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    <title>Path MTU Discovery for IPv6 </title>
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<a name="wp1089167"> </a><h1 class="pTitle">
Path MTU Discovery for IPv6

</h1>
<a name="wp1073095"> </a><p class="pBody">
As in IPv4, path MTU discovery in IPv6 allows a host to dynamically discover and adjust to differences 
in the MTU size of every link along a given data path. In IPv6, however, fragmentation is handled by the 
source of a packet when the path MTU of one link along a given data path is not large enough to 
accommodate the size of the packets. Having IPv6 hosts handle packet fragmentation saves IPv6 router 
processing resources and helps IPv6 networks run more efficiently.

</p>
<a name="wp1073096"> </a><p class="pBodyAutonumNoRule">
<strong>Note	&nbsp;&nbsp;&nbsp;</strong> In IPv4, the minimum link MTU is 68 octets, which means that the MTU size of every link along a given 
data path must support an MTU size of at least 68&#160;octets.<br />
<br />
In IPv6, the minimum link MTU is 1280 octets. We recommend using MTU value of 1500 octets for 
IPv6 links.

</p>
<hr /><br><p class="pBody">Copyright 2010-2013, Cisco Systems, Inc. All rights reserved.</p> 

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