Label switch network system

• US 20010019554A1
• Filed: 03/05/2001
• Published: 09/06/2001
• Est. Priority Date: 03/06/2000
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nomura, Yuji, Chugo, Akira
• Granted Patent: US 7,035,259 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: H04L 45/502 Frame based
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/602 Multilayer or multiprotocol switching, e.g. IP switching

Abstract

The present invention relates to label switch networks and allows for reducing the processing cost and processing time required at each node when various services are performed with respect to traffic engineering in the label switch networks including a multi-protocol label switching (MPLS) network. In a label switch network system a first node that is disposed at the ingress of the label switch network transfers IP packets corresponding to IP flows based on labels, and that selects and sets up layer 2 paths for transferring the IP packets with reference to header or payload information of the IP packets. A plurality of second nodes may be disposed at intermediate points of the network and they set up the layer 2 paths from the ingress to the egress of the network following the specified routes and a third node is disposed at the egress of the network. A policy server instructs the first node to set up the layer 2 paths in compliance with policy control protocols when a user makes a request or a status change in the network arise, and intensively controls the first node, the second nodes and the third node.

Claims

1. A label switch network system having a plurality of label switch nodes interconnected by network links where layer 2 paths are set up by specified routes between the plurality of label switch nodes from a network ingress to a network egress, comprising:

an ingress node which is disposed at the ingress of the label switch network that transfers packets corresponding to packet flows based on labels, and which selects and sets up layer 2 paths for transferring the packets with reference to the header or payload information of the packets;

a policy server that instructs the ingress node to set up the layer 2 paths in compliance with policy control protocols when at least one of a user makes a request or a status change in the network arises, and controls the ingress node and the plurality of label switch nodes.

2. The label switch network system according to

claim 1

, wherein the policy server comprises:

a unit for detecting the user request and the status change in the network,

a unit for determining, when transferring the packets in the ingress node, whether existing layer 2 paths are selected to transfer the packets or new layer 2 paths following appropriate routes are to be newly set up, and

a unit for calculating appropriate routes for the layer 2 paths including quality assurance parameters.

3. The label switch network system according to

claim 1

, wherein the ingress node comprises:

a unit for notifying the policy server of the user request or the status change in the network when at least one of the ingress node itself detects the user request or the status change in the network and the ingress node collects the user request or the status change in the network from any of the plurality of label switch nodes; and

the policy server comprises;

a unit for instructing the ingress node to set up the layer 2 paths for transferring the packets corresponding to newly generated packet flows, in response to notices sent by the ingress node.

4. The label switch network system according to

claim 1

, wherein each of the plurality of label switch nodes comprises:

a unit for routing the packets, and a unit for setting up the layer 2 paths passing through routes specified by IP addresses contained in the packets; and

the policy server comprises;

a unit for specifying one of the plurality of label switch nodes through which a layer 2 path will pass through in accordance with the IP address corresponding to the one of the label switch nodes.

5. The label switch network system according to

claim 1

, wherein when a plurality of the layer 2 paths exist through which packet flows can pass, new packet flows are generated based on a user request or a detected status change in the network, and

the policy server has a unit that responds to resource utilization conditions of each physical line as collected beforehand, by searching for routes that will keep the resource utilization conditions of each physical line balanced when adding the new packet flows, and a unit for instructing the ingress node to set up the layer 2 paths that can communicate the new packet flows generated in response to the user request or the detected status change in the network.

6. The label switch network system according to

claim 1

, wherein the ingress node comprises:

a unit for collecting and managing utilization conditions of the layer 2 paths, and

a unit for selecting from among a plurality of layer 2 paths through which certain packet flows can pass, the layer 2 paths appropriate for transferring the certain packet flows based on the utilization conditions of the plurality of the layer 2 paths.

7. The label switch network system according to

claim 6

, wherein the policy server detects newly generated packet flows generated in response to a user request or a status change in the network, and the policy server comprises:

a unit for instructing the ingress node to set up a plurality of the layer 2 paths which transfer the newly generated packet flows, and

a unit for instructing the ingress node to select the layer 2 paths appropriate for either the packets or the packet flows as a unit so that transferring the new packet flows will not cause any imbalance in the utilization conditions of the plurality of layer 2 paths with each other.

8. The label switch network system according to

claim 1

, wherein when a plurality of the layer 2 paths exist through which packet flows can pass, new packet flows are generated by a user request or a detected status change in the network, and the policy server has a unit for searching for at least two different routes for new layer 2 paths to transfer the new packet flows, for generating the new layer 2 paths for transferring the new packet flows, and for designating one of the new layer 2 paths as a working path and the other as a spare path in accordance with resource utilization conditions of each physical line as collected beforehand, and has a unit for instructing the ingress node to switch from the working path to the spare path, based on a judgment at one of the plurality of the label switch nodes when said one of the plurality of the label switch nodes detects a failure in the working path, and

the ingress node has a unit for switching the working path to the spare path when the ingress node itself detects a failure in the working path.

9. The label switch network system according to

claim 8

, wherein the policy server has a unit for instructing the ingress node to use the spare path for other traffic when the working path is normally operating, and to stop the other traffic from using the spare path and to make the spare path accommodate traffic which the workingpath was carrying when a failure arises in the working path.

10. The label switch network system according to

claim 1

, wherein one of the layer 2 paths can transfer packets corresponding to a plurality of different packet flows, and wherein the policy server and the plurality of label switch nodes each have

a unit for defining logical groups to which a plurality of packet flows belong and group identifiers for identifying the groups thereof, and

a unit for specifying the plurality of packet flows belonging to the group by the group identifiers when one of the layer 2 paths is switched;

and

the policy server has a unit for giving instruction to the ingress node so that packet flows and the layer 2 paths match with each other, making use of the group identifiers when one of the layer 2 paths is switched.

