Switching router and a datagram transfer system

• US 6,252,853 B1
• Filed: 07/24/1998
• Issued: 06/26/2001
• Est. Priority Date: 07/24/1997
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ohno, Shuji
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US09/121,593
• Time in Patent Office: 1,068 Days
• Field of Search: 370/217, 370/225, 370/227, 370/242, 709/202
• US Class Current: 370/242
• CPC Class Codes: H04L 2012/5667 IP over ATM
• CPC Class Codes: H04L 49/251 Cut-through or wormhole routing
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/255 Control mechanisms for ATM switching fabrics
• CPC Class Codes: H04L 49/557 Error correction, e.g. fault recovery or fault tolerance
• CPC Class Codes: H04L 49/602 Multilayer or multiprotocol switching, e.g. IP switching

Abstract

A label switching router which includes a data relay controller for transferring IP datagrams and controlling the transfer, detecting any transfer IP datagram satisfying a particular condition, and controlling an ATM switch based on a detection result and an ATM switch for switching between adjacent nodes for transferring ATM cells. An operation state of the data relay controller is monitored and a user-specified VP route is set to the ATM switch according to a fault circumventing route table, thereby continuing communication between the adjacent nodes on both side of this ATM switch if a fault occurs on the data relay controller.

Claims

1. A switching router comprising:

plural line interfaces each of which connects to a network device;

a switching mechanism which switches connection among the line interfaces and performs datagram transfer among them; and

a relay controller which controls the switching mechanism such as normally transferring data through the relay controller and transferring data that satisfies a certain condition only through said switching mechanism by skipping the relay mechanism;

wherein the switching mechanism further includes

a relay controller monitoring means for monitoring an operation state of the relay controller and an alternate route setting means for setting an alternate route when the relay controller monitoring means detects a fault on the relay controller.

2. A switching router according to claim 1, wherein the alternate route setting means restores connection among the line interfaces in the switching mechanism in case that the relay controller monitoring means further detects normal operation of the relay controller.

3. A switching router according to claim 1, wherein the relay controller monitoring means includes a first table storing connection place of the relay controller and an operation state of the relay controller.

4. A switching router according to claim 3, wherein the connection place stored in the first table is a port number of the relay controller.

5. A switching router according to claim 3, wherein the connection place stored in the first table is a slot number of the relay controller.

6. A switching router according to claim 2, wherein the alternate route setting means includes second table storing current route and its alternative route in the switching mechanism and the alternate route setting means performs setting alternative route/restoring current route based on the second table.

7. A switching router according to claim 6, wherein the current route in the second table is described as port numbers of two adjacent nodes communicating via the relay controller and the alternate route in the second table is described as virtual path connection.

8. A datagram transfer system comprising:

first network device for sending datagram connecting first network;

second network device for receiving the datagram connecting second network;

a label switching router for connecting said first and second network, the label switching router comprising;

plural line interfaces for connecting said first and second network, and

a switching mechanism which switches connection among the line interfaces and performs datagram transfer among them; and

a relay controller which controls the switching mechanism such as normally transferring data through the relay controller and transferring data that satisfies a certain condition only through said switching mechanism by skipping the relay mechanism;

wherein the label switching router further includes

a relay controller monitoring means for monitoring an operation state of the relay controller and an alternate route setting means for setting an alternate route when the relay controller monitoring means detects a fault on the relay controller.

9. A datagram transfer system according to claim 8, wherein the alternate route setting means restores connection among the line interfaces in the switching mechanism in case that the relay controller monitoring means further detects normal operation of the relay controller.

10. A datagram transfer system according to claim 8, wherein the relay controller monitoring means includes a first table storing connection place of the relay controller and an operation state of the relay controller.

11. A datagram transfer system according to claim 10, wherein the connection place stored in the first table is a port number of the relay controller.

12. A datagram transfer system according to claim 10, wherein the connection place stored in the first table is a slot number of the relay controller.

13. A datagram transfer system according to claim 9, wherein the alternate route setting means includes second table storing current route and its alternative route in the switching mechanism and the alternate route setting means performs setting alternative route/restoring current route based on the second table.

14. A datagram transfer system according to claim 13, wherein the current route in the second table is described as port numbers of two adjacent nodes communicating via the relay controller and the alternate route in the second table is described as virtual path connection.

15. A data transfer method for a label switching router having plural of ports for connecting to adjacent nodes, switching mechanism for switching connections among the ports, and a data relay controller for controlling the switching mechanism, the method comprising the steps of:

monitoring an operation state of the data relay controller;

setting an alternate route for fault circumvention between specified ports when a wrong state of the data relay controller is detected by the monitoring step; and

deleting the alternate route for fault circumvention between specified ports and restore restoring connection among the ports when normal operation is detected by the monitoring step after the setting step.

16. A data transfer method for a label switching router having switching mechanism and plural of ports for connecting to adjacent node and a data relay controller for controlling the switching mechanism, the method comprising the steps of:

monitoring an operation state of the data relay controller;

setting an alternate route for fault circumvention between specified ports when a wrong state of the data relay controller is detected by the monitoring step; and

deleting the alternate route for fault circumvention between specified ports and restoring connection among the ports when normal operation is detected by the monitoring step after the setting step.

17. A computer program product stored on a computer readable medium for performing , when executed by a label switching router having plural of ports for connecting to adjacent nodes, switching mechanism for switching connections among the nodes and a relay controller for controlling the switching mechanism, the computer program product comprising:

monitoring an operation state of the data relay controller;

setting an alternate route for fault circumvention between specified ports when a wrong state of the data relay controller is detected by the monitoring step; and

deleting the alternative route for fault circumvention between specified ports and restoring connection among the ports when normal operation is detected by the monitoring step after the setting step.

18. A computer program product stored on a computer readable medium for performing , when executed by a label switching router having switching mechanism and plural of ports for connecting to adjacent node and a data relay controller for controlling the switching mechanism, the computer program product comprising:

monitoring an operation state of the data relay controller;

setting an alternate route for fault circumvention between specified ports when a wrong state of the data relay controller is detected by the monitoring step; and

deleting the alternate route for fault circumvention between specified ports and restoring connection among the ports when normal operation is detected by the monitoring step after the setting step.