Operation Manual – VRRPH3C S5500-EI Series Ethernet Switches Chapter 1 VRRP Configuration1-4remains 255. That is, if there is an IP address owner in a standby group, it acts as themaster as long as it works properly.II. Working modeA switch in a standby group can work in one of the following two modes:z Non-preemption modeOnce a switch in the standby group becomes the master, it stays as the master as longas it operates normally, even if a backup switch is assigned a higher priority later.z Preemption modeOnce a backup switch finds its priority higher than that of the switch acting as themaster, it sends VRRP advertisements to start a new master switch election in thestandby group and becomes the master. Accordingly, the original master switchbecomes a backup.III. Authentication modeVRRP provides two authentication modes:z simple: Simple text authenticationYou can adopt the simple text authentication mode in a network facing possible securityproblems. A switch sending a packet fills the authentication key into the packet, and theswitch receiving the packet compares its local authentication key with that of thereceived packet. If the two authentication keys are the same, the received VRRPpacket is considered real and valid; otherwise, the received packet is considered aninvalid one.z md5: MD5 authenticationYou can adopt MD5 authentication in a network facing severe security problems. Theswitch encrypts a packet to be sent using the authentication key and MD5 algorithmand saves the encrypted packet in the authentication header. The switch receiving thepacket uses the authentication key to decrypt the packet and checks whether thepacket is valid.On a secure network, you need not set the authentication mode.1.1.3 VRRP TimersVRRP timers include VRRP advertisement interval timer and VRRP preemption delaytimer.I. VRRP advertisement interval timerThe master switch in a VRRP standby group sends VRRP advertisements periodicallyto inform the other switches in the standby group that it operates properly.
