How to set Fortigate interface to special speed

FG60R1-135-23~$ sh sys int

config system interface

    edit "internal"

        set ip 192.168.135.233 255.255.255.0

        set allowaccess ping https ssh snmp

    next

    edit "wan1"

        set ip 216.93.188.206 255.255.255.240

        set allowaccess ping https ssh snmp

        set speed 10full

 

 

FG60R1-135-23~$ conf sys int

 

(interface)$ edit dmz

 

(dmz)$ set speed

 100full    100M full-duplex

 100half    100M half-duplex

 10full     10M full-duplex

 10half     10M half-duplex

 auto       auto adjust speed

 

(dmz)$ set speed 100full

(dmz)$ end