IP Addresses and Services Configuration Guide for Cisco 8000 Series Routers, IOS XR Releases
IP Addresses and Services Configuration Guide for Cisco 8000 Series Routers, IOS XR Releases
This topic describes the HSRP preemption feature, which enables the router with the highest priority to immediately become the active router.
The HSRP preemption is an HSRP configuration feature that
allows the router with the highest priority to immediately become the active router
determines priority first by the priority value that you configure, and then by the IP address, and
manages state transitions through specific messaging.
The network architecture identifies the active router based on priority values, where the device with the higher value holds the primary position. If a higher-priority router joins the network, it assumes the active role by sending a coup message. The lower-priority active router receives this notification and relinquishes its position to ensure the most capable device manages traffic.
These stages describe the state transition process for HSRP preemption:
The system evaluates router priority based on the configured priority value and the IP address.
A higher-priority router sends a coup message to assert its status as the active device.
The lower-priority active router changes to the speak state and sends a resign message upon receiving a coup or hello message from a higher-priority router.