A router made up firstly of at least two router modules, only one of which is in an active state at any given time, and secondly a of changeover device making it possible to cause one of the other router modules to go from a standby state to an active state when the router module in the active state stops, and the router modules having state machines associated with each of the neighbor routers, wherein each of the router modules has a data storage device which, in the active state, enables it to store data relating to the states of the state machines, when the machines are in stable states, and a data retrieval device for retrieving the data when the router module changes over to the active state.