Dell Networking 7048, Reference Manual

Page: 1011 / 1788

IP Routing Commands
1011
ip mtu
Use the ip mtu command in Interface Configuration mode to set the IP
Maximum Transmission Unit (MTU) on a routing interface. The IP MTU is
the size of the largest IP packet that can be transmitted on the interface
without fragmentation. Packets forwarded in hardware ignore the IP MTU.
Packets forwarded in software are dropped if they exceed the IP MTU of the
outgoing interface.
Packets originated on the router, such as OSPF packets, may be fragmented
by the IP stack. The IP stack uses its default IP MTU and ignores the value set
using the
ip mtu
command. 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).
Syntax
ip mtu [
bytes
]
no ip mtu
Parameter Description
Default Configuration
1500 bytes is the default configuration.
Command Mode
Interface Configuration (VLAN) mode, Global Configuration mode
User Guidelines
Using this command in Global Configuration mode sets the IP MTU for all
routing VLANs. This setting is adjusted internally when the link MTU
command is issued.
Parameter Description
bytes
Specifies the maximum transmission size of an IP frame.
(Range: 68-9198)
2CSPC4.X7000-SWUM204.book Page 1011 Friday, March 15, 2013 8:22 AM