* Paul de Weerd <weerd@weirdnet.nl> [2008-08-21 13:48]:
quoted text
> On Thu, Aug 21, 2008 at 09:50:35AM +0000, Stuart Henderson wrote:
> | > you can stack vlans. aka
> | >
> | > ifconfig vlan2 vlan 2 vlandev em0
> | > ifconfig vlan4 vlan 4 vlandev vlan2
> | >
> | 
> | I think you have to take a hit on MTU, so this is probably better
> | on gigabit interfaces that are configured for jumbo frames (using
> | ifconfig to increase MTU configures them for jumbos).
> | 
> | Cisco does something similar (qinq) but iirc they use a different
> | ethertype, so it may not be directly compatible.
> 
> The standard specifies 0x88a8 for 'qinq' or 'stacked vlans' or
> 802.1ad (Provider Bridges). OpenBSD uses 0x8100 for both the outer and
> the inner ethertype (which may give interoperability issues with other
> vendors, don't know, don't have gear that supports it).
> 
> Attached is a patch that adds ETHERTYPE_8021AD to ethertypes.h.

no point in just doing that.

a button to change the ether type would make sense.

-- 
Henning Brauer, hb@bsws.de, henning@openbsd.org
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