[ovs-discuss] User space & kernel space actions.

[Justin Pettit]

> On Oct 20, 2015, at 9:10 PM, jimson jimson <jimsonchacko at gmail.com> wrote:
> 
> Hi
> 
> Are there any user space actions in ovs which can be done only at user space ? Any examples?

Yes, there are a few.  Setting an ARP field can only be done in userspace.

> Is 'normal' action a user space only action?

No, userspace figures out where the packet should go, but the pushes down kernel flows to do the forwarding.

> If we have a set of actions to be performed, say a user space action then a kernel space action , will they both be performed at the user space? Or is it like, the kernel throws exception -> ovs does user space action -> packet is given to kernel -> kernel does further processing ?

There's an explicit "userspace" action that acts like an output.  Actions will be executed in the order that they're listed, but sending to userspace doesn't pause the processing after it.

--Justin