Re: Double stacked VLANs (was Re: Question on header check)

Peter Stuge wrote:
> On Tue, Jun 20, 2006 at 07:21:18AM -0700, Ben Greear wrote:
> 
>>>>packet on socket on eth0 = no tag on packet on wire
>>>>packet on socket on eth0.1 = VLAN1 tag on packet on wire
>>>>packet on socket on eth0.1.2 = VLAN2 tag on VLAN1 tag on packet on wire
>>>>
>>>
>>>I agree.  If the program which owns the raw socket *really* wants
>>>to send a non-vlan frame then it would probably use eth0!
>>
>>We currently will encapsulate a raw pkt into a vlan packet.  This
>>makes things like (older?) dhcp work, for instance, so we have to
>>retain at least this feature.
>>
>>If we do not want to encapsulate q in q, that is fine...but it will
>>probably break some dhcp servers, at least.
> 
> 
> Hmm? If dhcpd is running on a VLAN interface tags should indeed be
> added to packets. (eth0.1 example above)

Perhaps I didn't understand what you were trying to say.

> Or do you mean that people run dhcpd on eth0 but expect it to still
> serve VLANs? I don't think that should work.

People run dhcp (and other programs I'm sure) on eth0.7 and send it
raw ethernet frames and expect that the vlan driver will do the work
of adding the vlan framing.

But, it would be equally valid to send a frame with the vlan-7 header
already in it to eth0.7, so that must continue to work (without
re-encapsulating it into eth0.7.7)


Ben

-- 
Ben Greear <[email protected]>
Candela Technologies Inc  http://www.candelatech.com