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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
OL-12247-04
Chapter 11 Configuring Interface Characteristics
Configuring the System MTU
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.
•
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.
•
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.
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.
Command
Purpose