Operation Manual – HAH3C S7500E Series Ethernet Switches Chapter 1 VRRP Configuration1-2Apparently, this approach to enabling hosts on a network to communicate with externalnetworks is easy to configure but it imposes a very high requirement of performancestability on the device acting as the gateway. A common way to improve systemreliability is to use more egress gateways, introducing the problem of routing among themultiple egresses.Virtual Router Redundancy Protocol (VRRP) is an error-tolerant protocol designed toaddress this problem through separating physical devices from logical devices.Deploying VRRP on multicast and broadcast LANs such as Ethernet, you can ensurethat the system can still provide highly reliable default links without changingconfigurations (such as dynamic routing protocols, route discovery protocols) when adevice fails and prevent network interruption due to a single link failure.There are two VRRP versions: VRRPv2 and VRRPv3. VRRPv2 is based on IPv4, whileVRRPv3 is based on IPv6. The two versions implement the same functions but providedifferent commands.1.1.2 VRRP Standby Group OverviewVRRP combines a group of switches (including a master and multiple backups) on aLAN into a virtual router called standby group.The VRRP standby group has the following features:z A virtual router has an IP address. A host on the LAN only needs to know the IPaddress of the virtual router and uses the IP address as the next hop of the defaultroute.z Every host on the LAN communicates with external networks through the virtualrouter.z Switches in the standby group elect the gateway according to their priorities. Oncethe master switch acting as the gateway fails, the other switches in the standbygroup elect a new gateway to undertake the responsibility of the failed switch, thusensuring that the hosts in the network segment can communicate with the externalnetworks uninterruptedly.
