Bug ID 788557: BGP and BFD sessions are reset in GRST timeout period if bgpd daemon is restarted prior

Last Modified: Jul 12, 2019

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.5.4, 11.5.4 HF1, 11.5.4 HF2, 11.5.4 HF3, 11.5.4 HF4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 11.6.1, 11.6.1 HF1, 11.6.1 HF2, 11.6.2, 11.6.2 HF1, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 12.0.0, 12.0.0 HF1, 12.0.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 12.1.2 HF1, 12.1.2 HF2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4, 12.1.4.1, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.4, 14.1.0.5, 14.1.0.6, 15.0.0

Opened: May 30, 2019
Severity: 3-Major

Symptoms

GRST - BGP graceful reset. The problem occurs when the routing daemon bgpd restarts/starts (e.g., by terminating the bgpd daemon) its distribution of a process and is not supported. Another way we've found is to call "bigstart restart" command on a primary blade on chassis with more than one blade. After the new primary blade takes over, BGP and BFD sessions are recreated at around the 'graceful restart' timeout interval.

Impact

If BGP peering is reset, it causes the routing protocol to withdraw dynamic routes learnt by the configured protocol, making it impossible to advertise dynamic routes of affected routing protocol from the BIG-IP system to the configured peers. This can lead to unexpected routing decisions on the BIG-IP system or other devices in the routing mesh. In most cases, unexpected routing decisions come from networks learnt by affected routing protocol when the routing process on the BIG-IP system become unreachable. However, this state is short-lived, because the peering will be recreated shortly after the routing protocol restarts. The peering time depends on the routing configuration and responsiveness of other routing devices connected to the BIG-IP system, typically, the routing convergence period, which includes setting the peering and exchanging routing information and routes.

Conditions

-- BGP and BFD are configured. -- BGP router's 'graceful restart' option is configured, enabled (set to 120 by default). -- The bgpd daemon is terminated. Another way to trigger the issue is to run 'bigstart restart' on a primary blade on a chassis with more than one blade.

Workaround

None.

Fix Information

None

Behavior Change