How VRRP routing technology achieves routing redundancy and load balancing

The current VRRP routing technology is widely used. So I have studied how VRRP routing technology achieves routing redundancy and load balancing. I would like to share with you here and hope it will be useful to you. With the continuous development of network applications, users' demands for network reliability are getting higher and higher. Vrouters in the network run dynamic routing protocols such as RIP and OSPF to implement redundant backup of network routes. When a master route fails, the network can automatically switch to its backup route to achieve network connection.

However, it is not feasible to run a dynamic routing protocol on the host of the network edge end user to achieve reliability. Generally, an enterprise LAN connects to the Internet through a router, and the user host in the LAN can access the external network by configuring the default gateway. All hosts on the internal network are configured with a default gateway GW: 192.168.1.1), which is the router's E thernet0 interface address. In this way, packets sent from the Intranet host whose destination address is not in this segment will be sent to routethrough the default gateway, thus achieving communication between the host and the external network. Vrorouis a key device in the network. When a router fails, the LAN will interrupt Communication with the Internet. Applications for enterprises that rely on frequent network and external business exchanges, as well as the company's branches and headquarters, and the connection between banking outlets and bank data centers will be greatly affected.. To improve network reliability, A vro is usually added when the network is built.

However, if you only set multiple routers on the network without special configuration, the host can only send packets to the default gateway that is pre-configured for the target address as packets from other networks, however, the router cannot be automatically switched in case of a fault. VRRP routing technology vro redundancy protocol is designed to address the preceding backup problems and eliminate the inherent defects in the static default routing environment. It does not change the networking situation. You only need to configure a few commands on the relevant vro. In the case of network equipment failure, you do not need to make any configuration changes on the host, the next hop gateway can be backed up without any burden on the host.

VRRP Routing Technology Analysis VRRP (Virtua Router Redundancy Protoco) is AN access device fault tolerance protocol, VRRP routing technology organizes a group of routers in the LAN, including a Master, an active router, and several Backup routers, into a virtual router, called a Backup group.

VRRP routing technology organizes a group of routers, routors and RouterB in a LAN into a virtual router. The vro has its own IP address 192.168.1.3, which is called the virtual IP address of the vro. At the same time, physical routers, RouterB, and RouterB also have their own IP addresses. For example, RouterB's IP address is 192.168.1.1 and RouterB's IP address is 192.168.1.2 ). The host in the LAN only knows the IP address of the vro 192.168.1.3, but does not know the IP address of the specific vro in the backup group. During configuration, set the default gateway of the LAN host to the IP address 192.168.1.3 of the vro. As a result, the host in the Network communicates with other networks through this virtual router, and the actual data processing is performed by the Master router in the backup group. If the Master router in the Backup group fails, other Backup routers in the Backup group will replace the new Master and continue to provide routing services to the hosts in the network. In this way, the hosts in the network can communicate with the external network continuously. VRRP routing technology achieves redundancy through multiple routers. At any time, only one router is used as the primary router, and the other is the backup router. The switchover between routers is completely transparent to users. users do not have to worry about the specific process. You only need to set the default router as the IP address of the virtual router. The process of switching between Routers:

1. VRRP routing technology selects the primary router as the election method. Compare the priority of each vro. The Master vro with the highest priority changes to the Master status. If the router has the same priority, the primary IP address of the network interface is compared. If the primary IP address is large, the primary router provides the actual routing service.

2. After the primary router is selected, other routers act as the backup router, and monitor the status of the primary router through the VRRP route technical packet sent by the primary router. When the primary router is working normally, it sends a VRRP route technical group broadcast every other time to notify the backup router that the primary router is working properly. If the backup router in the group does not receive messages from the vro for a long time, the vro status is changed to Master. When there are multiple backup routers in the group, repeat the 1st step election process. In this process, the router with the highest priority is selected as the new primary router to implement the backup function of VRRP routing technology.

VRRP routing technology is used in VRRP Routing Technology of large-scale campus networks. It is not only used for the backup of routers connecting the LAN to the Internet, but also widely used for redundancy backup of layer-3 switches in the core layer of large-scale campus networks. In a large campus network, the core layer is in the center of the network, and a large amount of data is exchanged between the networks through the core layer equipment, while undertaking the routing function between different VAN. Once a device in the core layer goes down, the entire network is paralyzed. Therefore, in campus network design, the selection of core equipment requires strong data exchange capability and high reliability. Generally, the selection of high-end core layer-3 switches is required. At the same time, to further improve the reliability of the core layer and prevent the entire network from being paralyzed due to device downtime at the core layer, a device is usually placed at the core layer as a backup for another device, once the master device fails, switch to the slave device immediately to ensure high reliability of the network core layer.

VRRP routing technology is required for switching layer-3 switches in the core layer. To improve network reliability, two layer-3 switches S1 and S2 are deployed on the core layer of the network ,... And SWn) connect two core switches respectively. In a large campus network, to suppress broadcast signals, improve network performance, and achieve secure access control of the network, the entire network is generally divided into multiple different VAN according to the specific situation, the default gateway of the host in v an is set to the VAN interface address on the layer-3 switch.