system architectures and protocols are described to synchronize forwarding state across redundant control planes in a computer network . clusters of network devices include multiple agents , which are either in active or inactive mode . each such agent is associated with a forwarding information base , which stores network path information for communicating with network destinations . updates to the forwarding information bases are shared amongst the agents in a cluster by use of a network communications protocol . the protocol includes features that ensure that the active / inactive status of agents can be changed immediately , and that the fibs in a cluster are consistent at all times , in order to ensure that network forwarded by a cluster will not be disrupted in the event of a failure of an active agent . agents may be designated as either masters or slaves , which determines which determines the hierarchy in which fib entries and written to and read by agents .