Hi,
That is the only command you need. Verify with show command:
see below:
This example shows how to configure the MTU size on Gigabit Ethernet port 1/1:
switch(config)# interface gi1/1
switch(config-if)# mtu 9198
switch# show interface gigabitethernet 1/2
GigabitEthernet1/2 is administratively down, line protocol is down
Hardware is C6k 1000Mb 802.3, address is 0030.9629.9f88 (bia 0030.9629.9f88)
MTU 9216 bytes, BW 1000000 Kbit, DLY 10 usec,
HTH