Technical Tip: Data interfaces on all VMX security nodes are set with speed and duplex 10full

Sometimes speed and duplex settings of the data interfaces on the VMX nodes can lead to misunderstanding.

For example:

FortiGate-VMX (global) # diagnose hardware deviceinfo nic internal
Name: internal
Driver: tun
Version: 1.6
FW version: N/A
Bus: tap
Hwaddr: 02:69:65:d1:60:52
State: up
Link: up
Mtu: 65521
Supported:
Advertised:
Speed: 10full

It is expected behavior. 

Data interfaces are virtual interfaces, therefore the speed/duplex definition of a regular physical interface is not applicable to the virtual interface.

The actual speed of the virtual data interfaces depends on the physical layer of the hypervisor.