Patent ID: 8442046

Claim:
A method comprising: receiving routing update data that indicates a change to link-state data from an updating node of a plurality of network nodes at a backup node; receiving election data and configuration data at the backup node, wherein the election data includes an identification of a designated node configured for propagating updated messages to the plurality of network nodes based on the routing update data received from the updating node, wherein the configuration data including a retransmission time for shifting from a multicast protocol to a unicast protocol for unresponsive network nodes; setting a re-flood time to a non-zero first value at the backup node; starting the retransmission time at the backup node; sending through an interface, an outbound single multicast data packet that includes the routing update data from the backup node to the plurality of nodes if a particular node's response to an updated message from the designated node is not received at the backup node within the re-flood time; and propagating a unicast message that includes the routing update data to each node in the plurality of network nodes that did not send a response to the outbound multicast data packet to the backup node within the retransmission time.