13-41
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 13 Configuring Interface Characteristics Configuring the System MTU
The upper limit of the system routing MTU value is based on the switch or switch stack configuration
and refers to either the currently applied system MTU or the system jumbo MTU value. For more
information about setting the MTU sizes, see the system mtu global configuration command in the
command reference for this release.
Beginning in privileged EXEC mode, follow these steps to change the MTU size for switched and routed
packets:
Catalyst 3750-only stack
Catalyst 3750 switch
Catalyst 3560 switch
Use the system mtu bytes
command.
The range is from 1500 to 1998
bytes.
Use the system mtu jumbo
bytes command.
The range is from 1500 to 9000
bytes.
Use the system mtu routing
bytes command.
The range is from 1500 to the
system MTU value (in bytes).
1. If you use the system mtu bytes command on a Catalyst 3750-X or 3750-E member in a mixed hardware stack, the setting takes effect on the Fast Ethernet
ports of Catalyst 3750 members.
2. The system routing MTU value is the applied value, not the configured value.
Table 13-5 System MTU Values (continued)
Configuration system mtu command system jumbo mtu command system routing mtu command
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 system mtu jumbo bytes (Optional) Change the MTU size for all Gigabit
Ethernet and 10-Gigabit Ethernet interfaces on the
switch or the switch stack. For information about the
range for bytes, see Table 13-5.
Step 3 system mtu routing bytes (Optional) Change the system MTU for routed ports.
You can also set the maximum MTU to be advertised by
the routing protocols that support the configured MTU
size. 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.
For information about the range for bytes, see
Table 13-5.
Note This command is not supported on switches
running the LAN base feature set.
Step 4 system mtu bytes (Optional) In a mixed hardware stack, change the MTU
size for all Fast Ethernet interfaces on the Catalyst 3750
members.
The range is 1500 to 1998 bytes; the default is
1500 bytes.
Note This command does not apply to
Catalyst 3560-X switches.
Step 5 end Return to privileged EXEC mode.
Step 6 copy running-config startup-config Save your entries in the configuration file.
Step 7 reload Reload the operating system.
Step 8 show system mtu Verify your settings.