On Oct 16, 2008, at 10:08 AM, Joerg Mayer wrote:
What is the minimum frame size of a tagged Ethernet frame (802.1Q)?
64 or 68?
64. See section 3.5 of
http://standards.ieee.org/getieee802/download/802.3-2005_section1.pdf
(I obviously left out the preamble and SFD, but included the FCS).
I think the minimum frame size originally came from a requirement that
an Ethernet frame had to span the entire Ethernet segment by the time
the last part of the frame was transmitted; that means that the total
content of the frame, including the Ethernet header, any 802.1Q
headers, the payload, and the FCS, has to be >= the minimum size, so
the more 802.1Q headers you have, the fewer bytes of payload you need
to get to the minimum frame size.
