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What is the actual reason for limiting the Ethernet payload to 1500 bytes?
The size is governed based on the physical properties of the communications media. Historical network media were slower and more prone to errors so the MTU sizes were set smaller. For most Ethernet networks this is set to 1500 bytes and this size is used almost universally on access networks.
What happens if a Ethernet packet has a payload less than 46 bytes?
If the network layer wishes to send less than 46 bytes of data the MAC protocol adds sufficient number of zero bytes (0x00, is also known as null padding characters) to satisfy the requirement. Some buggy drivers fail to do this though as noted by Adaptec.
Why does Ethernet put a constraint on the minimum frame length of data payload?
Since data travels at a finite speed a minimum packet size was required to ensure that if a collision happens it happened everywhere. The larger you make the minimum packet size the larger and/or faster you can make the network before CSMA/CD breaks down.
What is the minimum payload size for Ethernet?
After subtracting 18 bytes for the ethernet header and CRC, you get 46 bytes of Ethernet payload as the minimum payload size. Slot time (and thus the minimum frame size) is also closely related to Ethernet collision detection.
How many bytes are in an Ethernet frame?
As you know, ethernet frame has 8 byte preamble, 6 byte source and 6 byte destination mac address, mac type of 2 bytes, and 4 bytes CRC. Assuming the MTU payload to be 1500 the total number of bytes comes to 1500 + 8 + 6 + 6 + 2 + 4 = 1526 bytes.
Why is the MTU size of 1500 bytes?
Assuming the MTU payload to be 1500 the total number of bytes comes to 1500 + 8 + 6 + 6 + 2 + 4 = 1526 bytes. Now between each frame there is a inter frame gap of 12 bytes which constitues 9.6micro seconds gap between each frame. This is essential so that frames dont mix up.
What is the frame rate of 10 Mbps?
So at 10 Mbps rate, the frame rate is 10 Mbps / 1538 bytes = 812.74 frames / second. Now we can find the throughput or efficiency of link, to transmit 1500 bytes of payload. by multiplying the frame rate with the number of bytes of the payload.