Bug ID 1735105: Slot Failures and Split-Brain False Positives Caused by Clusterd Heartbeat Timeout Mismatch Between mgmt_bp and tmm_bp Interfaces

Last Modified: Jun 10, 2026

Affected Product(s):
BIG-IP LTM(all modules)

Known Affected Versions:
14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 14.1.3.1, 14.1.4, 14.1.4.1, 14.1.4.2, 14.1.4.3, 14.1.4.4, 14.1.4.5, 14.1.4.6, 14.1.5, 14.1.5.1, 14.1.5.2, 14.1.5.3, 14.1.5.4, 14.1.5.6, 15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 15.1.6.1, 15.1.7, 15.1.8, 15.1.8.1, 15.1.8.2, 15.1.9, 15.1.9.1, 15.1.10, 15.1.10.2, 15.1.10.3, 15.1.10.4, 15.1.10.5, 15.1.10.6, 15.1.10.7, 15.1.10.8, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3, 16.1.3.4, 16.1.3.5, 16.1.4, 16.1.4.1, 16.1.4.2, 16.1.4.3, 16.1.5, 16.1.5.1, 16.1.5.2, 16.1.6, 16.1.6.1, 17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3, 17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1, 17.1.2.2, 17.1.3, 17.1.3.1, 17.1.3.2, 17.5.0, 17.5.1, 17.5.1.2, 17.5.1.3, 17.5.1.4, 17.5.1.5, 17.5.1.6

Opened: Nov 13, 2024

Severity: 2-Critical

Symptoms

In a multi-bladed chassis, if one blade reboots or stops transmitting heartbeats, the other active blades may mistakenly mark themselves as SS_FAILED (Slot Failed) and turn RED. This can unintentionally trigger a high-availability (HA) failover if the number of active blades drops below the configured minimum threshold for up members.

Impact

When one healthy blade is disrupted, multiple other healthy blades may also fail simultaneously. This can lead to an unintended system failover and potential traffic disruption, depending on the high availability (HA) actions taken.

Conditions

This issue arises when a remote blade reboots or fails. During this time, a local blade stops receiving heartbeat signals from the cluster over the management backplane (mgmt_bp) interface. However, it continues to process the last remaining heartbeats via the Traffic Management Microkernel (TMM) backplane (tmm_bp) interface within the standard 10-second timeout window.

Workaround

If a blade transitions to SS_FAILED due to intermittent backplane communication issues, manually rebooting the affected blade or restarting the clusterd daemon can restore it to an SS_OK state once backplane connectivity is stable.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips