1. VRRP (Virtual Router Redundancy Protocol) adds the routers that can take on the gateway function into the backup group to form a virtual router. The election mechanism of VRRP determines which router takes on the forwarding task, and hosts in LAN only need to configure the virtual router as the default gateway.
2. VRRP is a fault-tolerant protocol, which improves reliability and simplifies the host configuration. In a local area network (such as Ethernet) with multicast or broadcast capability, VRRP can still provide a highly reliable default link when a certain device fails, effectively avoiding the problem of network interruption after a single link fails, without modifying configuration information such as dynamic routing protocol and route discovery protocol.
3. The VRRP protocol is implemented in two versions: VRRPv2 and VRRPv3. VRRPv2 is based on IPv4 and VRRPv3 is based on IPv6.
4. VRRP router: All routers running the VRRP protocol are called VRRP routers.
5. VRRP Backup Group: Multiple routers are divided into groups, in which one main router is selected and the others are used as backup routers. Usually, one of the main routers works, and the backup router is idle. When the main router fails, one of the backup routers is selected to replace the failed main router. Routers in this group form a backup group.
As shown in the figure below, there are two routers and two gateways. One of the two routers is selected as the primary router, and the others are backup routers. The primary router is responsible for forwarding datagrams, while the backup router is in an idle state. When the primary router fails, the backup router will become the primary router, replacing the primary router to realize the forwarding function.
6. Virtual router: A virtual router is a collection of all routers in a VRRP backup group. It is a logical concept and does not really exist. Looking at the routers in the backup group from the outside of the backup group, I feel that all the routers in the group are just like one. You can understand that they are in a group: master router + all backup routers = virtual routers. The virtual router has a virtual IP address and MAC address. If the virtual IP is the same as the IP of a router in the backup group, then this router is called the IP address owner and acts as the main router in the backup group.
As shown in the figure below: RA, RB and RC are VRRP routers, which form a VRRP backup group. RA is the main router, while RB and RC are backup routers. These three routers look like one from the outside, thus forming a virtual router Router Group. The virtual router has a virtual IP address of 10.1.1.1 (the IP of the main router of RA). RA is the owner of the IP address and the main router.
Please visit E-Lins Technology for more information.
