Enabling or Disabling the Path MTU Discovery Protocol show mtu
2-90 Startup and General Configuration

Enabling or Disabling the Path MTU Discovery Protocol

Purpose
ToenableordisablethepathMTU(MaximumTransmissionUnit)discoveryprotocolonthe
device.Becauseportswithtransmissionspeedshigherthan100Mbpsarecapableoftransmitting
framesuptoamaximumof10,239bytes,itisnecessarytohavethepathMTUdiscoveryprotocol
enabledifjumboframes���areallowedinthenetwork.Ifthesystemreceivesaframelargerthanthe
destinationportsupports,itwillsendan“ICMPdestinationunreachable”errormessage
indicatingtothetransmittingstationthatitmustfragmenttheframe.
Commands

show mtu

UsethiscommandtodisplaythestatusofthepathMTUdiscoveryprotocolonthedevice.
Syntax
show mtu
Parameters
None.
Defaults
None.
Mode
Switchcommand,ReadOnly.
Example
ThisexampleshowshowtodisplaypathMTUdiscoverystatus:
Matrix(rw)->show mtu
MTU discovery status: Enabled
Note: By default, path MTU discovery is enabled on the device and jumbo frame support is disabled
on all ports. When jumbo frame support is enabled with the set port jumbo command, as described
in “set port jumbo” on page 4-28, path MTU discovery should not be disabled.
For information about... Refer to page...
show mtu 2-90
set mtu 2-91
clear mtu 2-91