Originally, max. payload was defined as 1500 bytes in 802.3. Ethernet v2 supports frame length of >=1536 and this is what IP implementations use. Most carrier-class vendors support around 9000 bytes ("jumbo frames") these days. Since 1500 byte is the standard that all Ethernet implementations must support, this is what is normally set as default on all interfaces.
|2 of 2||changed to better reflect the IEEE standards|