[ovs-discuss] Vlan transparency in OVN

Ben Pfaff blp at ovn.org
Wed Jun 3 00:37:37 UTC 2020


On Tue, Jun 02, 2020 at 01:25:05PM +0200, Slawek Kaplonski wrote:
> Hi,
> 
> I work in OpenStack Neutron mostly. We have there extension called
> "vlan_transparent". See [1] for details.
> Basically it allows to send traffic with vlan tags directly to the VMs.
> 
> Recently I was testing if that extension will work with OVN backend used in
> Neutron. And it seems that we have work to do to make it working.
> From my test I found out that for each port I had rule like:
> 
>     cookie=0x0, duration=17.580s, table=8, n_packets=6, n_bytes=444, idle_age=2, priority=100,metadata=0x2,vlan_tci=0x1000/0x1000 actions=drop
> 
> which was dropping those tagged packets. After removal of this rule traffic was
> fine.
> So we need to have some way to tell northd that it shouldn't match on vlan_tci
> at all in case when neutron network has got vlan_transparency set to True.
> 
> From the discussion with Daniel Alvarez he told me that somehow we can try to
> leverage such columns to request transparency (for example: parent_name=none
> and tag_request=0). With this, northd can enforce transparency per port.
> 
> Another option could be to create an option in the “other_config” column in the
> logical switch to have the setting per Neutron network
> (other_config:vlan_transparent) While this seems more natural, it may break the
> trunk/subport current feature.
> 
> What do You, as ovn developers thinks about that?
> Is that maybe possible somehow to do currently in northd? Or is one of the
> options given above doable and acceptable for You?

This might be a place to consider using QinQ (at least, until Neutron
introduces QinQ transparency).


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