IP MTU
IP Maximum Transmission Unit (MTU)
IPv4 requires that every node must be able to
forward an IP packet of 68 bytes without any further fragmentation. This
is because an IPv4 header can be as large as 60 bytes in length or have
a minimum fragment size of 8 bytes. Every IPv4 node that is the final
destination of the IPv4 packet must be able to receive an IPv4 packet of
a minimum size of 576 bytes, which can be all or fragments of the
original packet.
IPv6 requires that every link have a minimum
MTU of 1280 bytes, with a recommended MTU of 1500 bytes, compared to 68
bytes in IPv4. It is recommended that IPv6 devices perform Path Discovery MTU to avoid fragmentation.
