Date: Wed, 29 Aug 2007 14:25:49 +0100 From: "Bruce M. Simpson" <bms@FreeBSD.org> To: Ivan Alexandrovich <ivsan@ngs.ru> Cc: freebsd-net@freebsd.org Subject: Re: vlan stacking Message-ID: <46D573DD.3080709@FreeBSD.org> In-Reply-To: <46D54CC8.4020702@ngs.ru> References: <46D54CC8.4020702@ngs.ru>
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Ivan Alexandrovich wrote:
> Hi
>
> I'm wondering is anybody using double vlans ("q-in-q",
> "vlan stacking", any name you like) on production hosts?
> Does it play well with common ethernet device drivers in freebsd
> (concerning the frame size) - fxp, em, for example?
>
> Looks like that almost nobody mentions q-in-q in freebsd
> maillists/forums,
> except that nesting ng_vlan can be used to implement it.
I'm sure you or someone else can come up with a creative solution for
Q-in-Q or arbitrary nesting levels. It's not something I use, so, I pass.
The mainline code doesn't support it without Netgraph; it would be
necessary to allow vlan(4) to be nested. The ether_input() code demuxes
802.1q encapsulation but only 1 level. The reason for this is because
the outer VLAN tag got moved into the mbuf pkthdr structure for
if_bridge to be able to process it.
I can't comment on the netgraph solution however.
regards
BMS
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