Subject: Re: Xen and VLANs
To: Manuel Bouyer <>
From: Johan Ihren <>
List: port-xen
Date: 01/07/2006 10:42:23
Hash: SHA1

Hi Manuel,

On 6 Jan 2006, at 17:43, Manuel Bouyer wrote:

>> Another alternative (vastly preferred from my POV) was if there was
>> any way to connect to the domUs from the dom0 without involving the
>> physical interface at all. I.e. if the dom0 also had one (or several)
>> "virtual" xennetN, then everything would work out just fine with a
>> cleaner design than both your workaround and my (non-functional)
>> attempt.
>> Would it be possible to add that?
> Yes, of course. When you have a xennetN in a virtual domain, there is
> a corresponding interface in dom0 named xvifX.N, where X is the  
> domain's
> number. You can then route or bridge these interfaces, leaving the  
> physical
> interface out of the setup

Umm, that's not what I wanted. I have a gazillion xvifN.M interfaces  
(well, at least more than 30) and I wasn't after micromanaging most  
of them from the dom0, especielly not for every state change among  
the domUs. I do, however, realize that it is probably possible to do  
that to achieve the behaviour I need that way.

What I wanted was a xennet0 in my dom0 that I can connect to the same  
bridge as my xennetN's in the domUs and then add all the VLANs on top  
of that. That way things will continue to work when I add or remove  
domUs. I.e. this should be a "local" xennet0 that the domU uses to  
talk to xennetN's in the domUs, not a reflection of the xennetN's in  
the domUs.

There is a commented out xennet device in the XEN0 config file:

#xennet*        at hypervisor?          # Xen virtual network interface

Is there any way of adding that back in a way that will give what I  
nned? It is not sufficient to just add it back, as the  
autoconfiguration won't detect any "xennet" hardware in the dom0.



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