transmitted between the first and second nodes in the first network tier use different optical communications paths between the first and second nodes in the first network tier.

14. The optical system of claim 12, wherein the wavelengths transmitted between the first and second nodes in the first network tier use the same optical communications path between the first and second nodes in the first network tier.

15. The optical system of claim 14, wherein the wavelengths are grouped into a spectral group.

16. The optical system of claim 11, wherein traffic is transmitted along a wavelength between a first set of two nodes in the first network tier along a first path and along the same wavelength between a second set of two nodes in the first network tier along a second path where the first and second paths cover diverse paths through the-optical communications path.

17. The optical system of claim 8, wherein the node in the second network tier has a first and a second adjacent node in the first network tier and the first adjacent node in the first network tier provides a working path for the at least one node in the second network tier and the second adjacent node in the first network tier provides a protection path for the at least one node in the second network tier.

18. The system of claim 8, wherein the at least one optical communications path is an optical fiber.

19. A method for optically communicating in an optical network having first and second network tiers, wherein each of the first and second network tiers includes a plurality of nodes, interconnected by at least one optical communications path, comprising:

receiving at a node in the first network tier all traffic from a node in the second network tier, wherein the traffic received at the node in the first network tier from the node in the second network tier traveled through the at least one optical communications path interconnecting the nodes in the first network tier, and wherein the node in the first network tier is part of a working path for the traffic from the nodes in the second network tier;

aggregating traffic received at the node in the first network tier from the node in the second network tier;

transmitting traffic from the node in the first network tier to another node in the first network tier, wherein at least some traffic transmitted between the nodes in the first network tier travels through the at least one optical communications path and through at least one node in the second network tier without undergoing an electrical-optical-electrical conversion.

20. The method of claim 19, wherein the node in the first network tier and the node in the second network tier are adjacent to each other.

21. The method of claim 19, wherein aggregating includes aggregating traffic into a plurality of signal channels based on traffic destination.

22. The method of claim 19, wherein receiving includes receiving at the node in the first network tier traffic from a plurality of nodes in the second network tier.

23. The method of claim 22, wherein aggregating includes aggregating traffic received at the node in the first network tier from a plurality of nodes in the second network tier.

24. The method of claim 19, wherein transmitting further includes transmitting at least one signal channel to another node in the first network tier.

25. The method of claim 19, wherein transmitting further includes transmitting at least one signal channel to a different node in the second network tier.

26. The method of claim 19, further comprising:

receiving traffic at a node in the first network tier, wherein less than all of the traffic is destined for a node in the second network tier;

separating at the node in the first network tier the traffic destined for the node in the second network tier;

transmitting to the node in the second network tier the traffic destined for the node in the second network tier.

27. The method of claim 26, wherein receiving includes receiving traffic from a node in the first network tier.

28. The method of claim 26, wherein receiving includes receiving traffic from a node in the second network tier.

29. The method of claim 26 wherein:

separating includes separating traffic destined for a plurality of nodes in the second network tier;

transmitting includes transmitting traffic to the plurality of nodes in the second network tier.

30. The method of claim 19, further comprising:

providing a working path between a node in the second network tier and a first adjacent node in the first network tier; and

providing a protection path between a node in the second network tier and a second adjacent node in the first network tier.

31. The method of claim 19, wherein the at least one optical communications path is an optical fiber.