Operation Manual – VRRPH3C S5600 Series Ethernet Switches Chapter 1 VRRP Configuration1-4You can also set the preemption delay for an S5600 switch.Setting a delay period aims at:z In an unstable network, backups in a VRRP group possibly cannot receive VRRPadvertisements from the master in time due to network congestions. In this case,the backup considers itself as the master and sends out VRRP advertisements toelect master. This causes the master of the VRRP group to be determinedfrequently.z With preemption delay configured, if a backup does not receive VRRPadvertisements from the master in time, it waits for a while before switching to anew master. The backup does not send VRRP advertisements if it receives VRRPadvertisements from the master during the specified delay period.III. Authentication type and authentication key of a switch in a VRRP groupVRRP provides the following authentication types:z simple: Simple text authentication. In a network under possible security threat, theauthentication type can be set to simple. With the simple authentication typeconfigured, the switch adds an authentication key into a VRRP packet beforetransmitting it. The receiver then compares the authentication key of the packetwith the locally configured one. If they are the same, the packet will be taken as atrue and legal one. Otherwise it will be regarded illegal and discarded.z md5: MD5 authentication. In a vulnerable network, the authentication type can beset to md5. The switch then uses the authentication type provided in theAuthentication Header and the local MD5 algorithm to authenticate the VRRPpackets. Packets that fail to pass the authentication are discarded. The switchthen sends trap messages to the NMS.1.1.2 Virtual Router OverviewI. VRRP group and virtual router IP address configurationTo create a VRRP group, you need to configure an IP address for the VRRP groupvirtual router. The VRRP group is automatically created after you configure the first IPaddress for the VRRP group virtual router. Other IP addresses configured for the virtualrouter after this one are just added to the IP address list of the virtual router.The virtual router IP address has the following features:z The IP address of the virtual router can be an unassigned IP address in thenetwork segment where a member switch of the VRRP group resides.z You can specify the virtual router IP address as the IP address used by a memberswitch in the VRRP group. In this case, the member switch is called an IP addressowner.
