This configuration allows separate links between the firewall and switches to carry management traffic and data traffic. With a common link, the management traffic and data traffic run in the same uplink. If data traffic is congested, so is management traffic, which results in a delay in forwarding management traffic. If data traffic is congested, consider configuring separate links for management traffic and data traffic. Although similar to a common link configuration, the isolated management/data configuration runs separate uplinks for management traffic and data traffic. This configuration ensures that even with a high amount of data traffic, management traffic to the switch is forwarded without being delayed.
NOTE: The MGMT port cannot be portshielded.
Isolated Link Topology shows an isolated link setup of a firewall with a switch:

Isolated links for management and data traffic:


TIP: You can have VLAN sub-interfaces configured under X3 and configure other ports on the switch as part of those VLANs too. Since, X3 is unassigned, portshielding to X3 itself without any VLANs will give you the following error: 'Common uplink does not have VLAN(s) configured. Please select another Portshield interface'