System and method for discovering neighboring nodes

• US 8,218,968 B2
• Filed: 06/18/2007
• Issued: 07/10/2012
• Est. Priority Date: 10/16/2006
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Bardalai, Snigdho Chandra
• Primary Examiner(s): CURS, NATHAN M
• Application Number:
  US11/764,507
• Publication Number:
  US 20080107415A1
• Time in Patent Office: 1,849 Days
• Field of Search: 398 2- 5, 398/9, 398/25, 398/57, 398/156, 370/248
• US Class Current: 398/57
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

A method for discovering neighboring nodes includes establishing a first optical connection with a first node using a first link. The method also includes detecting a change in the first optical connection. The method further includes initiating a discovery process to detect whether the first node or a second node is using the first link. The method additionally includes, upon detecting a second node using the first link, disabling the first optical connection and establishing a second optical connection with the second node.

Claims

1. A method for discovering neighboring nodes, comprising:

establishing a first optical connection with a first node using a first link, wherein the first optical connection with the first node uses a communication protocol that is defined to detect a type of reconfiguration event in the first optical connection when no communication exists over the first link for longer than a defined recovery interval, the type of reconfiguration event comprising a change in a node that is using the first link;

detecting a reconfiguration event of said type in the first optical connection while a connection exists over the first link before the defined recovery interval elapses;

initiating a discovery process to detect whether the first node or a second node is using the first link; and

upon detecting the second node using the first link, disabling the first optical connection and establishing a second optical connection with the second node, wherein disabling the first optical connection comprises releasing at least one resource associated with the first optical connection to prevent stranding of the resource.

2. The method of claim 1, wherein establishing the second optical connection comprises debouncing the second optical connection.

3. The method of claim 1, wherein the communication protocol comprises Link Management Protocol (LMP) and initiating the discovery process comprises initiating an LMP discovery process.

4. The method of claim 1, further comprising:

initiating a timer set to a recovery interval; and

upon lapse of the recovery interval without detection of the second node, transitioning a finite state machine associated with the first optical connection to a down state.

5. The method of claim 1, wherein detecting a change in the first optical connection comprises transmitting a link verification message.

6. A system for discovering neighboring nodes, comprising:

an interface operable to;

establish a first optical connection with a first node using a first link, wherein the first optical connection with the first node uses a communication protocol that is defined to detect a type of reconfiguration event in the first optical connection when no communication exists over the first link for longer than a defined recovery interval, the type of reconfiguration event comprising a change in a node that is using the first link; and

detect a reconfiguration event of said type in the first optical connection while a connection exists over the first link before the defined recovery interval elapses; and

a processor coupled to the interface and operable to;

initiate a discovery process to detect whether the first node or a second node is using the first link; and

upon detecting a second node using the first link, disable the first optical connection and establish a second optical connection with the second node, wherein disabling the first optical connection comprises releasing at least one resource associated with the first optical connection to prevent stranding of the resource.

7. The system of claim 6, wherein the processor operable to establish the second optical connection comprises a processor operable to debounce the second optical connection.

8. The system of claim 6, wherein the communication protocol comprises Link Management Protocol (LMP) and the processor operable to initiate the discovery process comprises a processor operable to initiate an LMP discovery process.

9. The system of claim 6, wherein the processor is further operable to:

initiate a timer set to a recovery interval; and

upon lapse of the recovery interval without detection of the second node, transition a finite state machine associated with the first optical connection to a down state.

10. The system of claim 6, wherein the processor operable to detect a change in the first optical connection comprises a processor operable to transmit a link verification message.

11. A non-transitory computer readable medium, the non-transitory computer readable medium comprising code operable when executed to:

establish a first optical connection with a first node using a first link, wherein the first optical connection with the first node uses a communication protocol that is defined to detect a type of reconfiguration event in the first optical connection when no communication exists over the first link for longer than a defined recovery interval, the type of reconfiguration event comprising a change in a node that is using the first link;

detect a reconfiguration event of said type in the first optical connection while a connection exists over the first link before the defined recovery interval elapses;

initiate a discovery process to detect whether the first node or a second node is using the first link; and

upon detecting a second node using the first link, disable the first optical connection and establish a second optical connection with the second node, wherein disabling the first optical connection comprises releasing at least one resource associated with the first optical connection to prevent stranding of the resource.

12. The medium of claim 11, wherein the code operable to establish the second optical connection comprises code operable to debounce the second optical connection.

13. The medium of claim 11, wherein the communication protocol comprises Link Management Protocol (LMP) and the code operable to initiate the discovery process comprises code operable to initiate an LMP discovery process.

14. The medium of claim 11, wherein the code is further operable to:

initiate a timer set to a recovery interval; and

upon lapse of the recovery interval without detection of the second node, transition a finite state machine associated with the first connection to a down state.

15. The medium of claim 11, wherein the code operable to detect a change in the first optical connection comprises code operable to transmit a link verification message.