Ring-mesh networks

• US 6,848,006 B1
• Filed: 05/30/2000
• Issued: 01/25/2005
• Est. Priority Date: 05/30/2000
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Hermann, Karen E.
• Primary Examiner(s): Wiley, David
• Assistant Examiner(s): NGUYEN, PHUOC H
• Application Number:
  US09/579,504
• Time in Patent Office: 1,701 Days
• Field of Search: 709/201, 709/204, 709/206, 709/207, 709/224, 709/231, 709/226, 709/225, 709/229, 709/228, 709/251, 709/239, 398/24, 398/48, 398/83, 398/9
• US Class Current: 709/239
• 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 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0284 WDM mesh architectures
• CPC Class Codes: H04J 14/0291 Shared protection at the optical multiplex section (1:1, n:m)
• CPC Class Codes: H04J 2203/0042 Ring
• CPC Class Codes: H04J 2203/006 Fault tolerance and recovery
• CPC Class Codes: H04J 3/085 for ring networks, e.g. SDH/SONET rings, self-healing rings, meashed SDH/SONET networks
• CPC Class Codes: H04L 12/44 Star or tree networks

Abstract

A ring-mesh network architecture is provided for increasing the working/protection bandwidth ratio (W/PBR) of transport networks. The ring-mesh network has mesh connections between some nodes, the traffic on the mesh connections being unprotected. This increases the W/PBR from the current 1:2 value to (n−2)/(n−1), where n is the number of nodes, (n−1) is the number of connections on each node and (n−2) is the number of working connections on each node for one direction of traffic. Ring-mesh networks with add/drop multiplexers in the mesh connection are also provided.

Claims

1. A ring-mesh network with a bandwidth (BW) on all lines, for transporting a traffic signal between a source and a destination node, comprising:

a bidirectional line switched ring network, having a ring working bandwidth of 50% BW and a ring protection bandwidth of 50% BW;

a mesh connection between a first and a second node of said ring network, having a mesh working bandwidth of 100% BW allocated to a mesh working traffic; and

wherein all lines have the same bandwidth, wherein the path of said traffic signal comprises one of a ring-only component, a hybrid component, and both a ring and a hybrid component, and

wherein said hybrid component comprises a first ring component between said source node and said first node, a mesh component between said first node and said second node, and a second ring component between said second node and said destination node.

2. A ring-mesh network as claimed in claim 1, wherein said ring components are 100% protected.

3. A ring-mesh network as claimed in claim 1, wherein said mesh component is protected by said ring protection bandwidth.

4. A ring-mesh network as claimed in claim 1,

further comprising a second mesh connection between said second node and another node different from said first node, wherein said second node transfers said traffic signal from said mesh connection to said second ring connections only.

5. A method for creating a ring-mesh network with a bandwidth BW on all lines, comprising:

connecting a plurality of traffic nodes in a bidirectional line switched ring network;

allocating to said ring network 50% of the BW for a ring working bandwidth and 50% of the BW to a ring protection bandwidth;

providing a mesh connection between a first and a second node of said ring network;

allocating 100% of the BW to a mesh working bandwidth; and

transporting a traffic signal between a source and a destination node of said ring mesh network, on a route including said mesh connection, said traffic signal using 50% of said mesh working bandwidth,

wherein working/protection BW′

ratio for said traffic signal is higher than 0.5.

6. A method as claimed in claim 5, wherein said traffic signal comprises one of a ring component, a hybrid component, and both a ring and a hybrid component.

7. A method as claimed in claim 6, wherein said ring component travels along said ring network between said source and destination nodes.

8. A method as claimed in claim 6, wherein said hybrid component comprises a first ring component traveling along said ring network between said source node and said first node, a mesh component traveling along said mesh connection, and a second ring component travelling along said ring network between said second node and said destination node.

9. A method as claimed in claim 8, wherein said mesh connection transports a further mesh component, within the remaining 50% of said mesh network bandwidth, for connecting said source node with a further destination node placed on said ring network on the opposite side from said destination node with respect to said second node.

