1-3z The IP address of the virtual router can be either an unused IP address on the segment where theVRRP group resides or the IP address of an interface on a router in the VRRP group. In the lattercase, the router is called the IP address owner.z In a VRRP group, you can configure only one IP address owner.VRRP priorityVRRP determines the role (master or backup) of each router in the VRRP group by priority. A router witha higher priority has more opportunity to become the master.VRRP priority is in the range of 0 to 255. The greater the number, the higher the priority. Priorities 1 to254 are configurable. Priority 0 is reserved for special uses and priority 255 for the IP address owner.When a router acts as the IP address owner, its running priority is always 255. That is, the IP addressowner in a VRRP group acts as the master as long as it works properly.Working modeA router in a VRRP group works in one of the following two modes:z Non-preemptive modeWhen a router in the VRRP group becomes the master, it stays as the master as long as it operatesnormally, even if a backup is assigned a higher priority later.z Preemptive modeWhen a backup finds its priority higher than that of the master, the backup sends VRRP advertisementsto start a new master election in the VRRP group and becomes the master. Accordingly, the originalmaster becomes a backup.Authentication modeTo avoid being attacked by unauthorized users, VRRP authenticates the received packets by addingauthentication keys into the packets. VRRP provides two authentication modes:z simple: Simple text authenticationA router sending a packet fills an authentication key into the packet, and the router receiving the packetcompares its local authentication key with that of the received packet. If the two authentication keys arethe same, the received VRRP packet is considered real and valid; otherwise, the received packet isconsidered invalid.z md5: MD5 authenticationThe router encrypts a packet to be sent using the authentication key and MD5 algorithm and saves theencrypted packet in the authentication header. The router receiving the packet uses the authenticationkey to decrypt the packet and checks the validity of the packet.On a secure network, you do not need to set the authentication mode.VRRP TimersVRRP timers include VRRP advertisement interval timer and VRRP preemption delay timer.
