What is JUMBO frame?

That's because jumbo frames are not standard.

However, if you use the "type" format, there's no reason in principle why the frame size can't grow beyond 1522 bytes. Of course, all switches in the path must be aware of the possibility of these jumbo frames.

Bert

Jumbo frames are Ethernet frames with more than 1,500 bytes of payload. Conventionally, jumbo frames can carry up to 9,000 bytes of payload. Why 9000? because ethernet uses a 32 bit CRC that loses its effectiveness above about 12000 bytes. Many Gigabit Ethernet switches and Gigabit Ethernet network interface cards support jumbo frames. You can partition a logical network in which systems can exchange Jumbo Frames and mark them with IEEE 802.1Q virtual LAN tags. The extended frames will be transparent to the rest of the network. Adapters that implement IEEE 802.1Q can support different Ethernet frame sizes for different logical network interfaces. For example, a server could communicate with another server using Jumbo Frames while communicating with clients sitting on another VLAN or IP subnet using standard Ethernet frames - all via the same physical connection.

pranav tailor

There is no "de jure" standard for the size of a "jumbo frame" as the IEEE has not seen fit to create one. One can argue though that the "de facto" standard for the jumbo frame is such that it results in an IPv4 MTU of 9000 bytes or more based on that being what Alteon used in their GbE NICs which IIRC were among if not the first to have a "jumbo frame" in the Ethernet space.

rick jones

(At least they were the first place I can recall seeing jumbo frames in an Ethernet interface)

Agreed, although i have seen "jumbo" on 100 Mbps as well, although cannot remember where, and it has spread to 10G as well.

A Cisco Cat 6500 could even have more than 1 different jumbo limits, just on different blades if you had various vintages of equipment.

and the telecomms suppliers do not agree about 9000 bytes: - some Marconi SDH kit calls 4000+ bytes "jumbo". - and DWDM kit often works happily at 64 Kbytes since they dont even worry about packet boundaries.

and then there is "baby jumbo" which is more than standard 1514 /