[ovs-discuss] Linux GRE ports don't show up in ovs-ofctl

Jesse Gross jesse at nicira.com
Thu May 14 05:24:09 UTC 2015

On Wed, May 13, 2015 at 10:14 PM, Manik Sidana <maniksidana019 at gmail.com> wrote:
> Thanks for your reply Jesse.
>>>You created an L3 tunnel but OVS is an Ethernet switch, so it doesn't
>>>know how to send traffic over it
> OVS can work on L2/L3/L4, then why it doesn't knows how to send
> traffic over it ?
> Do you mean that the tunnels created using OVS are L2 tunnels ? I
> understand that when we create tunnels using OVS, we specify remote
> and local IPs. Aren't these L3 tunnels.
>>>It is better to create tunnels
>>>directly through OVS than using the ip command as it is more scalable
>>>and less error prone. There are a number of tutorials on how to do
>>>this floating around.
> I'll have a look at it.
> I came across the below link while googling
> http://t32940.network-openvswitch-development.opennetworks.info/openswitch-and-gre-kernel-module-t32940.html
> The link says that OVS GRE tunnels support Ethernet encapsulation. But
> again, we give remote and local IP information in OVS GRE tunnels, so
> aren't these IP encapsulated tunnels.

The frames being encapsulated inside the tunnel are Ethernet (L2). The
outer headers that are used to transport the frame are IP (L3). OVS is
switching packets before they are encapsulated and so it needs to work
on the inner Ethernet frames.

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