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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 13 Configuring Interface Characteristics Configuring the System MTU

Configuring SVI Autostate Exclude

Configuring SVI autostate exclude on an access or trunk port in an SVI excludes that port in the
calculation of the status of the SVI line state (up or down) status even if it belongs to the same VLAN.
When the excluded port is in the up state, and all other ports in the VLAN are in the down state, the SVI
state is changed to down.
At least one port in the VLAN should be up and not excluded to keep the SVI state up. You can use this
command to exclude the monitoring port status when determining the status of the SVI.
Beginning in privileged EXEC mode, follow these steps to exclude a port from SVI state-change
calculations:
This example shows how to configure an access or trunk port in an SVI to be excluded from the line-state
status calculation:
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface gigabitethernet1/0/2
Switch(config-if)# switchport autostate exclude
Switch(config-if)# exit
Configuring the System MTU
The default maximum transmission unit (MTU) size for frames received and sent on all interfaces on the
switch or switch stack is 1500 bytes. You can change the MTU size to support switched jumbo frames
on all Gigabit Ethernet and 10-Gigabit Ethernet interfaces and to support routed frames on all routed
ports.
• The system jumbo MTU value applies to switched packets on the Gigabit Ethernet and 10-Gigabit
Ethernet ports of the switch or switch stack. Use the system mtu jumbo bytes global configuration
command to specify the system jumbo MTU value.
• The system routing MTU value applies only to routed packets on all routed ports of the switch or
switch stack. Use the system mtu routing bytes global configuration command to specify the
system routing MTU value.
When configuring the system MTU values, follow these guidelines:
• The switch does not support the MTU on a per-interface basis.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 interface interface-id Specify a Layer 2 interface (physical port or port
channel), and enter interface configuration mode.
Step 3 switchport autostate exclude Exclude the access or trunk port when defining the
status of an SVI line state (up or down)
Step 4 end Return to privileged EXEC mode.
Step 5 show running config interface interface-id
show interface interface-id switchport
(Optional) Show the running configuration.
Verify the configuration.
Step 6 copy running-config startup-config (Optional) Save your entries in the configuration file.