BGP session instability with Cogent in ZRH

タイムライン

1. 解決済み2024/07/27 19:45 UTC

   Stable since 19:45 UTC. Outbound traffic is back on its normal paths. Duration: 37 minutes. Impact was limited to brief latency spikes on some routes; no session to a machine was reset.

2. 監視中2024/07/27 19:36 UTC

   The session has been stable for 9 minutes. Traffic remains on Init7 while we watch.

3. 原因特定2024/07/27 19:18 UTC

   The resets coincide with a route-refresh storm on the Cogent side. We have applied dampening on our end and shifted outbound traffic to Init7 while Cogent investigates.

4. 調査中2024/07/27 19:09 UTC

   The BGP session with Cogent in ZRH has reset 7 times since 19:08 UTC. Each reset causes a few seconds of reconvergence for traffic that prefers that path. We are looking at our side of the session first.