Fault recovery system and transmission path autonomic switching system

• US 6,122,753 A
• Filed: 04/08/1998
• Issued: 09/19/2000
• Est. Priority Date: 04/09/1997
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Iwata, Atsushi, Masuo, Hitoshi
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): Weir, James G.
• Application Number:
  US09/056,866
• Time in Patent Office: 895 Days
• Field of Search: 714/4, 713/153, 370/216, 370/217, 370/218, 370/221, 370/225, 370/228
• US Class Current: 714/4.2
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability
• CPC Class Codes: H04L 2012/5621 Virtual private network [VPN]; Private-network - network-interface (P-NNI)
• CPC Class Codes: H04L 2012/5627 Fault tolerance and recovery
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

Setting of a bypass path upon occurrence of transmission failure, is applicable for large scale network. A system includes signaling means which makes judgment whether bypassing process is performed by an own node by a bypassing process judgement means when a release message issued upon occurrence of failure, is received. Upon judgment to perform bypassing process, computation of bypass path is requested by the path computing means. On the basis of result of computation, bypass path is established and switched. In the bypassing process judgment means, judgment is made whether bypassing process is performed by the signaling means or not depending upon the relationship of positions of the faulty portion and the own node.

Claims

1. A fault recovery system in a connection oriented network employing a protocol establishing line connection using a source routing system which performs path computation on the basis of a topology information exchanged between nodes, for establishing a path bypassing a failure upon occurrence of failure in connection used in said network,

said nodes comprising:

first release message receiving means for receiving a release message generated upon occurrence of failure;

bypassing process judgment means for making judgment whether a bypassing process is primarily performed by a first node or not, depending upon a relationship of positions of a faulty portion, indicated in said release message, and said first node;

path computing means for performing path computation excluding said faulty portion when said bypassing process judgment means makes judgment that said bypassing process, in which said first node becomes a master, is to be performed;

setup message transmitting means for transmitting a setup message added an information of said faulty portion, for establishing a bypass path on the basis of bypass path information obtained by said path computing means when said bypassing process judgment means makes judgment that said bypassing process, in which said first node becomes a master, is to be performed;

switching means for performing switching by connecting said bypass path established by said setup message and a path in a direction toward a terminal not causing failure from said first node; and

first release message transmitting means for abandoning said release message in responsive to completion of switching by said switching means, and for transmitting said release message in a direction toward a terminal when switching is not completed.

2. A fault recovery system as set forth in claim 1, wherein said nodes further comprise:

second release message transmitting means, provided in place of said first release message transmitting means, for transmitting a release message with information indicative of on going state of switching by adding a content that said first node is in process for switching, to said release message when said release message is received, and transmitting a result message indicative of the result of switching process by said switching means of said first node; and

second release message receiving means for receiving said release message with the information indicative of on going state of switching or said result message,

said switching process being performed by computing a bypass path by said path computing means for preparation to switching upon reception of said release message with the information indicative of on going state of switching, transmitted from other node, and upon reception of said result message indicating that switching is not completed.

3. A fault recovery system in a connection oriented network employing a protocol establishing line connection using a source routing system which performs path computation on the basis of a topology information exchanged between nodes, for establishing a path bypassing a failure upon occurrence of failure in connection used in said network,

said nodes comprising:

first setup message receiving means for receiving a release message generated upon occurrence of failure or a setup message added information of a faulty portion;

bypassing process judgment means for making judgment whether a bypassing process is to be primarily performed by a first node or not depending upon a relationship of positions of a faulty portion indicated in said received message and said first node;

a timer to be triggered when said release message is received and said setup message is node received and stopped upon reception of said setup message;

connection state judgment means for making judgment whether a connection, in which failure is caused, is remained in said first node when said timer is not time out and said setup message is received;

switching means for performing switching by connecting said bypass path established by said setup message and a path in a direction toward a terminal not causing failure from said first node when said connection state judgment means makes judgment that the connection causing failure is remained; and

third release message transmitting means for transmitting said release message in responsive to time out of said timer, and for abandoning said release message when said timer is not cause time out.

4. A fault recovery system as set forth in claim 3, wherein said nodes further comprises fourth release message transmitting means for transmitting the release message to the path in a direction of occurrence of failure of connection where failure is caused when switching by said switching means is completed.

5. A fault recovery system as set forth in claim 3, wherein an address of a node, to which a destination terminal of connection is connected, is held upon establishing a connection demanded from a calling terminal.

6. A fault recovery system as set forth in claim 5, wherein a plurality of switching portions for switching failure upon occurrence of failure of connection are provided and reconnection is established with the destination terminal, to which connection is established before occurrence of failure.

7. A fault recovery system in a connection oriented network employing a protocol establishing line connection using a source routing system which performs path computation on the basis of a topology information exchanged between nodes, for establishing a path bypassing a failure upon occurrence of failure in a multi-point connection for establishing connection for a plurality of terminals,

said nodes comprising:

management judgment means for making judgment whether management of terminals involved in multi-point connection under management of a first node, upon setting of multi-point connection;

a database storing a management information when judgment is made that management is to be performed by said management judgment means;

notifying means for notifying a management information of said database to nodes to be candidate for performing management of other terminals involved in multi-point;

bypassing process judgment means for making judgment whether a bypassing process is to be performed by said first node or not depending upon a relationship of positions of a faulty portion and said first node;

path computing means for performing path computation excluding said faulty portion for connection managed by said first node on the basis of information held in said database when said bypassing process judgment means makes judgment that said bypassing process is to be performed;

path establishing means for establishing the bypass path on the basis of the bypass path information obtained by said path computing means when bypassing process is to be performed by said bypass process judgment means; and

switching means for performing switching between said bypass path and said path where failure is caused.

8. A fault recovery system as set forth in claim 7, wherein said nodes recover multi-point connection, in which failure is caused by said path computing means, said path establishing means and said switching means on the basis of information of said database when judgment is made to perform management by said management judgment means, in response to reception of message for bypass path setting.

9. A fault recovery system as set forth in claim 7, wherein said management judgement means makes judgement to perform management of the terminal involved in multi-point under management of said first node, when said first node is the node closest to the calling terminal on the connection in a node group as a predetermined local management unit.

10. A fault recovery system as set forth in claim 7, wherein said bypass process judgment means makes judgment to perform said bypass process when said first node is a starting point node or when said first node is located between said faulty portion and said calling terminal.

11. An autonomic switching system of transmission path in a connection oriented communication network using a protocol performing line connection using a source routing system performing path computation on the basis of topology information exchanged between nodes, wherein said nodes comprise:

demanded quality holding means for holding demanded quality information having a predetermined range of quality demanded by a terminal upon setting of connection;

path computing means for computing bypass path having a quality within a demanded quality range held by said demanded quality holding means in response to occurrence of connection failure; and

switching means for switching to a bypass path obtained by said path computing means.

12. An autonomic switching system of transmission path as set forth in claim 11, wherein said nodes further comprise means for retrieving a path having better quality than the path on use within a range of quality demanded by said terminal by triggering said path computing means at every predetermined period, to switch the retrieved oath by said switching means when path can be retrieved.

13. An autonomic switching system of transmission path as set forth in claim 11, wherein said quality is an information indicative of transmissible band of the path.