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The default maximum transmission unit (MTU) size for frames received and sent on all switch interfaces 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.
When configuring the system MTU values, follow these guidelines:
Beginning in privileged EXEC mode, follow these steps to change the MTU size for switched and routed packets:
1.
configure terminal
2.
system mtu
bytes
3.
system mtu
jumbo
bytes
4.
system mtu routing
bytes
5.
end
6.
copy
running-config startup-config
7.
reload
8.
show system mtu
This example shows how to set the maximum packet size for a Gigabit Ethernet port to 7500 bytes:
Switch(config)# system mtu 1900 Switch(config)# system mtu jumbo 7500 Switch(config)# exit
If you enter a value that is outside the allowed range for the specific type of interface, the value is not accepted. This example shows the response when you try to set Gigabit Ethernet interfaces to an out-of-range number:
Switch(config)# system mtu jumbo 25000
^
% Invalid input detected at '^' marker.
This is an example of output from the show system mtu command:
Switch# show system mtu
Global Ethernet MTU is 1500 bytes.
Description | Link |
---|---|
To help you research and resolve system error messages in this release, use the Error Message Decoder tool. |
https://www.cisco.com/cgi-bin/Support/Errordecoder/index.cgi |
MIB | MIBs Link |
---|---|
All supported MIBs for this release. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
Description | Link |
---|---|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |
Release |
Modification |
---|---|
Cisco IOS 15.0(2)EX1
|
This feature was introduced. |