The ethernet IEEE 802.3 standard defines the minimum Ethernet frame size as 64 bytes, and the maximum frame size as 1518 bytes. Why is There a Minimum and Maximum Ethernet Frame size?

For example:

An ethernet frame has a minimum size because anything that is shorter than the 64 byte minimum is interpreted by receiving stations as a collision and is automatically discarded.

But why maximum as 1518?


Different frame sizes accommodate different traffic needs. For instance, VoIP traffic is best served by many small datagrams, and a server backup is better served by fewer but larger datagrams.

If you had one fixed frame size, you could end up wasting a lot of network bandwidth by padding for VoIP with larger frame sizes, or you could end up wasting a lot of bandwidth with protocol overhead for server backups with smaller frame sizes.

One size does not fit all.

Edit to answer your changed question:

The sizes go back to the original ethernet medium. The minimum of 64 bytes was the minimum to make sure that a frame completely filled the medium from end-to-end so that the other hosts could detect that the medium is in use. The minimum is too small for some applications, so a maximum needed to be determined..

Your question of why the choice for the maximum size is actually answered in another question: How was the MTU size for ethernet frames calculated as 1500 bytes?

  • Sorry that is not what I am looking for. I'll re-frame the question.
    – j29392
    Nov 8 '15 at 23:58

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