Why is there a limit to the minimum and maximum frame length?

The traditional Ethernet is a * * * shared LAN, which adopts CSMA/CD protocol of carrier sense multiple access/collision detection. The minimum frame length must be greater than the maximum delay bit of the whole network (data bits that can be transmitted within the maximum delay time).

If the frame length is too small, two frames may spread on the network at the same time, resulting in a collision (collision), which makes the network unable to send data.

If the data frame is too long, some jobs can't send data for a long time, which may exceed the buffer size at the receiving end, resulting in buffer gain.

Due to various restrictions, the minimum size of each Ethernet frame is 64 bytes, and the maximum size is 65,438+0,565,438+0.8 bytes. For Ethernet frames less than or greater than this limit, we can regard them as error data frames, and general Ethernet forwarding equipment will discard these data frames.

(Note: Data frames smaller than 64 bytes are generally caused by "fragmentation" caused by Ethernet collision or line interference or poor Ethernet interface. For data frames larger than 15 18 bytes, we generally call them jumbo frames, which are usually caused by line interference or poor Ethernet interface. )