Is Ethernet is exactly the same as 802.3?

Answer 1

No.

Ethernet and token ring have now become standards. However, the access

method and the standard are not always the same. Ethernet is based on IEEE

802.3 standards, but is not exactly the same as IEEE 802.3. Some vendors'

IEEE 802.3 equipment will not work with ethernet. Token ring and 802.5 are the

same, despite token ring's origins as an IBM proprietary standard. Non-IBM

vendors can provide 802.5 equipment that will work with IBM token rings,

provided the equipment follows 802.5 standards