Ethernet II vs IEEE 802.3: Key Differences Explained
If you have ever looked at an Ethernet frame in Wireshark and wondered why the 2-byte field at offset 12 is sometimes labelled “EtherType” and sometimes “Length”, this post explains the reason. 1. Ethernet II (also called DIX Ethernet) Origin: Defined jointly by DEC, Intel, and Xerox in 1980 — hence the alternative name “DIX Ethernet”. Frame structure: Field Size Meaning Destination MAC 6 B Target station address Source MAC 6 B Sending station address EtherType 2 B Upper-layer protocol identifier Payload 46–1500 B Network-layer packet FCS (CRC-32) 4 B Frame check sequence The 2-byte field carries an EtherType value — a number that directly identifies which protocol is encapsulated in the payload: ...