About Cisco HSRP

About Cisco HSRP
HSRP: The Hot Backup Router Protocol (HSRP) is designed to support the failure of IP traffic transfer under certain circumstances, which will not cause confusion and allow the host to use a single router, and maintain the connectivity between routers even if the first hop router fails to be used. In other words, when the source host cannot dynamically know the IP address of the First-hop router, The HSRP protocol can protect the first-hop router from failure. ------------ Copied from Baidu. In my opinion, redundancy means that a link is disconnected or the uplink is down and switched to the backup link. When the primary link returns to normal, data is still taken from the primary link. Experiment topology: You can view the topology on the image. Note the following key points: 1. preempt enables preemption. When the master link is down, the priority of the master link is reduced by 10, and the backup link is preemptible. Become active. The higher the priority, the higher the priority. track is used to monitor the uplink. When the uplink goes down for example, if the uplink goes down, the priority will be automatically reduced even if the downlink goes down to step 0/0, so that the backup link becomes active) both priority and track are configured in interface mode.