DHCP client options on Cisco IOS
If you want to test DHCP using Cisco IOS devices then you have multiple options for DHCP clients.
Switches
SVI Interface
You can use an Switching - switched virtual interface (SVI).
SW1(config)#interface vlan 120 SW1(config-if)#ip address dhcp
Routed Interface
Another option is a Switch configuring a routed port.
SW1(config)#interface GigabitEthernet 1/0/21 SW1(config-if)#no switchport SW1(config-if)#ip address dhcp
Router
Sub-interface
R1(config)#interface GigabitEthernet 0/1.10 R1(config-subif)#encapsulation dot1Q 10 R1(config-subif)#ip address dhcp