[ovs-dev] [PATCH] netdev-vport: Fix support for "tap" devices.

Janis Hamme janis.hamme at student.kit.edu
Wed Nov 2 12:36:09 UTC 2011


On 10/31/2011 08:15 PM, Ben Pfaff wrote:
> On Mon, Oct 31, 2011 at 12:02:34PM -0700, Jesse Gross wrote:
>> On Mon, Oct 31, 2011 at 10:31 AM, Ben Pfaff <blp at nicira.com> wrote:
>>> Reported-by: Janis Hamme <janis.hamme at student.kit.edu>
>> This doesn't make a lot of sense to me: I think the only real use for
>> tap devices is for the userspace datapath where they resemble internal
>> ports.  Since the userspace datapath already does this conversion
>> automatically, I think the right thing to do is just remove tap
>> devices from the documentation.
> That's reasonable for "master" at least.  Janis (or anyone else), is
> there any particular reason you want to add a tap interface to your
> bridge?  In other words, is there any reason to continue supporting
> this feature?

I'am running two virtualbox vhosts that are connected to openvswitch.
The host running ovs should also be connected to the switch (br0
internal interface).
The vhosts are configured to use "briged adapter" so I can, in theory,
use either internal or tap interfaces to connect the vhosts.

If I create tap interfaces manually and use system interfaces in ovs to
add the tap interfaces
everything is working flawlessly.
Using internal interfaces results in communication problems between the
ovs host and the vhosts.

iperf between ovs host and vhosts (and vice versa) results in

iperf -s -i 1
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 10.0.0.1 port 5001 connected with 10.0.0.100 port 55410
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0- 1.0 sec  12.7 KBytes   104 Kbits/sec
[  4]  1.0- 2.0 sec  0.00 Bytes  0.00 bits/sec
[  4]  2.0- 3.0 sec  0.00 Bytes  0.00 bits/sec
[  4]  3.0- 4.0 sec  0.00 Bytes  0.00 bits/sec
[  4]  4.0- 5.0 sec  0.00 Bytes  0.00 bits/sec
[  4]  5.0- 6.0 sec  0.00 Bytes  0.00 bits/sec
[  4]  6.0- 7.0 sec  0.00 Bytes  0.00 bits/sec
[  4]  7.0- 8.0 sec  0.00 Bytes  0.00 bits/sec
[  4]  8.0- 9.0 sec  0.00 Bytes  0.00 bits/sec
[  4]  9.0-10.0 sec  0.00 Bytes  0.00 bits/sec
[  4] 10.0-11.0 sec  0.00 Bytes  0.00 bits/sec
[  4] 11.0-12.0 sec  0.00 Bytes  0.00 bits/sec
[  4] 12.0-13.0 sec  0.00 Bytes  0.00 bits/sec

Using manually created tap interfaces works so far, but as they are
destroyed on every reboot I have to reconfigure ovs, port numbers change
etc. ...
Is anyone else using virtualbox?

If ovs would create the tap interfaces automatically on startup that
whould be more comfortable. I'll try the patch and see if it is working now.

Janis




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