Configuring The System Mtu - Cisco 3032 Software Configuration Manual

Configuring the System MTU

Command
Step 5
show running config interface interface-id
show interface interface-id switchport
Step 6 copy running-config startup-config
This example shows how to configure an access or trunk port in an SVI to be excluded from the 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.
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When configuring the system MTU values, follow these guidelines:
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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
11-26
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.
The switch does not support the MTU on a per-interface basis.
You can enter the system mtu bytes global configuration command on a switch, but the command
does not take effect on the switch.
The system mtu jumbo global configuration commands do not take effect when you enter the
system mtu routing command on a switch on which only Layer 2 ports are configured.
When you use the system mtu bytes or system mtu jumbo bytes command to change the system
MTU or system jumbo MTU size, you must reset the switch before the new configuration takes
effect. The system mtu routing command does not require a switch reset to take effect.
The system MTU jumbo setting is saved in the switch environmental variable in NVRAM and
becomes effective when the switch reloads. Unlike the system MTU routing configuration, the MTU
settings you enter with the system mtu and system mtu jumbo commands are not saved in the
switch Cisco IOS configuration file, even if you enter the copy running-config startup-config
privileged EXEC command. Therefore, if you use TFTP to configure a new switch by using a backup
configuration file and want the system MTU to be other than the default, you must explicitly
configure the system mtu and system mtu jumbo settings on the new switch and then reload the
switch.
Chapter 11 Configuring Interface Characteristics
Purpose
(Optional) Show the running configuration.
Verify the configuration.
(Optional) Save your entries in the configuration file.
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