On Monday, April 4, 2011 07:55 AKDT, "Brandeburg, Jesse" 
<[email protected]> wrote: 
 
> 
> 
> On Fri, 1 Apr 2011, Jon wrote:
> 
> > Hello List,
> > 
> > I am trying to get a 82546G dual NIC Intel card to do bonding with vlans 
> > and a bridge for a xen server. I would like to be able to setup a bridge 
> > and then assign it to a VM(domU) so it is on a specific VLAN.
> > 
> > I have bonded  eth0 and eth1 to bond0 and have created a bridge and 
> 
> did you create the bridge in dom0 or ???

I created the bridge in dom0.

> 
> > assigned the vlan to the bridge. When I try to send data through the 
> > bridge and I am using tcpdump to sniff the wire I cannot see the VLAN 
> > tag in the packet.
> 
> using tcpdump in the virtual machine or the dom0 or domU?
>  


tcpdump in dom0 on the bridge(xenbr5) and the bonded interface(bond0)


> > I updated the driver to 8.0.30-NAPI because I had read that HW 
> > acceleration on the card with earlier drivers was stripping the VLAN tag 
> > off of the packet. But I am still not seeing the VLAN tag after updating 
> > the driver.
> 
> This is the kind of thing that usually has an issue (stacking of different 
> virtual interfaces) and does seem like it is just starting to work 
> correctly in the latest kernels.  That said I have no idea if it works in 
> el5 or not as I haven't directly tried it.
> 

Ok, thanks for that.

> > At this point I am lost and am not sure what to try next. Does this card 
> > support VLAN tagging? From everything I have read it does but can 
> 
> absolutely yes, it supports hardware vlan tag insertion and stripping.  
> One thing to note is that the hardware actually strips the vlan from the 
> packet data when hardware offload is enabled.  
> 

And thanks for that as well. :)

> > someone who knows for sure confirm that for me please? Is there 
> > something I am not understanding on why I am not seeing the tag? I have 
> > tried to ping, dhcp, ssh and nothing ever shows the VLAN in the packet.
> 
> but does the traffic over the vlan work?  without tcpdump enabled, 
> preferably.  The model we're trying to move to matches upstream's 
> declaration that when promisc mode is enabled (on the physical device) the 
> vlan tag is not stripped in hardware.  did you try tcpdump on eth0 or 
> eth1?
> 

The traffic does work but I am also seeing it on the eth2 interface and I 
didn't 
expect to see it there, that may just be my lack of understanding of vlans 
though.
I also did try tcpdump on eth0/1 and bond0 and xenbr5. I never saw the tag but 
I 
did see it on my dhcp server.

> Why are you using bonding to create a bridge?  a bridge connects two 
> networks through two devices, and a bond makes two devices connect to a 
> single network.  They seem opposed.
> 

Because I have 3 NICs and so I bonded two of them using mode 1 so in case I
lose a NIC I won't lose connectivity to all of the VM's.



I appreciate you taking the time to answer Jesse and I think the issue lies in 
what
you said above: 

"One thing to note is that the hardware actually strips the vlan from the 
packet data when hardware offload is enabled.".   

I had read this and tried to figure out what it would take to turn that 
"feature" off
but all I found was a patch to disable it. I also read that the later kernels 
would
not have this same behaviour.

So with that in mind I updated the box to a later kernel and a different OS and 
all
is working. I am now using Scientific Linux 6 with the 2.6.32 kernel. 

 modinfo e1000
filename:       /lib/modules/2.6.32.36/kernel/drivers/net/e1000/e1000.ko
version:        7.3.21-k5-NAPI
license:        GPL
description:    Intel(R) PRO/1000 Network Driver
author:         Intel Corporation, <[email protected]>
srcversion:     3895921F9A653A8C699A770


Thanks for the answer and sorry for wasting your time,

Jon

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