Ethernet II vs 802.3 Frames

• Telling them Apart

  • NIC must recognize incoming frame’s type
  • If 2 bytes after SA <= 1500, must be 802.3 because of maximum length limitation in 802.3
  • If 2 bytes after SA 򗮼, it’s an Ethertype

Preamble

SFD

DA

SA

Ethertype

Preamble

SFD

DA

SA

Length

LLC Frame

FCS

Data

FCS

Ethernet II Frame

802.3 Frame

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