Ethereal-users: Re: [Ethereal-users] Regarding 802.1q

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From: Marco van den Bovenkamp <marco@xxxxxxxxxxxxxxxxxxx>
Date: Wed, 09 Mar 2005 19:08:39 +0100
Scott Lowrey wrote:
Some hubs/switches will drop VLAN-tagged frames because they don't understand the tag (which appears as a bogus type field to a non-VLAN-aware device).
Shouldn't happen for any frame that's not longer than 1518 bytes including VLAN tag. Why should a switch care about what the frame looks like, besides size, source & destination MAC adresses and CRC? The only frames such a switch should drop are those that have more than 1496 payload bytes, as they end up as well-formed frames longer than 1518 bytes ('baby giants').
I have, however, seen small NetGear gigabit switches that will pass tagged packets even though they are not VLAN-aware.
And so they should, with the proviso that they are otherwise OK (not longer than 1518 bytes). 

--

		Regards,

			Marco.