Users Guide

Table Of Contents
Layer 2 Switching Commands 454
system jumbo mtu
Use the system jumbo mtu command to globally configure the link
Maximum Transmission Unit (MTU) on all interfaces, IP/IPv6 interfaces,
VLAN interfaces, and port channel interfaces for forwarded and system-
generated frames. The link 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 link MTU. Frames larger than
this size generated by the system are fragmented before transmission.
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
Dell EMC Networking N-Series switches do not fragment received packets.
The IPv4 and IPv6 MTU are set to the link 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
advertise different IP MTUs, they will not form an adjacency (unless OSPF
has been instructed to ignore differences in IP MTU with the ip ospf
mtuignore command).