Notifying a Controller of a Change to a Packet Forwarding Configuration of a Network Element Over a Communication Channel

• US 20110317559A1
• Filed: 12/17/2010
• Published: 12/29/2011
• Est. Priority Date: 06/25/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Kern, Andràs, Jocha, Dàvid
• Granted Patent: US 8,897,134 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 41/0816 the condition being an adaptation, e.g. in response to network events
• CPC Class Codes: H04L 41/342 between virtual entities, e.g. orchestrators, SDN or NFV entities
• CPC Class Codes: H04L 45/02 Topology update or discovery

Abstract

A method performed by a network element, for notifying a controller of a change to a packet forwarding configuration of the network element. The network element is separated from the controller by a communication channel. The method includes determining the change to the packet forwarding configuration of the network element. The packet forwarding configuration specifies how packets are to be forwarded by the network element. The method also includes actively notifying the controller of the change to the packet forwarding configuration by sending a message to the controller over the communication channel. The message, in addition to indicating the change, also indicates at least one detail about the packet forwarding configuration after the change.

Claims

1. A method performed by a network element, for notifying a controller of a change to a packet forwarding configuration of the network element, where the network element is separated from the controller by a communication channel, the method comprising the steps of:

determining the change to the packet forwarding configuration of the network element, wherein the packet forwarding configuration specifies how packets are to be forwarded by the network element; and

actively notifying the controller of the change to the packet forwarding configuration by sending a message to the controller over the communication channel, the message in addition to indicating the change also indicating at least one detail about the packet forwarding configuration after the change.

2. The method of claim 1, further comprising:

receiving a packet forwarding configuration modification message from the controller over the communication channel, the packet forwarding configuration modification message specifying a modification to the packet forwarding configuration of the network element, and

wherein determining the change to the packet forwarding configuration comprises determining a change to the packet forwarding configuration that is different than the modification specified by the message.

3. The method of claim 2, wherein actively notifying the controller by sending the message comprises sending a message that includes:

one of;

(a) an identification of the packet forwarding configuration modification message; and

(b) the modification specified by the packet forwarding configuration modification message; and

a second packet forwarding configuration modification message, the second packet forwarding configuration modification message specifying the change to the packet forwarding configuration.

4. The method of claim 2, wherein actively notifying the controller by sending the message comprises sending a message indicating a reason for the change, the reason selected from a group consisting of:

(a) the packet forwarding configuration modification message was invalid;

(b) the packet forwarding configuration modification message was changed to improve performance of the network element; and

(c) the packet forwarding configuration modification message was translated by a virtualization entity.

5. The method of claim 1, further comprising:

the network element detecting a flow changing event within the network element, and

wherein determining the change includes the network element determining to change the packet forwarding configuration, without explicit instruction from the controller, based on the detection of the flow changing event.

6. The method of claim 5, wherein detecting the flow changing event comprises detecting that a port associated with a flow is unavailable, wherein determining the change includes determining a replacement port for the port that is unavailable, and wherein sending the message indicating the at least one detail includes sending a message indicating the replacement port for the flow.

7. The method of claim 1, wherein determining the change comprises determining the change based on information internal to the network element that is not available to the controller.

8. The method of claim 1, wherein determining the change to the packet forwarding configuration comprises determining a change to a flow table that includes flow entries, each flow entry including header fields, counters, and zero or more data forwarding actions to apply to a packet that matches the header fields, and wherein the at least one detail comprises a detail of a flow entry in the flow table after the change.

9. The method of claim 1, wherein actively notifying the controller is not in response to a query from the controller, wherein detecting the change comprises detecting a change that is not merely a deletion of a portion of the packet forwarding configuration, and wherein the detail comprises a detail of portion of the packet forwarding configuration after the change.

10. A network element, the network element operable to be coupled with a controller by a communication channel, the network element operable to notify the controller of a change to a packet forwarding configuration of the network element, the network element comprising:

an interface to the communication channel;

the packet forwarding configuration, wherein the packet forwarding configuration specifies how packets are to be forwarded by the network element;

a configuration change determination module, the configuration change determination module operable to determine the change to the packet forwarding configuration of the network element; and

a notification module, the notification module operable to notify the controller of the change to the packet forwarding configuration by sending a message to the controller over the communication channel through the interface, the message in addition to indicating the change also indicating at least one detail about the packet forwarding configuration after the change.

11. The network element of claim 10,

wherein the interface is operable to receive a packet forwarding configuration modification message from the controller over the communication channel, the packet forwarding configuration modification message operable to specify a modification to the packet forwarding configuration, and

wherein the configuration change determination module is operable to determine a change to the packet forwarding configuration that is different than the modification specified by the packet forwarding configuration modification message.

12. The network element of claim 11, wherein the notification module comprises a message generation module, the message generation module operable to generate a message to be sent that includes:

one of;

(a) an identification of the packet forwarding configuration modification message; and

(b) the modification specified by the packet forwarding configuration modification message; and

a second packet forwarding configuration modification message, the second packet forwarding configuration modification message specifying the change to the packet forwarding configuration.

13. The network element of claim 10, wherein the network element is operable to detect a flow changing event within the network element, and wherein the configuration change determination module is operable to determine to change the packet forwarding configuration, without explicit instruction from the controller, based on the detection of the flow changing event.

14. The network element of claim 13, wherein the network element is operable to detect that a port associated with a flow is unavailable as the flow changing event, wherein the configuration change determination module is operable to determine a replacement port for the port that is unavailable, and wherein the notification module is operable to indicate the replacement port in the message sent to the controller.

15. The network element of claim 10, wherein the packet forwarding configuration comprises a flow table that includes flow entries, each flow entry including header fields, counters, and zero or more data forwarding actions to apply to a packet that matches the header fields.

16. A method performed by a controller of a network element, for updating a record of a packet forwarding configuration of the network element that is maintained by the controller, where the controller is separated from the network element by a communication channel, the method comprising the steps of:

receiving a notification of a change to the packet forwarding configuration of the network element over the communication channel, wherein the packet forwarding configuration specifies how packets are to be forwarded by the network element, and wherein the notification, in addition to indicating the change, also indicates at least one detail about the packet forwarding configuration of the network element after the change; and

updating the record of the packet forwarding configuration to reflect the change.

17. The method of claim 16, further comprising the controller sending a message to the network element to request that the network element provide notification of changes to multiple packet forwarding configuration modification messages sent by the controller to the network element.

18. The method of claim 16, further comprising the controller sending a message to the network element to one of allow and deny changes to a packet forwarding configuration modification message sent from the controller to the network element.

19. A controller of a network element, the controller operable to be coupled with the network element by a communication channel, the controller operable to update a record of a packet forwarding configuration of the network element that is maintained by the controller, the controller comprising:

an interface to the communication channel, the interface operable to receive a notification of a change to the packet forwarding configuration of the network element from the communication channel, wherein the notification, in addition to indicating the change, also indicates at least one detail about the packet forwarding configuration of the network element after the change;

the record of the packet forwarding configuration of the network element, wherein the packet forwarding configuration specifies how packets are to be forwarded by the network element; and

an update module to update the record of the packet forwarding configuration to reflect the change indicated by the notification.

20. The controller of claim 19, further comprising a change authorization module that is operable to in one instance send a message to the network element to allow changes to a packet forwarding configuration modification message sent from the controller to the network element, and in another instance send a message to the network element to deny changes to a packet forwarding configuration modification message sent from the controller to the network element.

21. The controller of claim 19, further comprising a change notification request module that is operable to send a message to the network element to request that the network element provide notification of changes to multiple packet forwarding configuration modification messages sent by the controller to the network element.