Apparatus and method for internet protocol flow ring protection switching

• US 6,721,269 B2
• Filed: 05/25/1999
• Issued: 04/13/2004
• Est. Priority Date: 05/25/1999
• Status: Expired due to Fees

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Buchanan, William M., Lefoley, Stephen George, Cao, Yang
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): NGUYEN, HANH N
• Application Number:
  US09/318,694
• Publication Number:
  US 20020181485A1
• Time in Patent Office: 1,785 Days
• Field of Search: 370/225, 370/216, 370/217, 370/227, 370/228, 370/218, 370/221, 370/400, 370/238, 370/242, 370/248, 370/238.1, 370/249, 370/406, 359/115, 359/117, 359/123, 359/124, 359/128, 709/241, 709/242, 709/238, 709/239
• US Class Current: 370/227
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04L 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• 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 11/04 for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: H04Q 2213/13141 Hunting for free outlet, circuit or channel
• CPC Class Codes: H04Q 2213/13163 Fault alarm
• CPC Class Codes: H04Q 2213/13166 Fault prevention
• CPC Class Codes: H04Q 2213/13167 Redundant apparatus
• CPC Class Codes: H04Q 2213/13204 Protocols
• CPC Class Codes: H04Q 2213/13216 Code signals, frame structure
• CPC Class Codes: H04Q 2213/1329 Asynchronous transfer mode, ATM
• CPC Class Codes: H04Q 2213/13296 Packet switching, X.25, frame relay
• CPC Class Codes: H04Q 2213/13353 Routing table, map memory
• CPC Class Codes: H04Q 2213/13367 Hierarchical multiplexing, add-drop multiplexing
• CPC Class Codes: H04Q 2213/13389 LAN, internet

Abstract

A router in accordance with the principles of the present invention employs explicit routing protocols to establish a plurality of explicitly routed label switched paths between source and sink routers. The sink router selects one of these explicitly routed paths as a primary path and communicates along that path. Upon a failure in a path selected as a primary path, a secondary path is instantaneously selected as the new primary path. Since the new route has already been established, there is no need to re-compute the path at the time of a failure. Consequently, a new path is rapidly established in response to the failure of a path. One of the new routers may employ physical level maintenance information, such as loss of signal (LOS) or loss of pointer (LOP), for example, to detect such path failures. Additionally, the new router may employ provisioned flow information to propagate path failure alarms.

Claims

1. A muter comprising:

a first port through which datagrams for a given flow may be received from a primary path that originates at an ingress router;

a second port through which datagrams for the flow may be received from at least one secondary path contemporaneously with the reception at said first port, said at least one secondary path at least partially distinct from the primary path but originating at the same ingress router; and

a controller for preferentially selecting datagrams received via said first port, said controller comprising a memory for program instructions, and a processor for executing said instructions to configure the router perform the steps of;

establishing the primary path for the given flow be en the ingress router and an egress router;

establishing said at least one secondary path for a given flow between the ingress muter and the egress router;

in response to a failure in the primary path, automatically selecting an operational one of said at least one secondary path for primary communication between the ingress muter and the egress router; and

in response to the selection of said secondary path, automatically establishing at least one replacement secondary, at least partially distinct, path.

2. The router of claim 1 wherein the controller designates the port from which it selects datagrams for routing as the routers primary port for the given flow and the second port as its secondary port.

3. The router of claim 2 wherein the controller is responsive to physical level maintenance information that indicates a failure in the path associated with the primary port by selecting datagrams from the secondary port or routing.

4. The router of claim 3 wherein the controller is further responsive to physical level maintenance information by employing provisioned flow to propagate alarms.

5. The router of claim 4 wherein the controller is further responsive to physical level maintenance information that indicates a failure in the primary path by designating the secondary path as the primary path and by a playing the propagation of alarms to establish one or more new secondary paths.

6. The router of claim 5 wherein the physical level maintenance information is SONET physical level maintenance information.

