An election process takes place, where the primary router is elected. Only one device will be elected as the primary router. It will receive and forward packets destined for the Group IP. At the same time, a standby router is elected. It will monitor if the primary router is still reachable and if the active router fails, the standby router takes over and a new router is elected to be the standby router.
The router with the highest priority will be elected as the primary router. The default priority or all routers is 100. In case of a tie, the router with the highest IP Address will becom the primary router.