|  | 11.3 | Distance-Vector Routing
| 11.3.8 | The solution of hold-down timers
You can avoid a count to infinity problem by using hold-down timers that work as follows: When a router receives an update from a neighbor indicating that a previously accessible network is now inaccessible, the router marks the route as inaccessible and starts a hold-down timer. If at any time before the hold-down timer expires an update is received from the same neighbor indicating that the network is again accessible, the router marks the network as accessible and removes the hold-down timer. If an update arrives from a different neighboring router with a better metric than originally recorded for the network, the router marks the network as accessible and removes the hold-down timer. If at any time before the hold-down timer expires an update is received from a different neighboring router with a poorer metric, the update is ignored. Ignoring an update with a poorer metric when a hold-down timer is in effect allows more time for the knowledge of a disruptive change to propagate through the entire network.