Notifying a controller of a change to a packet forwarding configuration of a network element over a communication channel

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 and specifies to which ports of the network element the packets are to be forwarded;
• a configuration change determination module coupled with the packet forwarding configuration, the configuration change determination module operable to determine the change to the packet forwarding configuration of the network element;
• and
• a notification module coupled with the configuration change determination 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 a portion of the packet forwarding configuration after the change, wherein the at least one detail comprises a detail of a flow entry in the flow table after the change, wherein each flow entry includes header fields, counters, and zero or more data forwarding actions to apply to a packet that matches the header fields, and wherein the message containing the detail of the flow entry after the change is sent to the controller without explicit instruction from the controller.

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:

• 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 a portion of the packet forwarding configuration of the network element after the change, wherein the at least one detail comprises a detail of a flow entry in the flow table after the change, wherein each flow entry includes header fields, counters, and zero or more data forwarding actions to apply to a packet that matches the header fields, and wherein the message containing the detail of the flow entry after the change is sent to the controller without explicit instruction from the controller;
• and
• updating the record of the packet forwarding configuration to reflect the change, wherein the controller is to maintain the record of the packet forwarding configuration of the network element including to which ports of the network elements the packets are to be forwarded.

An OpenFlow controller of a network element, the OpenFlow controller operable to be coupled with the network element by a communication channel, the OpenFlow controller operable to update a record of a packet forwarding configuration of the network element that is maintained by the OpenFlow controller, the OpenFlow 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 a portion of the packet forwarding configuration of the network element after the change, wherein the at least one detail comprises a detail of a flow entry in the flow table after the change, wherein each flow entry includes header fields, counters, and zero or more data forwarding actions to apply to a packet that matches the header fields, and wherein the message containing the detail of the flow entry after the change is sent to the controller without explicit instruction from the controller;
• 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 coupled with the record of the packet forwarding configuration to update the record of the packet forwarding configuration to reflect the change indicated by the notification.