Changing the IPv6 MTU
IPv6 MTU changes are performed on individual interfaces.
The following example configures the MTU of an IPv6 packet to be 1280 bytes for Ethernet interface 1/3/1.
device# configure terminal device(config)# interface ethernet 1/3/1 device(config-if-e1000-1/3/1)# ipv6 mtu 1280
Note: IPv6 MTU cannot be configured globally. It is supported only on devices running Layer
3 software.