The following events occurred
(Event) Wan peer disconnection between Primary Hub and multiple spoke locations
(Event) Wan peer disconnection between Primary Hub and multiple spoke locations (about 80 locations) In the journal log of primary Hub, there are large number of errors , indicating that some value of spoke was duplicated.
The trigger for the above peer down has been triggered by Bfd failure for these peers (Hold down timer expired for session: Bfd connInfo )
BFD is used to detect path failures between routers. BFD notifies the other peer-path observers when there is packet loss between peering routers, or if the link fails. In many cases it becomes critical to minimize session failovers to prevent the session from oscillating between paths, to reduce unnecessary changes to routing tables, prevent consumption of valuable system resources, and avert needless convergence impact. SSR routers have a hold down timer that can be configured to prevent BFD from making immediate updates until the timer has expired.
Parameters
Initial Hold Down Timer: The minimum amount of time BFD must wait before beginning notifications. The default is 5 seconds, and can be configured to be any value lower than the maximum-hold-down-time. The hold-down-timer will not accept a value of 0.
Maximum Hold Down Timer: The maximum amount of time that BFD must wait before it begins notifications. This timer only applies when BFD damping is enabled. The default value for this is 3600s (or 1 hour). The network administrator may configure this to be any value higher than the initial hold-down-time
BFD is used to detect path failures between routers. BFD notifies the load-balancer and other peer-path observers when there is packet loss between peering routers, or if the link fails