<P> In the context of Internet Protocol, MTU refers to the maximum size of an IP packet that can be transmitted without fragmentation over a given medium . The size of an IP packet includes IP headers but excludes headers from lower levels in the protocol stack . </P> <P> The MTU should not be confused with the minimum datagram size that all hosts must be prepared to accept, which has a value of 576 bytes for IPv4 and of 1280 bytes for IPv6 . It should also not be confused with the maximum size for the physically transmitted frame . In the case of an Ethernet frame this adds an overhead of 18 bytes, or 22 bytes with an IEEE 802.1 Q tag for VLAN or quality of service . </P> <Table> <Tr> <Th> Media for IP transport </Th> <Th> Maximum transmission unit (bytes) </Th> <Th> Notes </Th> </Tr> <Tr> <Td> Internet IPv4 path MTU </Td> <Td> At least 68, max of 64 KiB </Td> <Td> Practical path MTUs are generally higher . Systems may use Path MTU Discovery to find the actual path MTU . Routing from larger MTU to smaller MTU causes IP fragmentation . </Td> </Tr> <Tr> <Td> Internet IPv6 path MTU </Td> <Td> At least 1280, max of 64 KiB, but up to 4 GiB with optional jumbogram </Td> <Td> Practical path MTUs are generally higher . Systems must use Path MTU Discovery to find the actual path MTU . </Td> </Tr> <Tr> <Td> Ethernet v2 </Td> <Td> 1500 </Td> <Td> Nearly all IP over Ethernet implementations use the Ethernet V2 frame format . </Td> </Tr> <Tr> <Td> Ethernet with LLC and SNAP </Td> <Td> 1492 </Td> <Td> </Td> </Tr> <Tr> <Td> Ethernet jumbo frames </Td> <Td> 1501--9198 or more </Td> <Td> The limit varies by vendor . For correct interoperation, the whole Ethernet network (segment) must support the same maximum frame size . Jumbo frames are usually only seen in special - purpose networks . </Td> </Tr> <Tr> <Td> PPPoE v2 </Td> <Td> 1492 </Td> <Td> Ethernet v2 MTU (1500) less PPPoE header (8) </Td> </Tr> <Tr> <Td> DS - Lite over PPPoE </Td> <Td> 1452 </Td> <Td> Ethernet v2 MTU (1500) less PPPoE header (8) and IPv6 header (40) </Td> </Tr> <Tr> <Td> PPPoE jumbo frames </Td> <Td> 1493--9190 or more </Td> <Td> Ethernet Jumbo Frame MTU (1501 - 9198) less PPPoE header (8) </Td> </Tr> <Tr> <Td> WLAN (802.11) </Td> <Td> 2304 </Td> <Td> The maximum MSDU size is 2304 before encryption . WEP will add 8 bytes, WPA - TKIP 20 bytes, and WPA2 - CCMP 16 bytes . </Td> </Tr> <Tr> <Td> Token Ring (802.5) </Td> <Td> 4464 </Td> <Td> </Td> </Tr> <Tr> <Td> FDDI </Td> <Td> 4352 </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> Media for IP transport </Th> <Th> Maximum transmission unit (bytes) </Th> <Th> Notes </Th> </Tr>

What is the maximum size of an ip packet for ipv4 or ipv6