Dynamic control channel establishment for software-defined networks having centralized control

A network node comprising:

• one or more processors;
• one or more physical interfaces configured to send a plurality of hello messages to neighboring network nodes within a network, wherein each of the plurality of hello messages is sent on a different respective network link coupled to the network node and includes an indicator specifying a respective distance as a number of network hops from the network node to a centralized controller that manages the network,
• wherein the one or more physical interfaces receive a plurality of hello reply messages from respective neighboring network nodes within the network in response to the plurality of hello messages, wherein each of the plurality of hello reply messages is received on a different respective network link coupled to the network node and includes a respective indicator specifying a respective distance as a number of network hops from the respective neighboring network node sending the hello reply messages to a centralized controller that manages the network;
• and
• a protocol module executing on the one or more processors, wherein the protocol module is configured to determine, based at least in part on the respective distance specified by one or more of the plurality of hello reply messages received from the neighboring network nodes, an active one of the network links coupled to the network node to one of the neighboring network nodes having a shortest distance to the centralized controller,
• wherein the protocol module is configured to forward a discover message on the active link to the neighboring network node having the shortest distance to the centralized controller, wherein the discover message includes a neighbor node list specifying a set of neighboring network nodes from which hello reply packets were received and an intermediate node list that will specify a set of network nodes the discover message will traverse;
• and
• wherein the protocol module is configured to, after receiving a discover reply message sent by the centralized controller in response to the centralized controller receiving the discover message, send a control message to the centralized controller encapsulated with a MPLS label that indicates the control message is to be automatically forwarded by a receiving one of the network nodes along a shortest path toward the centralized controller.