Configuring the Media MTU
The media maximum transmission unit (MTU) is the largest data unit that can be forwarded without fragmentation. The default media MTU size used on a physical interface depends on the encapsulation being used on that interface. For a listing of MTU sizes for each encapsulation type, see Media MTU Sizes by Interface Type.
To configure the media-MTU size:
- In configuration mode, go to the [edit interfaces interface-name] hierarchy level.[edit ]user@host# [edit interfaces interface-name]
- Include the mtu statement.[edit interfaces interface-name]mtu bytes;
If you change the size of the media MTU, you must ensure that the size is equal to or greater than the sum of the protocol MTU and the encapsulation overhead. You configure the protocol MTU by including the mtu statement at the following hierarchy levels:
[edit interfaces interface-name unit logical-unit-number family family inet]
[edit interfaces interface-name unit logical-unit-number family family inet6]
[edit logical-systems logical-system-name interfaces interface-name unit logical-unit-number family family]
Changing the media MTU or protocol MTU causes an interface to be deleted and added again.
If you configure an MTU value by including the mtu statement at the [edit interfaces interface-name unit logical-unit-number family mpls] hierarchy level, the configured value is used.