10. A method as claimed in claim 7, wherein said ring component is protected by said ring protection bandwidth.

11. A method as claimed in claim 8, wherein said ring components and said mesh component are protected by said ring protection bandwidth.

12. A method as claimed in claim 5, wherein said traffic signal comprises a first hybrid component for connecting said source node with said destination node and a second hybrid component for connecting said source node with a second destination node, each said hybrid components having 50% of the BW on said mesh connection.

13. A method as claimed in claim 5, wherein said source node is said first node.

14. A method as claimed in claim 5, wherein said ring-mesh network operates in one of the following modes:

an idle mode wherein said traffic signal uses said ring and mesh working bandwidth;

a ring protection switching mode in case of a fault affecting said ring network, wherein said traffic signal is switched from said ring working bandwidth onto said ring protection bandwidth; and

a ring-mesh protection switching mode in case of a fault affecting said mesh connection, wherein said traffic signal is switched from said mesh working bandwidth over said ring protection bandwidth.

15. A method as claimed in claim 14 wherein said ring-mesh protection switching mode comprises, for an interruption on said mesh connection:

informing said first and second node of said interruption;

at said first node, switching said traffic signal from said ring working bandwidth onto said ring protection bandwidth towards said second node;

at said second node, switching said traffic signal from said ring protection bandwidth onto said ring working bandwidth towards said destination node.

16. A method as claimed in claim 15, wherein said traffic signal uses said ring protection bandwidth between said first and said second nodes around either side of said ring network.

17. A method as claimed in claim 15, wherein said traffic signal uses said ring protection bandwidth between said first and said second nodes around a shortest side of said ring network.

18. A method as claimed in claim 15, wherein said destination node obtains said traffic signal directly from said ring protection bandwidth using a head end ring switch protocol.

19. A method as claimed in claim 14, wherein said ring-mesh protection switching mode comprises, for a failure of said first node:

informing said second node and a downstream node of said failure;

at said, second node, switching said traffic signal from said ring working bandwidth to said ring protection bandwidth;

at said downstream node, switching said traffic signal from said ring protection bandwidth onto said ring working bandwidth towards said destination node.

20. A method as claimed in claim 5, further comprising:

connecting a plurality of add/drop multiplexing ADM nodes into said mesh connection;

allocating 50% BW of said mesh working traffic to a mesh pass-through traffic for direct communication between said first and second node; and

allocating 50% BW of said mesh working traffic to a mesh add/drop traffic for communication between said ADM nodes.

21. A method as claimed in claim 20, further comprising:

detecting an interruption in said mesh connection between a first mesh node and a second mesh node, for the direction of traffic from said first node to said second node;

at said first node, switching said pass-through traffic onto said ring protection bandwidth towards said second node;

at said first mesh node, switching said add/drop traffic onto said pass-through bandwidth towards said first node;

at said second mesh node, selecting said add/drop traffic from said pass-through bandwidth;

at said first node, directing said add/drop traffic towards said second node along said ring network.

22. A method as claimed in claim 21, further comprising at said first node, separating said pass-through traffic into a West and an East component, and switching said West and East components onto said ring protection bandwidth towards said second node.

23. A method as claimed in claim 22, wherein said West and said East components have same bandwidth.

24. A method as claimed in claim 20, further comprising:

detecting fault at said first node affecting the direction of traffic from said first node to said second node;

identifying said fault at said second node and at a downstream mesh node;

dropping said pass-through traffic and said add/drop traffic between said first node and said downstream node, at said downstream mesh node, switching said add/drop traffic onto said pass-through bandwidth towards said first node;

at said second mesh node, switching any pass-through traffic directed to a destination node on said ring nodes onto said pass-through bandwidth towards said second node;

at said second node, switching said pass-through traffic onto said ring protection bandwidth towards said destination node.

25. A method as claimed in claim 24, further comprising at said second node separating said pass-through traffic into an East and a West component and switching said West and East components onto said ring protection bandwidth towards said destination node.

26. A method as claimed in claim 25, wherein said West and said East components have same bandwidth.