A BIG-IP Administrator creates a new VLAN on BIG-IP Cluster Member A and attaches an Interface to it. Although the Auto Config Sync is in place, the new VLAN does NOT show up on Cluster Member B…

In an F5 BIG-IP High Availability (HA) cluster, while logical network objects like VLAN definitions (name, ID, tag) can be synchronized via Config Sync, the physical interface assignment to a VLAN is considered device-specific configuration. Each BIG-IP device has its own unique set of physical interfaces, and therefore, the mapping of a VLAN to a specific physical interface must be configured locally on each cluster member.

Resetting the Device Trust of the BIG-IP Cluster is an drastic action that would break HA communication and is not a solution for synchronizing device-specific VLAN interface assignments.

Configuring a default route for the new VLAN is a Layer 3 routing configuration task and does not address the Layer 2 issue of the VLAN's presence or interface assignment on Cluster Member B.

Enabling the interface on Cluster Member A ensures it is active on that device, but it does not synchronize the physical VLAN-to-interface mapping to Cluster Member B, which has its own independent physical interfaces.