CLI Reference Guide

412 Ethernet Configuration Commands
Example
a11-39#show system mtu
System Jumbo MTU size is 9216 bytes
system jumbo mtu
Use the system jumbo mtu command to globally configure the Maximum
Transmission Unit (MTU) on all interfaces, IP/IPv6 interfaces, VLAN
interfaces, and port channel interfaces for forwarded and system-generated
frames. The MTU is the size of the largest Ethernet frame that can be
transmitted on an interface without fragmentation. Frames received on an
interface are dropped if they exceed the MTU. Frames larger than this size
generated by the system are fragmented.
This command deprecates the mtu, ip mtu, and ipv6 mtu commands.
Use the no form of the command to reset the MTU to the default.
Syntax
system jumbo mtu frame size
no system jumbo mtu
• frame size —The maximum frame size, in bytes, received by the system
which is not forwarded.
Default Configuration
The default MTU size is 1518 bytes (1522 bytes for VLAN tagged frames).
Command Modes
Global Configuration mode
User Guidelines
The IP and IPv6 MTU are set to the MTU minus 18 bytes. IP packets
forwarded in software are dropped if they exceed the IP MTU. Packets
originated on the router, such as OSPF packets, may be fragmented by the IP
stack. OSPF advertises the IP MTU in the Database Description packets it
sends to its neighbors during database exchange. If two OSPF neighbors
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