11. A policy server providing centralized management for a label switch network system having a plurality of label switch nodes interconnected by network links where layer 2 paths are set up by specified routes between the plurality of label switch nodes from a network ingress to a network egress, and

an ingress node disposed at the ingress of the label switch network that transfers packets corresponding to packet flows based on labels, and which selects and sets up layer 2 paths for transferring the packets with reference to the header or payload information of the packets;

the policy server comprising;

a receive processing unit for detecting requests or status changes in the network, and

a path creation and transmitting unit responsive to the receive processing unit, for instructing the ingress node to set up the layer 2 paths in compliance with policy control protocols, via the plurality of label switch nodes.

12. The policy server of

claim 11

, further comprising:

a unit for determining, when transferring the packets in the ingress node, whether existing layer 2 paths are selected to transfer the packets or new layer 2 paths following appropriate routes are to be newly set up, and

a unit for calculating appropriate routes for the layer 2 paths including quality assurance parameters.

13. The policy server of

claim 11

, wherein the ingress node notifies the policy server of the user request or the status change in the network, and

the policy server further comprising:

a unit for instructing the ingress node to set up the layer 2 paths for transferring the packets corresponding to newly generated packet flows, in response to notices sent by the ingress node.

14. The policy server of

claim 11

, wherein the packets are IP packets and contain IP addresses, and

the policy server comprises:

a unit for specifying one of the plurality of label switch nodes through which a layer 2 path will pass through in accordance with the IP address corresponding to the one of the label switch nodes.

15. The policy server of

claim 11

, wherein the packets are IP packets and a plurality of the layer 2 paths through which IP flows can pass exist, new IP flows are generated based on a user request or a detected status change in the network, and

the policy server further comprises:

a unit that responds to resource utilization conditions of each physical line as collected beforehand, for searching routes that will keep the resource utilization conditions of each physical line balanced when adding the new IP flows, and

a unit for instructing the ingress node to set up the layer 2 paths that can transfer the new IP flows generated in response to the user request or the detected status change in the network.

16. The policy server of

claim 11

, wherein the policy server detects newly generated packet flows generated based on a user request or a status change in the network, and the policy server further comprises:

a unit for instructing the ingress node to set up a plurality of the layer 2 paths which transfer the newly generated packet flows, and

a unit for instructing the ingress node to select the layer 2 paths appropriate for either the packets or the packet flows as a unit so that transferring the new packet flows will not cause any imbalance in the utilization conditions of the plurality of layer 2 paths with each other.

17. The policy server of

claim 11

, wherein when a plurality of the layer 2 paths exist through which packet flows can pass, new packet flows are generated by a user request or a detected status change in the network, and the policy server further comprises:

a unit for searching for at least two different routes for new layer 2 paths to transfer the new packet flows, for generating the new layer 2 paths for transferring the new packet flows, and for designating one of the new layer 2 paths as a working path and the other as a spare path in accordance with resource utilization conditions of each physical line as collected beforehand, and

a unit for instructing the ingress node to switch from the working path to the spare path, based on a judgment of at one of the plurality of the label switch nodes when the at one of the plurality of the label switch nodes detects a failure in the working path.

18. The policy server of

claim 17

, further comprises:

a unit for instructing the ingress node to use the spare path for other traffic when the working path is normally operating, and to stop the other traffic from using the spare path and to make the spare path accommodate traffic which the working path was carrying when a failure arises in the working path.

19. The policy server of claims 11, wherein the packets are IP packets, and the policy server further comprises:

a unit for defining logical groups, having group identifiers, to which a plurality of IP flows belong when one of the layer 2 paths transfers the IP packets corresponding to a plurality of different IP flows,

a unit for specifying the plurality of IP flows belonging to the group by the group identifiers when one of the layer 2 paths is switched, and

a unit for giving instruction to the ingress node so that IP flows and the layer 2 paths match with each other, using the group identifiers when one of the layer 2 paths is switched.

20. A method for setting up and selecting layer 2 paths for transferring IP packets in a label switch network system having a plurality of label switch nodes interconnected by network links where layer 2 paths are set up by specified routes between the plurality of label switch nodes from a network ingress to a network egress, and an ingress node disposed at the ingress of the label switch network system that transfers the IP packets corresponding to IP flows based on labels;

the method comprising the steps of;

detecting requests and status changes in the network,

determining, when transferring the IP packets in the ingress node, whether existing layer 2 paths are selected to transfer the IP packets or new layer 2 paths following appropriate routes are to be newly set up,

calculating appropriate routes for the layer 2 paths including quality assurance parameters,

instructing the ingress node to set up the layer 2 paths in compliance with policy control protocols, and

transferring the IP packets with reference to the header or payload information of the packets.

21. The method of

claim 20

, further comprising the steps of:

notifying a policy server of the user request or the status change in the network, and

in the policy server, instructing the ingress node to set up the layer 2 paths for transferring the IP packets corresponding to newly generated IP flows, in response to the notifying step.

22. The method of

claim 21

, further comprising the step of:

in the policy server, specifying one of the plurality of label switch nodes through which a layer 2 path will pass through in accordance with an IP address corresponding to the one of the label switch nodes.

23. The method of

claim 21

, further comprising the steps of:

generating new IP flows based on a user request or a detected status change in the network,

balancing resource utilization conditions of each physical line by searching for routes that will keep the resource utilization conditions of each physical line balanced when adding the new IP flows when a plurality of the layer 2 paths exist through which IP flows can pass, and

instructing the ingress node to set up the layer 2 paths that can transfer the new IP flows generated.