System Mtu - Cisco Catalyst 3750 Metro Command Reference Manual

system mtu

system mtu
Use the system mtu global configuration command to set the maximum packet size or maximum
transmission unit (MTU) size for Gigabit Ethernet ports or for Fast Ethernet (10/100) ports or to set an
alternate MTU for specific ports. Use the no form of this command to restore the global MTU value to
its default value.
Syntax Description bytes
alternate bytes
alternate
interface
{interface-id |
range
interface-range}
jumbo bytes
routing bytes
Defaults The default MTU size for all ports is 1500 bytes. However, if you configure a different value for the
system MTU, that configured value becomes the default MTU size for routed ports when it is applied
following a switch reset.
Command Modes
Global configuration
Command History Release
12.1(14)AX
12.2(25)SED
12.2(55)SE
Catalyst 3750 Metro Switch Command Reference
2-734
system mtu {bytes | alternate {bytes | interface interface-id} | jumbo bytes | routing bytes}
no system mtu
Set the system MTU for ports that are set to 10 or 100 Mb/s. The range is 1500 to
1998 bytes. The default is 1500 bytes. This is the maximum MTU received at
10/100-Mb/s Ethernet switch ports.
Define an alternate frame size (MTU) to be applied to specific interfaces. The range
is between the configured system MTU and the configured jumbo MTU size (1500
to 9000 bytes). The default is 1500 bytes.
Apply the alternate MTU to the specified interface or range of interfaces.
Set the system jumbo frame size (MTU) for Gigabit Ethernet ports. The range is
1500 to 9000 bytes. The default is 1500 bytes. This is the maximum MTU received
at the physical port for Gigabit Ethernet ports.
Set the maximum MTU for routed packets. You can also set the maximum MTU to
be advertised by the routing protocols that support the configured MTU size. The
range is 1500 bytes to the system MTU value. The system routing MTU is the
maximum MTU for routed packets and is also the maximum MTU that the switch
advertises in routing updates for protocols such as OSPF.
Although larger packets can be accepted, they cannot be routed.
Modification
This command was introduced.
The bytes range is now 1500 to 1998. The routing bytes keywords were
added.
The alternate {bytes | interface interface-id} keywords were introduced.
Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands
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