In hot standby networking, if the upstream and downstream devices run BGP, you are advised to run the undo dampening (BGP) command to disable route suppression on the upstream and downstream devices. Active/standby switchover may cause route flapping. If route suppression is enabled, the device suppresses such routes and does not add them to the BGP routing table or advertise them to other BGP peers.
In hot standby networking, if a link is faulty and the BGP neighbor relationship fails to be established, the preemption delay of the VGMP group shall be greater than the neighbor establishment time. Otherwise, the service may be interrupted. The default preemption delay is 60 seconds. You can use the hrp preempt delay interval command to set the preemption delay. Setting the preemption delay of a VGMP group to 300s is recommended.
When BGP routes are imported to OSPF, as the default preference of BGP routes is lower than that of OSPF routes, the imported BGP routes do not take effect if there are same OSPF and BGP routes. To make the imported BGP routes take effect, run the preference command to increase the preference of BGP routes.