Keeping a BGP session healthy
A BGP session that keeps dropping and recovering is worse than one that is cleanly down — every flap churns the routing table. Stable sessions are the goal.
Why sessions flap
A flapping session is usually a symptom: a flapping link underneath, a congested or lossy path, or mismatched timers. Each time it drops, every route it carried is withdrawn and relearned, rippling outward. Find the physical or path cause first — the BGP layer is reporting it, not causing it.
Timers and limits
Hold timers decide how fast a dead session is noticed; set them sanely on both ends. A maximum-prefix limit protects you from a neighbour that suddenly announces far too many routes — the session drops deliberately rather than your router falling over. Route dampening can tame a chronically unstable prefix, used with care.
Reading the state
When routing wobbles, check the session state and the prefix counts on both sides, and use the looking glass to see how the wider internet sees your routes. We watch our side of every session and will dig into yours with you — see routing problems and keep your filters current.
Still stuck? Mail support@novogara.com — an engineer answers, at any hour. Back to the knowledge base