Barber's Notes A route flap is any routing change that would cause a change in the BGP table. Large numbers of these at any one time is is a serious problem. At 30 updates per second, routing table updates are difficult. At 50 updates per second, HDLC doesn't happen. There is a daily cycle to the patterns.
Sprint notes that the problem probably originates from lines going up and down.
This needs to be fixed. Line changes appear to be the biggest problem. Many of these are single updates. Sean argues that doing BGP with customers is evil, especially if the customer injects alot of updates. Sean argues that the router closes to the problem should generate an unreachable.