EXFO ETS-1000G - Manual (Page 181)

10 Gigabit Ethernet Analyzer 171
D Ethernet Frame Structure
Destination MAC Address — A destination MAC address. A 6-byte field that
contains an IP address of the network node to which the frame is
addressed.
Source MAC Address — A source MAC address. A 6-byte field that contains
an address of the frame sender.
Length/Type — Length/Type. This field contains a 16-bit integer and can
take on one of two values:

If the number specified in this field is less than or equal to 1500, then
the field will take on the Length value and it will define a data field's
length.

If the number specified in this field is greater than or equal to 1536,
then the field will take on the Type value and it will indicate the type of
the protocol being used.
Data — A data field that may contain from 46 or 42 (if the frame contains a
VLAN tag) to 1500 bytes.
Pad — A padding field. If a data field's length is less than 46 bytes, then the
frame will be padded with a padding field to the minimum possible value
(64 bytes).