Back-up restoration technique for SONET/SHD rings

• US 6,370,110 B1
• Filed: 09/16/1998
• Issued: 04/09/2002
• Est. Priority Date: 09/16/1998
• Status: Expired due to Fees

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Eslambolchi, Hossein
• Primary Examiner(s): Rao, Seema S.
• Assistant Examiner(s): Sam, Phirin
• Application Number:
  US09/154,326
• Time in Patent Office: 1,301 Days
• Field of Search: 370/216, 370/220, 370/222, 370/223, 370/224, 370/228, 370/248, 370/244, 370/245, 370/351, 370/352, 370/358, 370/367, 370/389, 370/395, 370/426, 370/463, 370/466, 370/487, 370/535, 370/217, 370/219, 370/221, 370/227, 370/241, 370/242, 370/406, 359/110, 359/119, 709/227, 709/239, 714/25, 714/43
• US Class Current: 370/216
• 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 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A restoration network architecture (100) includes both service and protection SONET/SDH rings (15, 17) as well as a mesh network (25) including point-to-point paths (26₁-26₂). Monitoring Equipment (28, 30) monitor the status of service links (14₁-16₄) and protection links (16₁-16₄) in the service and protection rings, respectively, along with the status of the point-to point links in the mesh network. Upon detecting a failure of one of the service links and point-to-point links, an Operations Systems Data Server (32) establishes a restoration path based on the available protection links and available point-to-point links. Traffic is then restored on such the restoration path. In this way, a failure in the service ring can be restored in the mesh network while a failure in the mesh network can be restored in the protection ring.

Claims

1. For use with a network that includes (i) at least one service ring configured of first links that each run between a pair of nodes to form a ring-like path;

(ii) at least one protection ring configured of second links that each runs between said pair of nodes in parallel with a corresponding first link; and

(iii) a mesh sub-network network that includes a plurality of third links that collectively provide point-to-point connectivity between selected nodes, a method for restoring traffic in the event of a failure of a failed link, comprising;

monitoring the service and protection rings, respectively, to determine whether each of the first and second links is one of a failed or active state;

simultaneously monitoring the mesh network to determine whether each third link is in an active or failed state; and

establishing, in response to a determination that one of said first and third links has failed, a restoration path comprised of at least one of said second and third links that are in an active state, and

effecting the switching of traffic from a failed one of said first links and third links, as determined from said monitoring steps, onto said restoration path.

2. The method according to claim 1 wherein a restoration path is established from one or more active third links in response to a failure of a first link.

3. The method according to claim 1 wherein a restoration path is established from one or more active second links in response to a failure of a third link.

4. A restoration network comprising:

at least one service ring configured of first links that each runs between a pair of nodes to form a ring-like path,

at least one protection ring configured of second links that each runs between said pair of nodes in parallel with a corresponding first link;

a mesh sub-network network that includes a plurality of third links that collectively provide point-to-point connectivity between selected nodes;

means for monitoring the service and protection rings to determine whether each of the first and second link is one of a failed or active state; and

for monitoring the mesh network simultaneously with the service and protection rings to determine whether each third link is in an active or failed state; and

means for establishing, in response to a determination that one of said first and third links has failed, a restoration path comprised of at least one of said second and third links that is in an active state, and

means for switching traffic from a failed one of said first links and third links, as determined from said monitoring steps, onto said restoration path.

5. The network according to claim 4 wherein said restoration path establishing means comprises:

a common language specific equipment Assignment (CLSEA) system that maintains information concerning link assignments; and

an operations systems data server (OSDS) for establishing the restoration path in accordance with information from said CLSEA system and said monitoring means.

6. The apparatus according to claim 4 wherein each of said first, second, and third links each comprise an optical fiber link.

7. The apparatus according to claim 4 wherein the monitoring means comprises:

a transport maintenance administration system (TMAS) for monitoring traffic in said network; and

an element monitoring system for monitoring elements in said service and protection rings.