Patent ID: 11968082
Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method performed by a first controller in a software defined networking (SDN) network to monitor a health of a second controller, the first controller and the second controller being part of a cluster of controllers, controllers in the cluster communicating with switches in the SDN network over an in-band network, and controllers in the cluster communicating with each other over an out-of-band network that is separate from the in-band network, the method comprising:
determining, by the first controller, that the second controller cannot be reached over the out-of-band network;
sending, by the first controller, a first control message to a switch over the in-band network in response to a determination that the second controller cannot be reached over the out-of-band network, the first control message including a health check request message and an instruction for the switch to send the health check request message to the second controller, and the switch being a designated switch that has a control channel connection to the first controller and the second controller over the in-band network;
determining, by the first controller, whether a health check acknowledgement message has been received from the switch, the health check acknowledgement message comprising an acknowledgement received by the switch from the second controller over the in-band network in response to the health check request sent by the switch to the second controller;
determining, by the first controller, that the out-of-band network has a failure in response to a determination that the health check acknowledgement message has been received from the second controller over the in-band network, the health check acknowledgement message being included in a second control message sent by the switch to the first controller over the in-band network;
configuring, by the first controller, the switch to establish a control channel connection to all controllers in the cluster;
receiving, by the first controller, a third control message from the switch over the in-band network, the third control message including a health check request message generated by a third controller in the cluster, the switch having a control channel connection to the third controller;
sending, by the first controller, a fourth control message to the switch over the in-band network in response to receiving the third control message, the fourth control message including a health check acknowledgement message and an instruction for the switch to send the health check acknowledgement message to the third controller; and
determining, by the first controller, that the second controller has a failure in response to a determination that the health check acknowledgement message has not been received from the second controller over the in-band network.