7. The router of claim 6 wherein the controller is responsive to SONET loss of signal physical level maintenance information by selecting datagrams from the secondary port for routing.

8. The router of claim 5 wherein the physical level maintenance information is SDH physical level maintenance information.

9. The router of claim 1 wherein the controller is configured to monitor physical level maintenance information.

10. An Internet protocol communications a stem comprising:

an ingress router;

an egress router, and

a plurality of explicitly routed label switched paths contemporaneously carrying like datagrams, and established for single flow between the ingress router and the egress router, wherein the ingress router, the egress router, and any intermediate routers comprise;

a first port through which datagrams for a given flow may be received from a primary path that originates at the ingress router;

a second port through which datagrams for the flow may be received from at least one secondary path contemporaneously with the reception at said first port, said at least one secondary path at least partially distinct from the primary path but originating at the same ingress router; and

a controller for preferentially selecting datagrams received via said first port, said controller comprising a memory for program instructions, and a processor for executing said instructions to configure the router to perform the steps of;

establishing the primary path for the given flow between the ingress router and the egress router;

establishing said at least one seconds path for a given flow between the ingress muter and the egress router;

in response to a failure in the primary path, automatically selecting an operational one of said at least one secondary paths for primary communication between the ingress router and the egress router; and

in response to the selection of said as secondary path, automatically establishing at least one replacement secondary, at least partially distinct, path.

11. The system of claim 10 wherein the controller designates the port from which it selects datagrams for routing as the router'"'"'s primary port for the given flow and the second port as its secondary port.

12. The system of claim 11 wherein the controller is figured to monitor physical level maintenance information.

13. The system of claim 11 wherein the controller is responsive to physical level maintenance information that indicates a failure in the a path associated with the primary port by selecting datagrams from the secondary port for routing.

14. The system of claim 13 wherein the controller is fu her responsive to physical level maintenance information by employing provisioned flow to propagating alarms.

15. The system of claim 14 wherein the controller is further responsive to physical level maintenance information that indicates a failure in the primary path by designating the secondary path as the primary path and by employing the propagation of alarms to establish one or more new secondary paths.

16. The system of claim 15 wherein the physical level maintenance information is SONET physical level maintenance information.

17. The system of claim 16 wherein the controller is responsive to SONET loss of signal physical level maintenance information by selecting datagrams from the secondary port for routing.

18. The system of claim 15 wherein the physical level maintenance information is SDH physical level maintenance information.

19. A method of communicating datagrams through an Internet protocol network comprising the steps of:

for each router, establishing a primary explicitly routed label switched path for a given data flow between an ingress router and an egress router;

for each router, establishing at least one secondary, at least partially distinct, explicitly routed label switched path for a given data flow between the ingress router and the egress router, such that the data flow from said at least one secondary, at least partially distinct, explicitly routed label switched path is received by a second port of the egress router contemporaneously with the reception of the data flow from said primary explicitly routed label switched path at a first port of the egress router;

in response to a failure in the primary explicitly rout label switched path of any one or more of said routers, automatically selecting an operational one of said at least one secondary explicitly routed label switched paths, for each of the tailed routers, for primary communication between the ingress router and the egress router; and

in response to the selection of said secondary explicitly routed label switched paths, automatically establishing at least one replacement secondary, at least partially distinct, explicitly routed label switched path.

20. The method of claim 19 further comprising the step of monitoring physical level maintenance information related to the path from which datagrams are selected for routing.

21. The method of claim 20 further comprising the step of selecting datagrams for routing at the egress muter from another of the explicitly routed label switched paths should physical level maintenance information related to the path from which datagrams were originally selected indicate a failure in that path.

22. The method of claim 21 further comprising the step of employing provisioned flow to propagate alarms in response to such a failure.

23. The method of claim 19, further comprising the step of:

in response to failure to automatically establish at least on replacement secondary, at least partially distinct, routed label switched path, generating an alarm indicative of said failure.