[LiSA-Users] Regarding LiSA trunk mode

[Radu Rendec]

Hi,

Actually there are 2 distinct issues.

The first issue is related to distinct LiSA instances having the same
mac address on their virtual interfaces. But this should only affect
scenarios where "layer 3" functionality is involved: creating virtual
interfaces with "interface vlan NNN" and then assigning IP addresses.

The second issue is related to hardware acceleration of VLAN untagging.
When the NIC supports such acceleration, frames are already untagged at
the time when they come out of the NIC driver. Because right now there
is no support for this in LiSA, it can't properly handle these frames
and they get "lost". Since centos 6.3 has no support for "rxvlan" in
ethtool (actually there is no kernel support for this in 2.6.32), the
workaround for this is to use another type of NIC, which doesn't support
hardware acceleration of VLAN untagging.

I've managed to replicate Ammar's topology and reproduce the problem. I
can confirm that the problem is actually caused by hardware VLAN
untagging. But the problem is that I have no idea how to change the NIC
type for GNS3 VirtualBox guests. All NIC settings in VirtualBox are
overwritten by GNS3 at the time when it starts the virtual machines. I
couldn't find any NIC type setting in the GNS3 interface.

Cheers,

Radu

On Wed, 2013-05-29 at 23:52 -0400, chicany wrote:
> Hi,
> 
> 
> a few weeks ago I noticed a similar problem with non working trunk
> between two LiSA switches running on GNS3 with Qemu installed. The
> problem was that for each VLAN interface the same MAC address was
> generated on LiSA. The problem and workaround is described here (17
> c):
> 
> 
> http://brezular.wordpress.com/2010/09/25/lisa/
> http://forum.gns3.net/topic5647.html
> 
> 
> Cheers
> 
> 
> 
> 
> 2013/5/28 Radu Rendec <radu.rendec at mindbit.ro>
> 
>         Hi Ammar,
>         
>         The "show vlan" command only lists interfaces that are
>         configured in
>         access mode for each vlan. This is normal behaviour.
>         
>         Regarding your trunk problem, can you please send me a
>         screenshot of
>         your test topology and the output of "show runnning-config"
>         from the
>         lisa cli?
>         
>         One more thing: please post questions like this to the
>         lisa-users
>         mailing list. We don't have a (large) community, but we're
>         trying to
>         build one :)
>         
>         Thanks,
>         
>         Radu
>         
>         On Tue, 2013-05-28 at 09:35 +0800, ammar al-jubari wrote:
>         > Dear Mr. Radu
>         >
>         >
>         > First I would like to thank you for supporting Lisa. If you
>         allow me,
>         > I have a question regarding LiSA in GNS3.  I have built 2
>         LiSA
>         > switches and 4PCs topology in gns3 and virtual Box. It is
>         working well
>         > if all the ports are in access mode. I tried to make a trunk
>         link
>         > between 2 liSA, but it is not working. I used the following
>         commands
>         > to do that in the interface eth0 of both LiSA switches
>         > switchport trunk allowed vlan 5
>         > switchport mode trunk
>         >
>         >
>         > I noticed that when I show the VLAN table this port does not
>         appear in
>         > the list. When I changed it to access mode it appeared in
>         the list and
>         > it  is working well.
>         >
>         >
>         > Can you please help me with that or give me any suggestion
>         to solve
>         > this problem?
>         >
>         >
>         > I really appreciate your cooperation
>         >
>         >
>         >
>         >
>         > Regards
>         >
>         >
>         > Ammar
>         >
>         >
>         
>         
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> 
> 
> 
> 
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