VRRP is a routing fault-tolerant protocol, which can also be called backup routing protocol. All hosts in the local area network have set default routes. When the destination address sent by the host in the network is not in this network segment, the message will be sent to the external router through the default route, thus realizing the communication between the host and the external network.
When the default router is turned off (that is, the port is turned off), the internal host will not be able to communicate with the outside. If the router is set with VRRP, the virtual route will enable the backup router at this time, thus realizing full netcom communication.
VRRP terminology
1, virtual router
A virtual router is an abstract object based on subnet interface, including a virtual router identifier (VRID) and one or more IP addresses, also known as virtual IP addresses, which act as the default gateway for hosts.
2. VRRP router
A VRRP router is a router running the VRRP protocol, which can be added to one or more virtual routers.
3. IP address owner
The owner of the IP address, VRRP router, has the same virtual IP address as the real IP address of the interface.
4. Virtual router host
The virtual master router is responsible for forwarding the three-layer packets passing through the virtual router and responding to the ARP request of the IP address of the virtual router. If the VRRP router is the owner of the IP address, it is always the virtual master router.
5. Virtual router backup
The virtual backup router does not forward the three-layer data packet, does not answer the ARP request of the virtual IP address, and takes over the work of the virtual master router when the virtual master router fails.