Bug ID 978953: The value of the sys db variable vlan.backplane.mtu intermittently out-of-sync with the value of the MTU of the kernel interface tmm_bp during the initial boot up

Last Modified: Jan 08, 2021

Bug Tracker

Affected Product:  See more info
BIG-IP All(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

Opened: Jan 06, 2021
Severity: 3-Major

Symptoms

During the initial boot of the device the MTU of the tmm_bp kernel interface is out-of-sync with the value of sys db vlan.backplane.mtu as well as out-of-sync with the MTU displayed by the following command: tmsh show /net vlan all-properties -hidden. tmsh list net vlan tmm_bp all-properties -hidden. Additionally, running the following command: modify sys db vlan.backplane.mtu value <some value> (within the range accepted), and saving the configuration change does not last through a reboot.

Impact

When the values are seen at non-sync, after the modification of the backplane vlan mtu and saving the config, changing the mtu config value does not last through a reboot.

Conditions

This issue occurs on the first boot intermittently.

Workaround

Rebooting the device resolves the issue

Fix Information

None

Behavior Change