Re: VLAn support for atheros/Prism?

From: Ruslan Ermilov <ru_at_freebsd.org>
Date: Fri, 6 Feb 2004 03:56:55 +0200
On Thu, Feb 05, 2004 at 04:49:26PM -0800, Brooks Davis wrote:
> On Thu, Feb 05, 2004 at 04:31:12PM -0800, mrcpu_at_cdsnet.net wrote:
> > Well, I'm just looking through the specs of the microtik stuff, and they
> > say they have vlan support over wireless now.
> > 
> > I can fudge the VLAn support, at the cost of a reduced MTU using the
> > "software emulation" vlan tagging, or whatever it is that FreeBSD does,
> > and bridge those packets, but that's not the same as true hardware VLAN
> > tagging.
> 
> You've got a serious misconception about how vlans work.  The only
> hardware support that is required is support for a wire MTU of 1504
> bytes so the tag fits on the packet without reducing payload size.  Some
> interfaces have support for removing the tag from the packet for you and
> indicating the tag out of band, but that's only an optimization.
> 
I think the originator is asking why IFCAP_VLAN_MTU is not set by
the ath(4) driver (I've only checked with grep(1)), is it due to
a hardware limitation, or due to the driver?


Cheers,
-- 
Ruslan Ermilov
FreeBSD committer
ru_at_FreeBSD.org

Received on Thu Feb 05 2004 - 16:57:02 UTC

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